Article

Gradients of Abundance of Fish Across No-take Marine Reserve Boundaries: Evidence from Philippine Coral Reefs

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Abstract

1.An abundance gradient from high inside to low outside a no-take marine reserve may indicate net emigration of adult fish from the reserve (‘spillover’).2.We examined spatial patterns of abundance of fish across two ∼900 m long sections of coral reef slope at each of two small Philippine islands (Apo and Balicasag). One section sampled the entire length of a no-take reserve and extended 200–400 m outside the two lateral reserve boundaries. The other section, without a reserve, was a control. The reserves had had 20 (Apo) and 15 (Balicasag) years of protection when sampled in 2002.3.Significant spatial gradients of decreasing abundance of target fish occurred across only one (Apo Reserve northern boundary = ARNB) of four real reserve boundaries, and across none of the control ‘boundaries’. Abundance of non-target fish did not decline significantly across reserve boundaries.4.Abundance of target fish declined sharply 50 m outside the ARNB, but enhanced abundance extended 100–350 m beyond this boundary, depending on fish mobility.5.Density of sedentary target fish declined 2–6 times faster than density of highly vagile and vagile target fish across the ARNB.6.Habitat factors could not account for these ARNB results for target fish, but did influence abundance patterns of non-target fish.7.The lack of abundance gradients of target fish at Balicasag may reflect reduced fishing outside the reserve since it was established.8.Apo Reserve had a gradient of abundance of target fish across at least one boundary, a result consistent with spillover. Copyright © 2006 John Wiley & Sons, Ltd.

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... Moreover, some researchers report benefits of no-take protection for Philippine coral reefs (Piquero et al., 2015;Aaron-Amper & Gulayan, 2016), whereas others claim no effect (Abesamis, Russ & Alcala, 2006;Espectato, Napata & Baylon, 2017;Russ et al., 2021) and yet others suggest idiosyncrasy (Panga et al., 2021). Evidently, as with MPAs globally (Pendleton et al., 2017), continued research on the efficacy of Philippine MPAs is required to optimise coral conservation. ...
... Abesamis, Russ & Alcala, 2006;Espectato, Napata & Baylon, 2017;Panga et al., 2021;Russ et al., 2021). This discrepancy may arise for a variety of reasons. ...
... This discrepancy may arise for a variety of reasons. First,Abesamis, Russ & Alcala (2006) tested for linear changes in habitat complexity across zone boundaries, but did not attempt any nonlinear modelling or categorical reserve-control comparison, which could have detected differences overlooked by the chosen analysis. Second,Espectato, Napata & Baylon (2017) report no control values and studied MPAs that were over 93% smaller than the DIMRS SMAs. ...
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Situated in the coral triangle, the Philippines hosts some of the world's most diverse coral reefs. Yet there are few national marine protected areas (MPAs) in place that coincide with these reefs. Municipal MPAs partially alleviate this issue but a controlled comparison of the effects of different small‐scale management strategies on coral reefs is lacking. Danjugan Island Marine Reserve and Sanctuaries (DIMRS) is one of these community‐based MPAs that encompasses a collection of small (0.3–0.34 km2) marine reserves situated in a larger MPA where fishing is regulated through permits. The unique juxtaposition of different management strategies within DIMRS was used as a model system to test whether reserves are better for corals than limited fishing permits by comparing ecosystem indicators (coral cover, bleaching, disease, and morphological diversity). Total and live hard corals were 169% and 204% more abundant inside than outside no‐take zones in 2016. This distinction increased between 2002 and 2016 as a result of a more marked decrease in coral cover over time in the partially protected zones. A 70% higher coral community evenness outside the reserves further suggests that scleractinian coral communities on fished reefs are more disturbed. Live coral cover within the MPAs of DIMRS in 2016 (39 ± 4%) is above the current mean for Philippine reefs (23%) and is comparable with the long‐term average for reefs situated within Philippine MPAs (36%). This study suggests that exceptionally small reserves may benefit hard corals more than regulation via fishing permits.
... However, whether MPAs truly enhance fisheries remains controversial [8,18,19,20,21,22,23,24]. Fisheries can profit from two different processes after the initial recovery inside the MR: the export of propagules (recruitment effect), and the export of adults (spillover effect) outside of the MR [37,38,39,40]. Additionally, fish from MRs are relatively naïve to fishing and therefore more easily fished [41]. ...
... UVC is an indirect way of assessing spillover, as it does not involve tagging fish or tracking fish provenance. However, it is a reliable, non-destructive method with an established track record for detecting effects of MRs [38,39]. All of the 2012 surveys were conducted at 10m depth because surveys in 2003 and 2006 had shown no significant differences between two initial survey depths. ...
... Our study reports a larger area of spillover than most other studies. We found a spillover distance of more than 1km outside of the reserve, which contrasts with the distance values of 300-350m reported by some authors [38,49], or the 500m reported by others [80] [20,43]. One of the reasons for this larger spatial extent of spillover could be the homogeneity of the habitat around the border of the MR, a characteristic previously highlighted as a multiplier factor of the reserve's effects [81]. ...
Article
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The value of no-take marine reserves as fisheries-management tools is controversial, particularly in high-poverty areas where human populations depend heavily on fish as a source of protein. Spillover, the net export of adult fish, is one mechanism by which no-take marine reserves may have a positive influence on adjacent fisheries. Spillover can contribute to poverty alleviation, although its effect is modulated by the number of fishermen and fishing intensity. In this study, we quantify the effects of a community-managed marine reserve in a high poverty area of Northern Mozambique. For this purpose, underwater visual censuses of reef fish were undertaken at three different times: 3 years before (2003), at the time of establishment (2006) and 6 years after the marine reserve establishment (2012). The survey locations were chosen inside, outside and on the border of the marine reserve. Benthic cover composition was quantified at the same sites in 2006 and 2012. After the reserve establishment , fish sizes were also estimated. Regression tree models show that the distance from the border and the time after reserve establishment were the variables with the strongest effect on fish abundance. The extent and direction of the spillover depends on trophic group and fish size. Poisson Generalized Linear Models show that, prior to the reserve establishment , the survey sites did not differ but, after 6 years, the abundance of all fish inside the reserve has increased and caused spillover of herbivorous fish. Spillover was detected 1km beyond the limit of the reserve for small herbivorous fishes. Six years after the establishment of a community-managed reserve, the fish assemblages have changed dramatically inside the reserve, and spillover is benefitting fish assemblages outside the reserve.
... Although marine protected areas (MPAs) are widely recognized as an important tool for biodiversity conservation (Claudet et al., 2008;Giakoumi et al., 2017) and fisheries management (Abesamis, Russ, & Alcala, 2006;Goñi et al., 2008;, the prevalence of fisheries benefits delivered by MPAs is still largely debated (Hilborn, 2016;Kerwath, Winker, Götz, & Attwood, 2013; . While both processes require populations to firstly recover within the boundaries of the FPAs, generally the former is key to the long-term persistence of exploited populations also at relatively large distances from the MPA (i.e. ...
... The maximum distance from FPA borders at which spillover effects are still detectable is a crucial issue to better understand the spatial extent of FPA benefits to local fisheries. Most studies found that spillover occurs at distances of about 200 m from FPAs' borders, and all agree that it does not exceed 1 km (Abesamis et al., 2006;Guidetti, 2007;Marques, Hill, Shimadzu, Soares & Dornelas, 2015;. According to Di Lorenzo et al. (2016), two types of spillover should be considered based on the measurable benefits generated: "ecological spillover" encompassing all forms of net emigration of juveniles, subadults and/or adults from the MPA outwards; and "fishery spillover", that is the fraction of ecological spillover that can directly benefit fishery yields and revenues through the marine species biomass that can be fished (Di Lorenzo et al., 2016). ...
... size, shape, location), presence of PPAs, the level of enforcement and habitat continuity/discontinuity across FPA borders (Goñi et al., 2008;Kaunda-Arara & Rose, 2004;Kay, Lenihan, Kotchen, & Miller, 2012); and (b) species characteristics-the species-specific ability to move across the FPA borders related, for example, to the intraspecific behaviour of individuals, habitat preferences, species mobility, commercial value and fishing pressure (Kaunda-Arara & Rose, 2004). Some studies reported that spillover may require many years (>10 years) to take place after a FPA is established (Abesamis et al., 2006;, while others detected spillover after only a few years from FPA establishment (<5 years) Guidetti, 2007). Spillover has been observed from FPAs surrounded or not by a PPA (Abesamis et al., 2006;Zeller, Stoute, & Russ, 2003) and detected from both small (< 1km 2 ) (Abesamis et al., 2006; and large FPAs (Ashworth & Ormond, 2005;Fisher & Frank, 2002; Spillover is expected to mostly occur for relatively mobile species (Buxton, Hartmann, Kearney, & Gardner, 2014;, but some studies showed that also sedentary species Eggleston & Parsons, 2008;Forcada et al., 2009;Goñi et al., 2006Goñi et al., , 2008Zeller et al., 2003), as well as vagile (Abesamis et al., 2006;Forcada, Bayle-Sempere, Valle, & Sánchez-Jerez, 2008;Guidetti, 2007) and highly vagile species Kaunda-Arara & Rose, 2004;, may spillover beyond FPA borders. ...
Article
Marine Protected Areas (MPAs), if well designed and managed, can produce conservation benefits to fish assemblages within no-take zones and fishery benefits in neighboring areas through 'spillover'. However, although plenty of studies have provided evidence of the benefits produced within MPA boundaries, overall benefits to local fisheries, especially via spillover, seem to be still unclear. Because of the lost fishing grounds following an MPA establishment, local fishermen usually oppose MPAs. There is, therefore, the urgent need for a better understanding of the mechanism(s) through which MPAs can export fishable fish biomass towards adjacent fished areas, a process that could counterbalance the loss of fishing grounds. Here we review the literature on spillover for refining the terminology, detailing the underlying mechanisms and identifying both the existing and needed methodological approaches to measure spillover. Operationally, two types of spillover should be considered: ecological spillover (i.e. the net export of juvenile, subadult and adult biomass from MPAs outwards driven by density-dependent processes) and the fishery spillover (i.e. the proportion of this biomass that can be fished, taking into account regulations and accessibility). Underwater visual census and tagging/tracking may allow getting evidence of ecological spillover, while experimental catch data are essential to assess and monitor fishery spillover, which is the main component of MPAs that can provide direct benefit to local fisheries.
... Thirdly, catch rates of some species (Acanthuridae) were found to be higher near the reserve than elsewhere around Apo Island after two decades of reserve protection (Russ et al., 2003Russ et al., , 2004). Fourthly, recent studies indicate that patterns of decreasing abundance of some targeted species are present across the northern boundary of the reserve (Abesamis et al., 2005). Lastly, a recent study indicates that density-dependence may be driving net emigration of adult fish (Naso vlamingii (Valenciennes)) from the reserve (Abesamis and Russ, 2005). ...
... Fourthly, recent studies indicate that patterns of decreasing abundance of some targeted species are present across the northern boundary of the reserve (Abesamis et al., 2005). Lastly, a recent study indicates that density-dependence may be driving net emigration of adult fish (Naso vlamingii (Valenciennes)) from the reserve (Abesamis and Russ, 2005). On the other hand, no direct evidence is available to show that fishing effort near Apo Reserve has remained low over the last two decades. ...
... Fishermen may know from experience that hook-and-line and spear gun catch rates are low nearest the reserve (0−100 m), hence they tend to avoid fishing in this area. Experimental fishing with hooks and line, but specifically targeting N. vlamingii, supports the contention that hook-and-line CPUE is low very close to the boundary of Apo Reserve (Abesamis and Russ, 2005). Hook-and-line CPUE for N. vlamingii was higher at intermediate distances (150−200 m) than at the closest (50−100 m) and farthest (250−300 m) distances from the reserve (Abesamis and Russ, 2005). ...
Article
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The contribution of the no-take marine reserve at Apo Island, Philippines, to local fishery yield through "spillover" (net export of adult fish) was estimated. Spatial patterns of fishing effort, yield, and catch rates around Apo Island were documented daily in 2003-2004. Catch rates were higher near the reserve (by a factor of 1.1 to 2.0), but fishing effort was often lowest there. Higher catch rates near the reserve were more likely due to spillover than to low fishing intensity. Lower fishing effort near the reserve may have been due to 1) weather patterns, 2) traditional importance of other fishing grounds, 3) high variability in catch rates, 4) lower market value of target species, and 5) social pressures. The yield taken near the reserve was only 10% of the total yield, but the actual spillover contribution was probably much less than this. This study is one of the few to estimate the spillover contribution to overall yield and to document the responses of fishermen to spillover.
... (e.g. [30,31]). Related results were given in our previous paper [2] for efflux from a circular NTA. ...
... Since |∇θ| = F/D, in some circumstances the magnitude of the gradient outwards from an NTA may decrease as D −1/2 even though the spillover flux increases as D +1/2 . This is consistent with the finding in [30] that the population density gradient of a highly motile species may be 2-6 times lower than for a sessile species outside of a boundary of a small NTA that is not heavily fished. This is readily explained by a diffusion coefficient that is 4-36 times higher for the more motile species. ...
... There is a density gradient for the stationkeepers that is discernible out to x = 1.5 km in Figure 3, which is around 300 m out from the NTA boundary. This is in agreement with measurements taken in the Philippines [30] and in the Mediterranean [31]. Figure 3 also indicates that the lower-mobility station-keepers are relatively better off in the NTA and relatively worse off outside of it. ...
Article
Mobility stratification, identifiable from k-means clustering on an appropriate displacement data set, is a common feature of many fish species wherein distinct low-mobility ‘station-keeper’ and high-mobility ‘ranger’ types are recognized. From recapture records of speckled snapper Lutjanus rivulatus, we develop a Gaussian mixture model of the probability density function for random displacements by the two types. This leads to a system of two coupled reaction-diffusion equations. We consider a single no-take area (NTA) in one and two dimensions containing a mobility-structured species. The minimum size of this NTA that leads to species survival is derived and then generalised to a population with n mobility types. Exact non-uniform 1-D steady states are constructed for the full nonlinear mobility-structured model with lethal (zero density boundary condition) harvesting outside of the NTA. This model is then extended to include an array of evenly spaced NTAs with a bounded harvesting rate allowed between them. The minimum size of linear, circular and annular NTAs and the maximum sizes of the surrounding fractionally harvested zones that ensure species survival and connectivity are calculated.
... The different conclusion reached in this study may reflect regional disparities in the primary reef fish species targeted by fishers and their role in ecosystem functioning. For example, the removal of major groups of herbivores, such as those targeted in the Philippines (Abesamis et al. 2006), increases the vulnerability of coral communities to phase shifts towards reefs dominated by algae (Bellwood et al. 2006), which are known to enhance dissolved organic carbon, thereby stimulating microbial growth (Haas et al. 2011). However herbivorous fishes face insignificant fishing pressure on the GBR (Bruno et al. 2009). ...
... As a result, the effectiveness of spatial closures in sustaining coral health will be largely dependent on the level of user compliance, community awareness and support that exists for their use (e.g. Alcala & Russ 2006). It is essential that users be made aware of the potential long-term benefits of sustained marine reserve protection (see Selig & Bruno 2010). ...
Thesis
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The recent global emergence of coral disease outbreaks and subsequent coral mortality is commonly linked with human activities, however almost nothing is known about the influence of marine-based industries on coral disease. Given the growing demand for coastal development and natural resource extraction in locations that overlap with coral reefs, and growth of industries that rely on coral reefs, particularly tourism and fishing, resource managers need tools to combat coral disease epizootics and prevent future outbreaks. Research presented in this thesis identifies factors associated with industries that influence coral disease and evaluates existing and potential management tools for mitigating their impacts. Concentrating tourism activities can be an effective way to closely manage high-use parks and minimise the effects of visitors on plants and animals, however, the effects of reef-based tourist facilities on coral health have not been assessed. In partnership with reef managers and the tourism industry, in Chapter 2, I test the effectiveness of concentrating tourism activities on reefs with and without permanent tourist platforms as a strategy for managing tourism on coral reefs in the Great Barrier Reef Marine Park. Coral diseases were 15 times more prevalent at reefs with offshore tourism platforms than at nearby reefs without platforms. The maximum prevalence and maximum number of cases of each disease type occurred at reefs with permanently moored tourism platforms. Diseases affected 10 coral genera from 7 families at reefs with platforms, but only 4 coral genera from 3 families at reefs without platforms. The greatest number of disease cases occurred within the spatially dominant acroporid corals, which exhibited 18-fold greater disease prevalence at reefs with versus without platforms. Neither the percent cover of acroporids nor overall coral cover differed significantly between reefs with and without platforms, which suggests that neither factor was responsible for the elevated levels of disease. Identifying how tourism activities facilitate coral disease will help ensure ongoing conservation of coral assemblages and tourism. Recreational scuba diving on coral reefs is one of the fastest growing tourism sectors globally. Although physical injury and sedimentation associated with intensive dive tourism has been documented extensively, other impacts on coral health are unknown. In Chapter 3, I compare the prevalence of 4 coral diseases and 8 other indicators of compromised health at five of the highest and lowest used dive sites around the small community-managed island of Koh Tao, Thailand. The mean prevalence of healthy corals at low-use sites (79%) was twice that at high-use sites (45%). I found a 3-fold increase in coral disease prevalence at high-use sites, and significant increases in sponge overgrowth, physical injury, tissue necrosis from sediment, and non-normally pigmented coral tissues. Sediment necrosis was strongly associated with white syndrome prevalence across all sites. Injured corals were more susceptible to skeletal eroding band disease only at high-use sites, suggesting that additional stressors associated with use intensity facilitate disease development. Unexpectedly, I observed 113 corals entangled in derelict fishing line, of which 87% had ciliates associated with skeletal eroding band disease initiating from lesion boundaries, increasing disease susceptibility 5-fold compared to non-entangled corals, an unreported mechanism of coral mortality associated with fishing gear. Use of numerous indicators of coral health increases understanding of impacts associated with rapid tourism growth. Identifying practical management strategies, such as spatially separating multiple reef-based activities, is necessary to balance the expansion of tourism and maintenance of coral health. The rapid pace of coastal development near sensitive coral reef ecosystems necessitates a comprehensive understanding of the impacts that development activities have on all aspects of coral health. While elevated sedimentation and turbidity are often cited as drivers of reef decline, their influence on coral disease prevalence has never been investigated in situ. In Chapter 4, coral health surveys were conducted along a dredging-associated sediment plume gradient to assess the relationship between sedimentation, turbidity and coral health near Montebello and Barrow Islands, Western Australia. Reefs exposed to the highest number of days under the sediment plume (296 to 347 days) had 2-fold higher levels of disease, largely driven by increases in white syndromes, and a 6-fold increase in other signs of compromised coral health, relative to reefs with little or no plume exposure (0 to 9 days). Multivariate modeling and ordination incorporating sediment exposure level, coral community composition and cover, predation and multiple thermal stress indices provided further confirmation that the level of sediment plume exposure was the main driver of elevated disease and other indicators of compromised coral health. This study provides the first empirical evidence linking sedimentation and turbidity with elevated coral disease prevalence in situ. Minimising sedimentation and turbidity associated with coastal development will provide an important management tool for controlling coral disease epizootics. A limited number of options are available for directly managing diseases in marine environments. In Chapter 5, the utility of marine reserves for mitigating coral disease was assessed for the first time in the Great Barrier Reef Marine Park. Comparisons of coral disease assemblages and the prevalence of six individual diseases among sites with protection versus sites with fishing revealed that no-take reserves resulted in a 3-fold reduction in pooled coral disease prevalence. Of the 31 explanatory factors tested, including habitat and environmental characteristics, fish assemblages, and differences in fishing gear restrictions, a multivariate regression demonstrated that protection from fishing was the primary factor explaining variability in coral disease assemblages. Further, significant partial correlations with coral damage and the abundance of derelict fishing line indicate that direct damage associated with line fishing is the primary driver of differences between protection levels. Gear restrictions within fished zones did not improve coral health, instead I found significantly greater levels of skeletal eroding band disease, white syndromes, coral damage, and derelict fishing line when gear was restricted, compared to unrestricted. Moreover, within fished zones, the prevalence of skeletal eroding band disease, coral damage, and fishing line increased with increasing proximity to the nearest reserve boundary, signifying that fishers target areas just outside of reserve boundaries due to ease of accessibility from boat moorings located within reserves or perceptions that fish stocks are less depleted near reserve boundaries. This study concludes that both protection from fishing and spatially managing use-intensity within fished areas are important strategies to improve coral health. This thesis consistently demonstrates that reducing stressors associated with marine-based industries can ameliorate coral health and alleviate the impacts of disease. Identifying and implementing effective management strategies to improve coral health represent practical tools for increasing the resilience of vulnerable reef ecosystems in a changing climate and developing world.
... It is therefore necessary to know where and in what quantity are to be found the habitats already known to play a nursery role , and furthermore which are the other habitats of the seascape mosaic of the rocky infralittoral that play a nursery role. In addition, it will be necessary to protect parts of the adult habitats, from which the fishing grounds may be resupplied with adults by spill-over effect (Abesamis et al. 2006;Grüss et al. 2011;Goni et al. 2008). Finally, it is also necessary to ensure that the nurseries are present in sufficient number and at the right distance from the adult habitats, in order to guarantee satisfactory connectivity between these habitats and enable ontogenic migration Di Franco et al. 2012;Gillanders et al. 2003). ...
... Il faut donc savoir où et en quelle quantité se trouvent les habitats dont le rôle de nourricerie est déjà connue (Chapitre II), et de plus quelles sont les autres habitats de la mosaïque paysagère de l'Infralittoral rocheux qui jouent un rôle de nourricerie (Chapitre III) ? De plus on cherchera à protéger des portions d'habitats des adultes, à partir desquels les zones exploitées pourront être réapprovisionnées en adultes par effet spill-over (Abesamis et al., 2006;Goni et al., 2008;Grüss et al., 2011). Enfin il faut également s'assurer que les nourriceries sont présentes en nombre suffisant et à distance adéquate des habitats adultes, pour garantir une bonne connectivité entre ces habitats et permettre les migrations ontogéniques Di Franco et al., 2012;Gillanders et al., 2003). ...
... The four species that are included in the IUCN red list were also mostly found inside MPAs. Our study is consistent with the findings of previous studies, which also reported overall higher density of commercially important fishes inside MPAs in the Philippines (Russ and Alcala, 2003; Abesamis et al., 2006; Maliao et al., 2009). The overall better condition of commercially important coral reef fishes inside MPAs, despite being small (i.e. ...
... Considerable anecdotal accounts have been reported during various FGDs with fishers that MPAs have resulted in higher catches (Muallil et al., 2014aMuallil et al., , 2014b). However, except for the works of Russ and Alcala (2003) in the well enforced Apo reef MPAs (see also Abesamis et al., 2006; Alcala and Russ, 2006), there is a lack of empirical evidence that MPAs in the Philippines can benefit the local fisheries. Maliao et al. (2009) showed an overall higher biomass and density of commercially important coral reef fishes inside MPAs but neither fish biomass nor density increased with increasing years of protection for a given MPA. ...
Article
Establishment of marine protected areas (MPA) is among the most commonly implemented initiatives for coral reef conservation and fisheries management in the Philippines. However, there are concerns that the MPAs in the country may not work because of their generally small sizes and high fishing pressures from the burgeoning highly resource-dependent population. In this study, we assessed the assemblages of seven commercially important coral reef fish families (Acanthuridae (excluding genus Zebrasoma), Labridae (subfamily Scarinae only), Lutjanidae, Serranidae (subfamily Epinephelinae only), Mullidae, Haemulidae and Lethrinidae) inside and outside MPAs in 37 coastal municipalities in the Philippines. A total of 12,354 individuals belonging to 114 species (33 species of Acanthuridae, 27 species of Scarinae, 17 species of Lutjanidae, 16 species of Epinephelinae, 9 species of Mullidae, 6 species of Haemulidae, and 6 species of Lethrinidae) were recorded. Overall, reef fishes inside MPAs were more diverse than outside MPAs based on Shannon-Wiener index of diversity. Reefs inside MPAs had an average of four more fish species than outside MPAs. Both inside and outside MPAs had comparable equitability values which are characterized by fish communities that are largely dominated by few species only. Higher fish densities, especially fishes with (total length), were also recorded inside MPAs. However, we also found some patterns suggesting that more efforts must be made inorder to effectively protect many of the commercially important coral reef fishes from the impacts of fishing. Our study provides valuable science-based insights that can be used to improve coral reef conservation and fisheries management initiatives in the country. Moreover, it can also serve as crucial information that can be used for monitoring and evaluation of MPA effectiveness, particularly on commercially important coral reef fishes in the country.
... underwater visual censuses have determined that patterns of biomass across NTA boundaries are consistent with spillover of fish biomass , Ashworth & ormond 2005. For example, gradients of target reef fish abundance spanned the boundary of Apo Island NTA in the Philippines, with greatest abundances inside, intermediate abundance generally within 50 m of the NTA boundary and abundances consistent with fished areas within 100 m of the NTA boundary (Abesamis et al. 2006). Tagging studies have shown fish moving across NTA boundaries into fished areas, with either one-way movements (kaunda-Arara & Rose 2004a) or repeated, often seasonal, crossings associated with movement among feeding and spawning grounds (Meyer & Holland 2005). ...
... cPuE for the acanthurid Naso vlamingii in the NTA boundary area was similar to that in an adjacent fishing ground (katipanan) but 45 times higher in the boundary area than in the wider Apo Island fishing grounds . Another study of the same NTA found that catch was higher near the reserve, but fishing effort adjacent to the reserve was lower (Abesamis et al. 2006). ...
... Depending on their objectives, MPAs are classified according to their conservation status, which vary from no-take zones (small or large areas where all extraction activities are strictly prohibited) to multipurpose MPAs, in which human activities are authorized and regulated (Kelleher, 1999;Hilborn et al., 2004;Claudet, 2006;Di Franco et al., 2009;Lester et al., 2009;Gascuel and Henichart, 2011;Al-Abdulrazzak and Trombulak, 2012;Sciberras et al., 2013). Several approaches exist to assess the effects of MPAs on fish assemblages: studies of their evolution within the MPA (McClanahan et al., 1999;Mosquera et al., 2000;Gell and Roberts, 2003;Evans and Russ, 2004;Stobart et al., 2009;Molloy et al., 2009;Babcock et al., 2010;Hoskin et al., 2011), comparison before and after closure to fishing (Halpern and Warner, 2002;Albaret et al., 2005;Claudet et al., 2010;Moland et al., 2013;Ecoutin et al., 2014), and comparative studies between areas inside and outside the MPA (Westera et al., 2003;Kamukuru et al., 2004;Denny and Babcock, 2004;Abesamis et al., 2006;Watson et al., 2009;Sciberras et al., 2013;Ecoutin et al., 2013). ...
... All the species present in the MPA but not found in the exploited site were high trophic level predators. The average abundance observed in the MPA was higher than that observed in the exploited site (Johnson, 1999;Williamson et al., 2004;Kamukuru et al., 2004;Micheli and Halpern, 2005;Abesamis et al., 2006;Watson et al., 2009;Harmelin-Vivien et al., 2008;Watson et al., 2009). This difference is related the increase in the abundance of E. fimbriata in the MPA and its decrease in the exploited site (Ecoutin et al., 2013). ...
... Baseline information on the species diversity, distribution, and status of sea cucumber stocks in many geographical areas is inadequate for developing an appropriate and science-based management strategy. Although marine protected areas (MPAs) are known to be an effective fisheries management tool (Alcala, 1999;Abesamis et al., 2006;De Guzman, 2016), few studies have evaluated their role in maintaining diversity and populations of sea cucumbers (Cariglia et al., 2013;De la Cruz et al., 2015). This paper is an output of a nationwide program funded by the Commission on Higher Education (CHED) on the Species Inventory and Fisheries Assessment of Sea Cucumbers in Key Biogeographical Regions in the Philippines. ...
... No-take MPAs had been proven to build up populations and biomass of target food fish (Abesamis et al., 2006;De Guzman, 2016;Muallil et al., 2019) and valuable invertebrates such as sea cucumbers (DNSC, 2013;De Guzman and Quiñones, 2013;Calagui et al., 2015;De la Cruz et al., 2015). Tests comparing mean densities and variances of seven high-value species found across five survey sites (Fig. 8) show significant differences between MPA and non-MPA sites (t-test, p <0.05; F-test, p<0.005). ...
Article
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Marine protected areas (MPAs) are considered strategic tools in conserving biodiversity and maintaining stocks of valuable resources. We assessed sea cucumbers in five provinces in northeastern and western Mindanao to describe the state of diversity and abundance and evaluate the role of MPAs in sustaining stocks of exploited species. We identified 36 species of sea cucumbers from fishery-independent surveys on shallow reef flats and deeper reef slopes, of which 33 species (92%) belong to order Aspidochirotida and three species belong to Order Apodida. The majority are shallow-water holothurians occurring on reef flats and seagrass beds, while a few species are found along reef slopes or in fresh catches by fishers sold to local traders or processors in some sites. Nine species are considered high-value to the global trepang trade but occur at low densities, while the rest are abundant or common species with low commercial value. Species richness (S=17-30 spp.) varies across sites, but species composition similarity is relatively high (Sørensen’s SQ = 0.62-0.78). Mean population densities and variances of high-value species are significantly higher inside enforced MPAs than in non-MPA sites(t-test, p <0.05; F-test, p<0.005) across five survey sites. The abundance of high-value H. scabra in Tubajon and H. fuscogilva in Capayas Island demonstrates the critical role of MPAs in conserving biodiversity, maintaining population levels, and ensuring natural recruitment of sea cucumber resources. Urgent management measures such as formulating a national management plan, regulating harvests, and establishing no-take MPAs are recommended.
... Benthic habitat for each site was described as percent cover of each substrate type, which was equivalent to the number of points recorded per substrate type along each transect (since there were 100 points per transect). In addition, benthic habitat for each site was described as a single habitat complexity index (HCI) modified from a study done in the same region (Abesamis et al. 2006): HCI = (mean rugosity + 1) × (hard coral cover + 1). For this index, coral cover was expressed as a proportion (0 to 1), with 100% cover = 1. ...
... Lower values indicated relatively flat expanses of sand, rubble, or rock with low hard coral cover. The original HCI proposed by Abesamis et al. (2006) included values for mean reef steepness and ranged from 1 to 50. In the present study, mean reef steepness was excluded in the computation of HCI, since all sites were inshore reefs with very gradual reef slopes. ...
Article
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No-take marine reserves are expected to enhance coral reef resilience indirectly through suppression of algal growth and thus maintenance of coral dominance. The mechanism of such enhancement is protection of functionally important herbivorous fishes from harvest. We provide indirect (inferred) evidence of reserves performing this role. We used data on herbi-vorous fishes, macroalgae and corals collected at one point in time in 15 reserves (range of duration of protection: 0.5 to 11 yr) and at 15 fished sites in the Philippines. Results inferred a 9-and 15-fold increase in density and biomass, respectively, of herbivorous fishes, which coincided with a 13-fold decrease in macroalgal cover inside reserves after 11 yr of protection. The inferred decline in macroalgal cover was more rapid during the first 5 yr of protection. No significant trends in fish abundance or macroalgal cover were detected among fished sites. Bio-mass of herbivorous fishes was 8 times higher, and cover of macroalgae 25 times lower, on average, inside older (8 to 11 yr) reserves than at fished sites. Parrotfishes (Scaridae) and surgeonfishes (Acanthuridae) had markedly different inferred trajectories of population recovery. Recovery of parrotfish was more rapid than that of surgeonfish in the first 5 yr of protection, suggesting that the functional role of parrotfish was important in reducing macroalgal cover. The inferred relationships of hard coral cover with duration of reserve protection and with herbivore biomass were non-significant. Even at fished sites, coral cover (mostly > 25%) was much higher than macrolgal cover (mostly <15%). Thus, there was no evidence that the current levels of fishing of herbi-vores on these reefs have led to 'benthic phase shifts'.
... In this dynamic, the use of marine protected areas (MPA), or marine reserves as a tool of fishery management and recovery of degraded ecosystems is recommended (Mangel, 2000;Pikitch et al., 2003;Cury et al., 2005Cury et al., , 2008. Several studies have demonstrated their positive impacts in regenerating the taxonomic diversity (Gell & Roberts, 2003;Abesamis, Russ, & Alcala, 2006). In response to the new approach, a network of protected areas covering the major West African coastal watersheds has been created. ...
Article
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The Bamboung protected area (Senegal, West Africa) has been implemented in 2003. However, little is known about its recovering effects on fish assemblage functional diversity. To address this issue, a morphology-based functional grouping was adopted, and results were compared to prior classifications. Functional richness relative to each guild and species abundance was used to define a functional redundancy index. Morphometric measurements were done in the field on freshly killed specimens and completed by digital image processing using the Image-J software in laboratory. Data relative to biomass and abundance were obtained from the IRD (Research Institute for Development) / Adaptive Response of Fish Assemblages to the Environmental Pressure (RAP) Unit-Research database. Hierarchical clustering, analysis using the ward method, was applied to the matrix of morphological traits to discriminate fish assemblages into four functional guilds: zoobenthos feeders, algivorous / detritivorous fish, benthopelagic fish, and demersal and ichthyophagous fish. The new functional grouping reduced fish assemblage complexity to smaller and more significant units than those obtained from previous gut-content based-classification, and the modifications affecting fish biomass distribution after fishing ban, marked by large predatory fishes domination appeared more perceptible. Classification based on fish life-history traits showed similar results with a domination of fish assemblages by marine species of larger size and upper trophic level. However, this latter approach is still relevant as it provides significant information on fish species mobility and community dynamics. Major observed changes occurred after one to three years of protection. The total fish biomass varied from 6458 kg.km-2 in 2003 to 3114 kg.km-2 in 2007. We hypothesized that collapse in total fish biomass may be explained by predation pressure in the system. Species richness varied from 51 in 2003 to 72 in 2007, while the functional redundancy index showed a decreasing trend indicating a functional diversification in the system subsequent to the reserve establishment. The present study highlights the relevance of multiple approaches model in addressing dynamics of complex systems. However, the present trend does not presage the future evolution in the system, many reserves take over a decade to get a stable state.
... This proximal increase may occur through movement of fish with a home range greater than a marine sanctuary or through density dependent interactions [19][20][21]. However, this movement can be spatially constrained with distance from a sanctuary boundary [22,23], and will depend strongly on the taxa [24] and habitat continuity across zone boundaries [25]. ...
Article
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Abundance and length of the highly-targeted snapper Chysophrys auratus were compared between sites in 'no take' areas (Sanctuary Zones: SZ), partial protected areas which are fished (Habitat Protection Zones: HPZ), and areas outside (Outside) the Solitary Islands Marine Park (SIMP), Australia. Baited Remote Underwater Video (BRUV) sampling on shallow rocky reef (15 - 25 m) was conducted annually from 2002 until 2014 in the Austral-winter, covering the decade after these marine park zones were established (2002). Additional deeper sites (25 - 40 m) were sampled in 2010-2011 to assess if findings were more-broadly applicable. Lengths were measured using stereo-BRUVs from 2011-2014. Snapper were significantly more abundant in SZ overall and in most years compared with the other two management types, which did not significantly differ. Snapper rapidly increased after 2 - 3 years protection in all management types, especially SZ. Snapper were present on more SZ deployments than HPZ and Outside after the same period. The positive SZ response in snapper abundance on shallower reef was also found at a broader spatial scale on deeper sites. Again the two fished management types did not show significant differences among each other. There was considerable variation in snapper abundance between years, with strong peaks in 2005, 2009 and 2014 especially in SZ. Abundances remained higher in SZ in the year or two following a strong peak, but decreased to similar abundances to fished areas before the next peak. Snapper length frequency distribution significantly differed between SZ and both fished management types, with more larger snapper within SZ including a higher proportion (58%) that were legal-sized (>25.7 cm FL). HPZ and Outside did not significantly differ from each other, and were dominated by individuals below legal size. Overall, SZ's have positively influenced abundance and length of snapper on these subtropical rocky reefs.
... Indeed, reserve effect has been found to be principally obvious closed to MPA borders (Abesamis et al., 2006b;Goñi et al., 2008;) with a decreasing gradient of resource biomass from inside the MPA to exploited areas Harmelin-Vivien et al., 2008). This generally leads to a strong fishing effort close to MPA boundaries Stelzenmuller et al., 2008). ...
Thesis
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These last decades have been characterized by a great development of fishing techniques, contributing to the overexploitation of numerous marine fish stocks. In order to limit this collapse and to restore impacted communities, the implementation of management measures was necessary. Marine Protected Areas (MPAs), initially developed to protect remarkable habitats and associated biodiversity, are more and more used as a tool for spatial management of fishing activities, by adult export and/or larvae migrations from protected zones to surrounding fisheries. The aim of this PhD was to use indicators and predictive models for evaluating the impact of the Bonifacio Strait Natural Reserve (Corsica) implementation on fish communities and the benefits of such management measures for the local artisanal fishery. Artisanal fishery catch data from south Corsica has permitted to highlight the indirect impact of recreational fishing on exploited fish communities structure and biomass. Although a decrease in fishing effort may contribute to increasing catches per unit effort (CPUE), the analysis using response groups helped us to reveal a distinct increase in the artisanal fishery catches for target species of spearfishing. We then developed a model and tested management scenarios for maintaining the spiny lobster resource, in decline in the reserve, into a sustainable exploitation way. Our results show that even if the BSNR legislation represents a benefit for many species, it is not sufficient to allow for the recovery of the red spiny lobster. Indicators issued from the ISIS-Fish model showed that higher restrictions on this resource access are necessary. After comparing various management measures, it appeared that the best compromise should be to authorize lobster nets use only during the summer season (July and August), for limiting the collapse of the population while offering a long term benefit for fishers, in the objective of sustainable fisheries.
... It is therefore necessary to know where and in what quantity are to be found the habitats already known to play a nursery role (Cheminée et al. 2011), and furthermore which are the other habitats of the seascape mosaic of the rocky infralittoral that play a nursery role. In addition, it will be necessary to protect parts of the adult habitats, from which the fishing grounds may be resupplied with adults by spill-over effect (Abesamis et al. 2006;Grüss et al. 2011;Goni et al. 2008). Finally, it is also necessary to ensure that the nurseries are present in sufficient number and at the right distance from the adult habitats, in order to guarantee satisfactory connectivity between these habitats and enable ontogenic migration (Cheminée et al. 2011;Di Franco et al. 2012;Gillanders et al. 2003). ...
Chapter
Several concepts revolve around the term "marine landscapes": All of them are nourished by aggregating data from multiple sources and disciplines. The SINP (Système d'Information sur la Nature et les Paysages) is the French marine biodiversity and landscape building block in the global marine data infrastructure pyramid. Within this information system marine landscapes have been apprehended in both a pictorial and an ecological manner, therefore the usages of the SINP depend on the adopted definition. Through examples we argue that by increasing the availability of the massive volumes of cross-domain data necessary for apprehending landscapes, regardless of the chosen definition, the SINP can play a role in defining and refining our understanding of marine landscapes. © Springer International Publishing Switzerland 2014. All rights are reserved.
... L"utilisation de la senne tournante dans le cadre des campagnes de biocontrôle semble peu adéquate dans le contexte de protection, vu que l"habitat subit momentanément une perturbation et la biomasse retirée n"est pas réintroduite dans le système. En ce sens, nous recommandons l"introduction de la technique de comptage visuel par la méthode de la plongée marine, qui est utilisée en routine dans le cadre de l"évaluation des effets bio-écologiques des réserves marines (Micheli et al., 2004 ;Abesamis et al., 2006 ;Claudet et al., 2006). Annexes relatifs à la fonction de locomotion (Diversité fonctionnelle). ...
Thesis
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Titre : Étude du réseau trophique de l " aire marine protégée tropicale et estuarienne de Bamboung, Sine-Saloum : implications écologiques de la morphologie, richesse, abondance et biomasse des poissons.
... Abundance, body size, age, and recruitment of exploited fish species have been shown to increase within closed fishery areas (e.g., Halpern and Warner 2002;Lester et al. 2009;Hart and Rago 2006;McLean et al. 2011;Wen et al. 2013), and in surrounding areas through the spillover of larvae and adults (e.g., Russ 2002;Gell and Roberts 2003;Alcala et al. 2005;Abesamis and Russ 2005). However, there is considerable variation in recovery rate after closed areas are established (e.g., Williamson et al. 2004;Abesamis et al. 2006;Harmelin-Vivien et al. 2008;Russ et al. 2008;Russ and Alcala 2010), with Electronic supplementary material The online version of this article (doi:10.1007/s00267-015-0526-9) contains supplementary material, which is available to authorized users. some studies finding no effect on target fishery species (Mapstone et al. 2008;McLean et al. 2011). ...
Article
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This study examined whether a measured increase in average body size of adult sea scallops inside three fishery closed areas on Georges Bank (GB), United States (US), was sufficient to increase larval supply to closed areas and open fishing areas in both US and Canadian areas of the Bank. The effects of adult scallop density-at-size and fecundity-at-size on egg production were compared among open and closed fishery areas, countries, and time periods before and after the closed areas were established. Estimated egg production was then used to define spawning conditions in a coupled biological-physical larval tracking model that simulated larval development, mortality, and dispersal. Results showed that order of magnitude increases in larval settlement after closure were facilitated by increases in size-dependant egg production inside and dispersal from Closed Areas I and II, but not Nantucket Lightship Closed Area. The distributions of both egg production and larval settlement became more uniform across the Bank, causing the relative contribution of Canadian larvae to US scallop aggregations to decrease after establishment of Closed Areas I and II. Decreases in small and medium-sized scallop density in Canada and decreases in large scallops over the US-Southern Flank after closure caused local declines in egg production but were not sufficient to negatively affect larval settlement at the regional scale. Our model suggests that the establishment of fishery closed areas on GB considerably strengthened larval supply and settlement within and among several adult scallop aggregations.
... However, many MPAs are still fairly young, and the changes that may result from protecting areas are only recently becoming clear [5][6][7][8][9][10][11]. While the role of MPAs differs between locations and countries, MPAs are frequently used as an aspect of fisheries management to increase yields by facilitating recruitment to the population by providing refuge areas for individuals to reach sexual maturity and to increase the density of individuals in the surrounding area through either emigration of adults or larval dispersion [5,[12][13][14][15]. ...
Article
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Marine protected areas can be designated for a number of reasons, but exactly how they provide benefits is only recently being understood. We assessed the effect of protection on the size and distribution of six common species of grouper in a coral reef ecosystem. Data on live coral cover, coral genus diversity, and coral colony structure type were also compared to give an indication of reef quality between sites. A significant interaction was found for Aethaloperca rogaa and Cephalopholis nigripinnis, indicating that protected areas held greater numbers of smaller and median sized fish of these species than unprotected areas. Similar but nonsignificant trends were found for Cephalopholis miniata and Cephalopholis argus. For Anyperodon leucogrammicus, MPAs held significantly more fish than unprotected sites, but as the increase was equal between size categories there was no interaction. The last species Epinephelus fasciatus, which was one of the smallest species, had no significant interaction, similar mean counts between protected and unprotected areas, and no obvious strong favouritism for particular sites with values indicating better reef quality, indicating intraspecies competition. The results of this study indicate that while the MPAs in this study are likely too small to benefit large groupers, the improvements to habitat quality have indirect benefits to groupers, especially at their earlier life stages.
... The alternative conclusion reached in their study may reflect differences in the reef fish species targeted by fishers and their role in ecosystem functioning. For example, the removal of major groups of herbivores, such as those targeted in the Philippines (Abesamis et al. 2006), may increase the vulnerability of coral communities to phase shifts towards reefs dominated by algae (Bellwood et al. 2006), which are known to enhance dissolved organic carbon and stimulate microbial growth (Haas et al. 2011). However, such phase shifts have not been observed outside Philippine reserves (Stockwell et al. 2009). ...
Article
Parks and protected areas have been instrumental in reducing anthropogenic sources of damage in terrestrial and aquatic environments. Pathogen invasion often succeeds physical wounding and injury, yet links between the reduction of damage and the moderation of disease have not been assessed. Here, we examine the utility of no-take marine reserves as tools for mitigating diseases that affect reef-building corals. We found that sites located within reserves had four-fold reductions in coral disease prevalence compared to non-reserve sites (80,466 corals surveyed). Of 31 explanatory variables assessed, coral damage and the abundance of derelict fishing line best explained differences in disease assemblages between reserves and non-reserves. Unexpectedly, we recorded significantly higher levels of disease, coral damage and derelict fishing line in non-reserves with fishing gear restrictions than in those without gear restrictions. Fishers targeting stocks perceived to be less depleted, coupled with enhanced site access from immediately adjacent boat moorings, may explain these unexpected patterns. Significant correlations between the distance from mooring sites and prevalence values for a ciliate disease known to infest wounded tissue (r = -0.65), coral damage (r = -0.64) and the abundance of derelict fishing line (r = -0.85) corroborate this interpretation. This is the first study to link disease with recreational use intensity in a park, emphasizing the need to evaluate the placement of closures and their direct relationship to ecosystem health. Since corals are modular, ecological processes that govern reproductive and competitive fitness are frequently related to colony surface area, therefore even low levels of cumulative tissue loss from progressing diseases pose significant threats to reef coral persistence. Disease mitigation through reductions in physical injury in areas where human activities are concentrated is another mechanism by which protected areas may improve ecosystem resilience in a changing climate.
... It is therefore necessary to know where and in what quantity are to be found the habitats already known to play a nursery role (Cheminée et al. 2011), and furthermore which are the other habitats of the seascape mosaic of the rocky infralittoral that play a nursery role. In addition, it will be necessary to protect parts of the adult habitats, from which the fishing grounds may be resupplied with adults by spill-over effect (Abesamis et al. 2006;Grüss et al. 2011;Goni et al. 2008). Finally, it is also necessary to ensure that the nurseries are present in sufficient number and at the right distance from the adult habitats, in order to guarantee satisfactory connectivity between these habitats and enable ontogenic migration (Cheminée et al. 2011;Di Franco et al. 2012;Gillanders et al. 2003). ...
... Spillover occurs when individuals from within an MPA emigrate into adjacent areas open to fishing, while recruitment subsidy is the process by which larvae produced by large and fecund populations within MPAs are exported to neighboring reefs (Boersma & Parrish 1999, Russ et al. 2004, Gaines et al. 2010. Numerous studies have detected these processes occurring in reefs surrounding MPAs (Russ & Alcala 1996, McClanahan & Mangi 2000, Russ et al. 2003, Abesamis & Russ 2005, Abesamis et al. 2006, albeit often on spatial scales ranging only in the 100s of meters (Harmelin-Vivien et al. 2008). The potential of MPAs to promote increased abundance of fishery populations outside of their borders complicates the assessment of MPAs using adjacent reefs as contrast-ing experimental units because these areas are inherently altered by the establishment of nearby MPAs (Caselle et al. 2015). ...
Article
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Marine protected areas (MPAs) have become critical components of fisheries management programs worldwide. Despite their widespread usage, the performance of MPAs in sustaining fisheries remains debated, partially due to inconsistent results across studies. Here, we aim to standardize conclusions regarding MPA performance throughout the Philippines using a 'reef-wide' meta-analysis. This analysis uses pooled visual census data from 39 matched pairs of MPAs and fished reefs surveyed twice over a mean period of 3 yr, allowing for the comparison of abundance and demographic structure of fishes across both protected and fished areas over time. The meta-analysis revealed that (1) although fish density was higher inside MPAs within individual sampling periods, reef-wide fish density generally either increased or remained stable over time, and (2) reef-wide increases in large-bodied fish were evident between survey periods, indicating positive demographic shifts within both MPAs and adjacent areas. These results suggest that, over relatively few years of protection, MPAs in the Philippines are able to promote beneficial shifts in fish population structure throughout entire reef systems rather than simply maintaining stable populations within their borders. Demonstrating such benefits to adjacent reefs is critically important to the success of MPAs in the Philippines because compliance with closures of fishing grounds increases with realized benefits to fishing communities. The reef-wide framework of MPA assessment demonstrated in this study presents the advantages of including adjacent fisheries as integrated components when quantifying MPA performance, revealing trends that are indistinguishable when using spatial comparisons between MPAs and fished reefs.
... Their high mobility relative to the small size of many community-based NTMRs established in the Philippines (e.g., 5-30 ha; Weeks, Russ, Alcala, & White, 2010) would suggest high flux rates across NTMR boundaries and thus reduced probability of clear increases in density due to NTMR protection (Abesamis, Russ, & Alcala, 2006;DeMartini, 1993). ...
Article
The effects of no-take marine reserve (NTMR) protection and changes in benthic habitat on fusiliers (family Caesionidae) were investigated at four small Philippine offshore islands on time scales of 10–31 years. Fusiliers are highly mobile, schooling, medium-sized planktivorous fish that generally feed “off-reef.” For these reasons, and given the small size of the NTMRs (3.6–37.5 ha) in this study, it was predicted that fusilier density would be unlikely to show clear effects of NTMR protection, or to respond to changes in benthic habitat. In contrast to predictions, clear NTMR effects were observed on fusilier density at three of the four NTMRs, with durations of protection from 14 to 31 years. Furthermore, the study provided strong evidence that benthic variables, specifically cover of live hard coral and dead substratum, affect the density of fusiliers. This effect of benthic habitat on density was highlighted by several major environmental disturbances that caused shifts in the benthic habitat from live hard coral to dead substratum. For two of the three most abundant species of fusiliers individually, and for all three of them combined (Pterocaesio pisang + Caesio caerulaurea + Pterocaesio digramma/tessellata), as live hard coral cover decreased, fish density decreased. It is hypothesized that these “off-reef” daytime feeders may have such a strong association with live hard coral cover because they use this habitat as nocturnal sleeping sites. Multivariate analyses indicated that, across all sites and times sampled, cover of live hard coral and dead substratum accounted for 38% of the variation in fish assemblage structure. These results are important as there are very few reports in the published literature of strong effects of NTMR protection or changes in benthic habitat on the density and assemblage structure of fusiliers.
... Documented evidence of the effectiveness of sanctuary zones subject to appropriate compliance is common in the literature (e.g. Abesamis et al., 2006;Russ et al., 2008), yet there is little evidence presented here to suggest that the abundance of targeted fish is higher in sanctuary zones sampled at Ningaloo. This may be due to the relatively small number of sampling sites currently included into the presented data, with the effects of spatial fishing restrictions often being subtle in nature (Wilson et al., 2012). ...
Technical Report
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This report presents a synthesis of ecological monitoring within the Ningaloo marine reserves up to the end of 2016. The work presented here is managed by the Department of Biodiversity, Conservation and Attraction’s (DBCA) Marine Science Program (MSP) as part of Science Project Plan 2012/008 and is implemented in collaboration with DBCA Exmouth District staff and with additional information provided by the Department of Primary Industries and Regional Development (DPIRD) and the Bureau of Meteorology (BoM). Detailed information on the condition of and pressures acting on four of the park’s six ecological/physical value Key Performance Indicators (KPIs) are presented, being: • Water quality • Finfish communities • Coral reef communities • Mangrove communities The main risk to ecological values within the reserves currently relates to coral reef communities. The condition of corals at shallow water monitoring sites within the reserves has declined since 2010. Declines have been most severe in the eastern sector, whilst the southern sector has suffered less dramatic but continued losses. The northern sector in comparison has remained relatively stable. The primary cause of the coral loss has been thermal stress caused by increasing sea water temperature, with anomalously high summer temperatures between 2011 and 2013 causing a majority of the loss. The abundance of targeted fishes has been relatively stable across the limited monitoring period. However, there is some concern that the abundance of the heavily fished spangled emperor (Lethrinus nebulosus) is currently low in relation to historical observations. There have been widespread declines in the abundance of corallivorous fishes throughout the park, most likely driven the loss of coral described above. The spatial extent of mangroves at Mangrove Bay increased between 2006 and 2014. However, recent observations indicate signs of declining condition, associated with sedimentation from a flooding event in 2014 and declining sea level caused by the regional influence of the Southern Oscillation Index cycle.
... Only 1% of all the groupers caught in Kenya [27] and 10% in Seribu Islands, Jakarta, is the slender grouper [33], while in Kotania Gulf, Maluku, the fish is the least caught grouper [6]. The slender groupers live at the bottom of the coral reefs [34], making them rarely caught by the fishers' handlines. According to [12], the fish lives in 5-80 m deep waters, and therefore not all the fishers' handlines are able to catch them. ...
Article
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Arafura Sea is rich in its resources, e.g. shrimp, pelagic fish, demersal fish, and coral reef fish. Coral reef fish commonly found in Arafura waters are among others brown-marbled grouper, slender grouper, leopard coral grouper, humpback grouper, etc. One of the groupers that has a higher selling price than the other groupers is slender grouper ( Anyperodon leucogrammicus) . The high demand for the fish is in line with the increase in the catch and the exploitation status. Therefore, a study is necessary to analyze the exploitation status of the slender grouper in Arafura Sea. This study was carried out from March to November 2017 by sampling the grouper at its landing site in Dobo, Aru Islands, from the fishing grounds in Arafura Sea, Maluku. The size of the slender grouper was 15–120 cmTL, and its growth pattern was allometric negative. Its growth rate (K) was 0.34 per year and its fishing mortality (F) was higher than the natural mortality (M). The exploitation rate (E) of the fish was 0.52%, meaning the fish was already moderately exploited. Therefore, precautionary managements are necessary to maintain the sustainability of the slender grouper resources in Arafura Sea.
... Among published essays of populations near NTAs [10,[29][30][31][32][33], increased fish populations have rarely been attributable to spillover more than 1 km out from an NTA boundary. Due to the popular practice of over-fishing of large predator fish [14] near the boundary ∂Ω of an NTA with domain Ω, the boundary condition may be approximated as the idealised Dirichlet condition ...
... Among published essays of populations near NTAs [10,[29][30][31][32][33], increased fish populations have rarely been attributable to spillover more than 1 km out from an NTA boundary. Due to the popular practice of over-fishing of large predator fish [14] near the boundary ∂Ω of an NTA with domain Ω, the boundary condition may be approximated as the idealised Dirichlet condition ...
Article
Sustainable natural resource management strategies are required to maintain a fishery. One common device is to designate a No-Take Area (NTA) or a less restrictive Marine Protected Area (MPA) within a fishery. In this work, exact time-dependent solutions to 2-D nonlinear reaction-diffusion equations of Fisher type are constructed to model the fish population density of a single species within an NTA. The spillover rate from an NTA, important for harvesters, has previously been calculated without allowing for spatial variation within the NTA. Here, that spatial dependence is incorporated in the calculation. Spatially-dependent and density-dependent diffusivity and birth rates are considered for linear, rectangular and circular geometries, the latter being the most efficient with minimal critical domain area. The effect of the spatial dependence of diffusivity and birth rates, common in fish populations where reproduction and protection are favoured towards the centre, on the minimum size of an exclusion zone that ensures species survival, is studied. It is shown that when any one of these factors is taken into account, the size of the critical domain decreases by a small amount.
... Lethrinidae and Carangidae are generally less territorial than Serranidae or Lutjanidae species (Kaunda-Arara and Rose, 2004;Kulbicki et al., 2005) and Scombridae are highly vagile species able to cross MPA boundaries (Abesamis et al., 2006). A larger home range would allow movements towards preferred environmental conditions. ...
Article
Carnivorous fish are a key part of the Indonesian human population sustenance, and it is important to design marine protected areas that include environmental features that allow these species to thrive. Many studies report the role of coral cover and habitat complexity in determining fish distribution on coral reefs but broader environmental factors such as current velocity and productivity are less studied. Southern Indonesia is characterised by upwellings and strong currents, stemming from the tidal cycle and the Indonesian Throughflow. In this study we investigate how current velocity, chlorophyll-a (chl-a), sea surface height and temperature and relate to the biomass of carnivorous fish, considering the influence of habitat complexity and coral cover. Data were collected by surveying seven sites around Nusa Penida MPA for a total of 97 h of observation. Serranids and Lutjanids showed higher dependency on coral cover than fish from family Lethrinidae, Carangidae and Scombridae for which current, sea surface height, chl-a, and temperature were more influential predictors. Considering the similar trophic ecology of these species, the different relationship with oceanographic factors is likely related to different body shapes, living, and feeding habits between fish families. Changes in sea surface temperature and current velocity induced by vertical mixing are affecting coral reef fisheries-targeted species distribution in Nusa Penida and investigating these relationships on a broader scale will better inform marine spatial planning decisions.
... Spillover is purely densitydependent, that is, biomass flows depend upon relative population densities (Sánchez Lizaso 2000; Abesamis and Russ 2005). Frequency-dependent models predict that as rising density affects species fitness and increases competition between individuals for resources, it triggers a movement/transfer of individuals/biomass towards adjacent (fished) areas with lower population densities (Sánchez Lizaso 2000;Kramer and Chapman 1999;Abesamis et al., 2006;Lorenzo et al., 2015). ...
Article
The study assesses the conservation and fisheries benefits of the Blue Bay Marine Park in Mauritius. It addresses the question - are the higher catch rates near the Park a result of population spillovers or of reduced fishing effort in those waters due to site-specific attributes? There is no data on catches and fishing effort prior to the reserve's establishment; a bioeconomic model is used to separate the effects of spillover and effort redistribution on catch rates in waters next to the Marine Park. The area's fish populations are replicated using a dynamic age-structured model with a Beverton-Holt recruitment function, while fishing effort is predicted using a random utility model and Random Parameter Logit estimation. The bioeconomic model is characterised by two-way feedback loops between fish stocks and the geographic redistribution of fishing effort. A comparison of fish population, biomass, and catch rates in the fisheries with and without effort redistribution, suggests that the reduced fishing effort in waters near the Park, rather than spillover, is driving the increase in observed catch rates. Travel distance, variation in catch rates, depth of water and area status (lagoon vs. off-lagoon) explain the relocation of fishing effort away from the adjacent of the marine park. The study shows how site-specific characteristics affecting fisher behaviour are important in the design of marine reserves.
... Typhoon impact was identified by relating reef aspect to typhoon path and through consultation with local stakeholders (McClure et al. 2020). A habitat complexity index (HCI) from 1 to 50 was computed by combining estimates of live hard coral cover, structural complexity, and reef slope following Abesamis et al. (2006), whereby HCI=(proportion of live hard coral cover + 1) × (mean structural complexity + 1) × (mean reef slope + 1). Island variables were estimated for each sampled NTMR and fished area (Table 1). ...
Article
Understanding whether assemblages of species respond more strongly to bottom-up (availability of trophic resources and/or habitats) or top-down (predation pressure) processes is important for effective management of resources and ecosystems. Here, we determine the relative influence of environmental factors and predation by humans in shaping the density, biomass and species richness of four medium-bodied (10-40cm total length; TL) coral reef fish groups targeted by fishing (mesopredators, planktivores, grazer/detritivores, scrapers), and the density of two groups not targeted by fishing (invertivores, small fish ≤10cm TL) in the central Philippines. Boosted regression trees were used to model the response of each fish group to 21 predictor variables: 13 habitat-level, 5 island-level, and 3 fishing variables; no-take marine reserve (NTMR) presence/absence, size, and age. Targeted and non-targeted fish groups most strongly responded to habitat-level, then island-level variables, with fishing (NTMR) variables having lesser effects. Of the habitat-level variables, live hard coral cover and structural complexity (or a habitat complexity index), and depth had the greatest effect on the density, biomass and richness of targeted fish groups, and density of non-targeted fish groups, with proximity to the nearest river, and island elevation the most influential island-level variables of fish groups. NTMRs were influential only on fishes targeted by fishing, with NTMR size positively correlated with density, biomass and species richness of targeted fishes, particularly mesopredatory and grazing/detritivorous fishes. Importantly, NTMRs as small as 15 hectares showed positive effects on the medium-bodied fish groups. This finding provides reassurance for regions that have invested in small-scale community-managed NTMRs, often following a history of high fishing pressure. However, management strategies that integrate sound coastal land-use practices to conserve adjacent reef fish habitat, with strategic NTMR placement, and the implementation of larger NTMRs, will be crucial for maintaining biodiversity and fisheries. Article Impact Statement: Prioritizing strategic land-sea management that protects habitat for coral reef fishes will support biodiversity and fisheries. This article is protected by copyright. All rights reserved.
... Despite the high potential of fishing pressure outside the MPA, biomass and size of groupers and snappers were larger outside, rather than inside. Spillover could occur, but it is only assumed if related to higher numbers and biomass inside (Abesamis, Russ, & Alcala, 2006;Gell & Roberts, 2003). These individuals may move between different habitats or depths (Claro & Parenti, 2001;Farmer et al., 2011;Goldstein, D'Alessandro, & Sponaugle, 2016;Herbig et al., 2019;Tupper & Rudd, 2002;Valdés-Muñoz & Mochek, 2001), and possibly momentarily benefit from protection within the MPA with opportunity to grow. ...
Article
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Cuba has been leading marine protected area (MPA) designation in the Caribbean region to ensure conservation of its valuable marine ecosystems. Yet, an efficient monitoring program for MPAs is still to be implemented and will benefit from pre-existing information. The highly regulated MPA of Punta Francés National Park is one of the first Cuban MPAs and was established mainly to protect species and ecosystems for tourism purposes. Monitoring of protection effects on commercial fish species was lacking in this MPA. This study aimed at increasing local scientific knowledge by providing a baseline study about the most commercially fished families (Haemulidae, Lutjanidae and Serranidae) around Punta Francés MPA. Data collected represent only a limited period but can be used as a base point to support future monitoring. Fish abundance in number and biomass, and size were collected to test for differences between inside and adjacent areas outside the Punta Francés MPA, in different coral reef types. The main result of this study was the significantly larger size and biomass of snappers and groupers outside the MPA where intense fisheries occur. An observation consistent with a large spawning aggregation was also recorded outside the MPA. Even with a limited set of data, these results suggest that, at least temporarily, the most targeted species [and sizes] are still highly vulnerable to fisheries. Relevant habitats in the adjacent area, that are apparently missing within the MPA, may support some of the results found. Extending the limits of the Punta Francés MPA to include those habitats outside may be critical to ensure the effectiveness of this MPA in contributing to protect the most commercial species of the region. This should be done together with efficient fisheries management measures in the region, such as the significantly increase of minimum legal sizes and temporal closures during spawning migrations.
... Aware that marine biodiversity is threatened by overfishing and climate change, the implementation of marine protected areas (MPA) has been proposed as alternative solution [1][2][3][4][5][6] The government of Senegal committed to implement a network of marine protected areas, with a goal of encompassing 10% of its seas and coastal areas within an effectively managed, ecologically representative and well-connected system of MPA by 2020. Therefore, five MPA (Saint-Louis, Cayar, Joal-Fadiouth, Bamboung and Abene MPA) were implemented in 2004 and two in 2014 (Sangomar and Gandoule MPA). ...
... Indirect effects of fishing on non-target species may not be evident in assemblage-level abundance and diversity indicators. While fishing may disrupt food webs (Pauly et al. 2000), there are cases where fishing effects and the benefits of protection were limited to target species even under intense exploitation (Jennings & Kaiser 1998, Abesamis et al. 2006. Restricting the removal of large piscivores potentially increases the predation of juveniles and small fishes (Polunin & Roberts 1993, Daan et al. 2005, Olds et al. 2012. ...
Article
No-take reserves (NTRs) have been effective at conserving fish assemblages in tropical systems such as coral reefs, but have rarely been evaluated in turbid tropical estuaries. The present study evaluated the effect of a mangrove NTR on the conservation of juvenile fish abundance, commercial fish biomass and biodiversity at the assemblage level; and the abundance of juveniles, target and non-target adults at the family level. The evaluation incorporated one aspect of seascape connectivity - proximity to the sea, or in this case, the Gulf of Paria. Linear mixed models showed that the NTR had a positive effect only on species richness at the assemblage level. However, juvenile fish abundance, commercial fish biomass, taxonomic distinctness and functional diversity were not enhanced in the NTR. The inclusion of connectivity in these models still failed to identify any positive effects of the NTR at the assemblage level. Yet, there were significant benefits to juvenile fish abundance for 5 of 7 families, and for one family of non-target adults. Possible explanations for the limited success of the NTR to fish assemblages include failing to account for the ecology of fish species in NTR design, the drawbacks of ‘inside-outside’ (of the NTR) experimental designs, and the fact that fishing does not always impact non-target species. It is important to recognise that mangrove NTRs do not necessarily benefit fish assemblages as a whole, but that finer scale assessments of specific families may reveal some of proclaimed benefits of NTRs in tropical estuaries.
... Regarding the MPAs size, there has been a continuum debate concerning meta-population theory about the benefits of a single large or several small (SLOSS) protected areas in conserving biodiversity in a fragmented habitat over the long term (Wilcox and Murphy 1985). While large MPAs may support larger landscapes and populations, reducing edge effects , well inter-connected networks of smaller MPAs can support the persistence of populations at a greater extent (Zhou and Wang 2006) and maximize spill-over of propagules across the edges (Abesamis et al. 2006). As for MPAs shape, it should maximize the inclusion of targeted landscapes or habitats, and capture the gradient from onshore-offshore or habitat-habitat shifts of species of interest (IUCN-WCPA 2008). ...
... Aware that marine biodiversity is threatened by overfishing and climate change, the implementation of marine protected areas (MPA) has been proposed as alternative solution [1][2][3][4][5][6] The government of Senegal committed to implement a network of marine protected areas, with a goal of encompassing 10% of its seas and coastal areas within an effectively managed, ecologically representative and well-connected system of MPA by 2020. Therefore, five MPA (Saint-Louis, Cayar, Joal-Fadiouth, Bamboung and Abene MPA) were implemented in 2004 and two in 2014 (Sangomar and Gandoule MPA). ...
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This work is a preliminary comparative study of fish assemblage between a marine protected area where fishing is banned in Joal-Fadiouth (JFMPA) and a fishing authorized marine protected in Cayar (CMPA). It consisted of seasonal sampling between 2015 and 2016. Trophic classification based on food regime was performed in order to describe the fish fauna of these MPA. Multivariate analysis like factorial correspondence analysis and hierarchical classification analysis were carried out to study the spatial differences of fish assemblages. Both MPA had similar number of species, 103 fish species belonging to 45 families. However, a fundamental difference in terms of fish composition, abundance and biomass were noted. Only 38 fish species were shared by these MPA. In other words, among the 103 fish species found in CMPA 65 were not encountered in JFMPA. The total number of individuals in JFMPA was six time higher, and the biomass in JFMPA was triple of that in CMPA. The fish assemblage of CMPA was dominated in terms of abundance by two second-level predators Pagellus bellottii and Galeoides decadactylus (12.4%), while in JFMPA the pelagic herbivores Ethmalosa fimbriata (34%) dominated the fish assemblage. Our results suggest that management strategy in JFMPA seem to be more efficient than that of CMPA. Therefore, fishing activities in CMPA, even controlled seem to have negative effect on fish abundance.
... The level of response is partly influenced by the level of pressure applied (e.g. collecting, fishing, environmental disturbance, etc.) prior to establishment of 'no take' areas, and the ongoing pressure on the areas with which they are being compared (Abesamis et al., 2006;Mapstone et al., 2004;Russ and Alcala, 1998). Highly targeted species are likely to respond to suitable spatial protection. ...
Article
The influence of ‘no take’ Marine Protected Areas (MPAs) on abundance and size of fishes varies considerably and the likely benefits are still debated. Meta-analyses reveal findings are biased towards studies in shallower depths suitable for diving surveys. Empirical comparisons in deeper waters, including among areas with differing spatial management, further contribute to understanding of MPA benefits and constraints. We compare length and abundance of commercially and recreationally targeted fishes (and bycatch) among management types within and adjacent to the Solitary Islands Marine Park (SIMP), Australia. Sampling was done on reefs between 25 and 40 m depth in ‘no-take’ and fished ‘partially protected’ areas within the marine park and fished areas outside the SIMP, using stereo- Baited Remote Underwater Videos (stereo-BRUVs) at eight, nine, thirteen and fourteen years after these ‘no take’ areas were established. Four species targeted by fishers: snapper Chrysophrys auratus, grey morwong Nemadactylus douglasi, pearl perch Glaucosoma scapulare, and venus-tuskfish Choerodon venustus, were more abundant and larger in ‘no take’ zones overall and showed an increase through time in ‘no take’ relative to both types of fished area. In contrast, there was no distinct pattern of four bycatch species increasing in abundance in ‘no-take’ areas. Abundances of fish in partially protected areas were similar to fished areas outside the MPA. This study adds empirical evidence to the assertion that ‘no take’ areas in particular, can contribute to both marine conservation and natural resource management.
... bluegill) owing to increased potential food availability. As nest-site fidelity is highly correlated with reproductive success in largemouth bass, coupled with relatively small home range sizes for both largemouth bass and bluegill (<250 m 2 for bluegill, and <1 km 2 for largemouth bass; Fish & Savitz, 1983;Ahrenstorff et al., 2009), relief from targeted fisheries pressure over time could allow for a greater proportional abundance of both species within the FPA, and also within the bordering transition zone as a result of densitydependent spillover (Abesamis, Russ, & Alcala, 2006;Halpern, Lester, & Kellner, 2010). ...
Article
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Research has identified numerous conservation benefits attributed to the use of marine protected areas (MPAs), yet comparatively less is known about the effectiveness of freshwater protected areas (FPAs). This study assessed multiple long‐standing (>70 years active) intra‐lake FPAs in three lakes in eastern Ontario, Canada, to evaluate their potential conservation benefits. These FPAs were intended initially to protect exploited populations of largemouth bass (Micropterus salmoides (Lacépède, 1802)), but since their establishment no empirical data have been collected to evaluate the effectiveness of FPAs for protecting bass or the broader fish community. A comparative biological census of fish species abundance, biomass and species richness was conducted using snorkelling surveys within FPAs, along the bordering transition zones, and in more distant non‐protected areas of the lake that had similar habitats to the FPAs. In general, the FPAs yielded benefits that were most obvious (in terms of abundance and biomass) for the focal protected species (i.e. largemouth bass) as well as several shiner species. Largemouth bass and shiner abundance and biomass were highest in the FPA, lowest in the distant non‐protected areas, and intermediate in the transition zone. Species richness was also highest in the FPAs in two of the three lakes. Collectively, these results support the use of FPAs as a viable and effective conservation strategy that extends beyond simply limiting the exploitation of a target species. Beyond the benefits afforded to fish within the FPA, evidence of spillover in adjacent areas was also observed, which is promising. Additional research is needed on the effectiveness of FPAs in a variety of regions and water‐body types facing various threats in an effort to understand when, where and how to best use FPAs to benefit aquatic biodiversity.
... Clade 4-7 is distinctly made up of mostly squid haplotypes detected around the island of Panay, with small contributions from populations around Negros (haplotypes 21, 22, 23, and 33, Figure 2). This indicates that populations may have been fragmented due to the result of geologic activity in the region, seasonal changes in currents, or even modern-day commercial fishing management, which have all been shown to influence fragmentation of marine habitats in the area (Abesamis, Russ & Alcala, 2006;Huang, Wu, Zhao, Chen & Wang, 1997;Savina & White, 1986;Wyrtki, 1961;Zhou, Ru & Chen, 1995). Habitat fragmentation was also inferred within clades 2-11 and 3-1 (Table 4) (Table 4), suggesting that the alternating direction of prevailing currents in the region is one mechanism of dispersal as well as isolation for these squids. ...
Article
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Abstract Marine microbes encounter a myriad of biotic and abiotic factors that can impact fitness by limiting their range and capacity to move between habitats. This is especially true for environmentally transmitted bacteria that cycle between their hosts and the surrounding habitat. As geologic history, biogeography, and other factors such as water temperature, salinity, and physical barriers can inhibit bacterial movement to novel environments, we chose to examine the genetic architecture of Euprymna albatrossae (Mollusca: Cephalopoda) and their Vibrio fischeri symbionts in the Philippine archipelago using a combined phylogeographic approach. Eleven separate sites in the Philippine islands were examined using haplotype estimates that were examined via nested clade analysis to determine the relationship between E. albatrossae and V. fischeri populations and their geographic location. Identical analyses of molecular variance (AMOVA) were used to estimate variation within and between populations for host and symbiont genetic data. Host animals demonstrated a significant amount of variation within island groups, while symbiont variation was found within individual populations. Nested clade phylogenetic analysis revealed that hosts and symbionts may have colonized this area at different times, with a sudden change in habitat. Additionally, host data indicate restricted gene flow, whereas symbionts show range expansion, followed by periodic restriction to genetic flow. These differences between host and symbiont networks indicate that factors “outside the squid” influence distribution of Philippine V. fischeri. Our results shed light on how geography and changing environmental factors can impact marine symbiotic associations at both local and global scales.
... It has been documented that home range and mobility tends to be positively correlated with body size (Harestad and Bunnel 1979;Kramer and Chapman 1999;Nanami 2015). The movement patterns of our species are described as vagile for H.varius (Abesamis et al. 2006), and roving grazers for S.vulpinus and Z.scopas . Little infomration is available on their specific home range distances; however, information on a number of species within their families with similar body sizes indicate linear home ranges spanning 0.016 to 0.65 km (Table 1). ...
Article
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It is being increasingly recognized that small coral reef fishes are highly specialised on branching coral substrata and are threatened by reef degradation. In the past, it has been assumed that medium-sized mobile coral reef fishes may be less at risk. This assumes medium-sized mobile fishes are not as equally associated with and susceptible to the loss of live coral, especially early in their ontogeny. Here we use observations of habitat use and compositional analysis to show that three mobile medium-sized fishes, Siganus vulpinus (Siganidae), Zebrasoma scopas (Acanthuridae) and Heniochus varius (Chaetodontidae), are associated with live coral substrata early in ontogeny and less so as adults on coral reefs in Kimbe Bay, Papua New Guinea. Small size classes of S. vulpinus and Z. scopas showed a preference toward using branching and bushy live coral, as well as structurally intact dead coral, suggesting an underlying importance of reef structural complexity during early life stages. H. varius was associated with foliose and plate coral through all size classes, but selectivity declined as sub-adults and adults. In general, all species became more generalist in their use of reef substrata at larger sizes, but S. vulpinus and Z. scopas tended to avoid open and less structurally complex reef habitats, such as, sand, soft corals and sponges, while H. varius avoided dead coral substrata. Our results confirm that juvenile stages may be a critical bottleneck that exposes medium-sized reef fishes to the same risks small reef fish species experience due to declining coral cover. Link to full text: https://rdcu.be/bf1pZ
... Unlike well-documented examples of spillover effects from marine protected areas (Roberts et al. 2001;Abesamis et al. 2006;Russ & Alcala 2011), reported examples of spillover effects from terrestrial conservation reserves are uncommon. Tanentzap and Lloyd (2017) recorded a spillover effect created by a fenced reserve in New Zealand, where birds protected inside the sanctuary bred and dispersed outside. ...
Article
Spillover effects are an expansion of conservation benefits beyond protected areas through dispersal of species that reside within. They have been well documented in marine but not terrestrial systems. To understand the effects on wildlife created by conservation fences, we explored the internal and external gradients of activity in mammal, reptile, and bird species at a conservation reserve in arid Australia that is fenced to exclude invasive rabbits (Oryctolagus cuniculus), cats (Felis catus), and foxes (Vulpes vulpes). Two methods were used: counts of animal tracks along transects on sand dunes and captures at pitfall‐trapping sites. In both cases, sites were spaced at different distances from the reserve fenceline inside and outside the reserve. We recorded a range of spillover, source‐sink, step, and barrier effects that combined to create a zone within and around the reserve with fence‐induced species‐specific wildlife gradients. Two endemic rodents but none of the 4 mammal species reintroduced to the reserve showed positive spillover effects. Barrier effects, where activity was highest close to the fence, were recorded for the feral cat and native bettong (Bettongia lesueur), species that could not breach the fence. In comparison, some reptiles and native mammal species that could permeate the fence displayed source‐sink effects; that is, their activity levels were reduced close to the fence likely due to constant emigration to the side with lower density. Activity of some reptiles was lowest at core sites in the reserve and increased as distance toward the outside increased, a gradient likely related to trophic cascades triggered by predator exclusion. Our result show that fenced reserves can create overlapping layers of species‐specific gradients related to each species’ ability to permeate the fence and its varying susceptibility to threats. Managers should be aware that these gradients may extend for several kilometers either side of the fence and that not all contained species will increase in abundance. Creating wider conservation benefits may require increased fence permeability and threat reduction outside the fence. This article is protected by copyright. All rights reserved Article impact statement: Conservation fences create species‐specific internal and external wildlife gradients that don't always generate positive conservation benefits.
... On the contrary, the management levels of most of the MPAs in our study were still at level 0 or have not been assessed at all at the time of the study. There are also studies which showed increased in fish biomass in small locally managed MPAs after decades of strict enforcement (Russ and Alcala, 2003;Abesamis et al., 2006) but these are rather exceptional cases as most of the MPAs in the country are not effectively managed (Arceo et al., 2008;Maypa et al., 2012;PhilReefs, 2014). ...
Article
The Philippines has more than 1600 locally managed marine protected areas (MPAs), the most in the world. However, their effectiveness for coral reef fisheries management is often questionable because most of these MPAs are small and ineffectively managed. In this study, we assessed the fish biomass of commercially important coral reef fishes (e.g. surgeonfish (family Acanthuridae), parrotfish (subfamily Scarinae), snapper (family Lutjanidae), grouper (subfamily Epinephelinae), sweetlips (family Haemulidae), goatfish (Mullidae) and emperor (family Lethrinidae)) in 57 locally managed MPAs in the Philippines. We used the fish biomass level at the nationally managed, large (332.0 km2), remote, old and well enforced (i.e. strictly protected for >20 years) Tubbataha Reefs National Marine Park (TRNMP) as a proxy for “unfished” ecosystems (Bo). We considered fish biomass levels between 25 and 50% of Bo as biomass within the maximum sustainable yield for multi-species coral reef fisheries (BMMSY) (McClanahan et al., 2014). Results showed that fish biomass levels in 7%, 25% and 68% of the surveyed MPAs were “above BMMSY”, “within BMMSY” and “below BMMSY”, respectively. None of the reefs outside MPAs was “above BMMSY”. About 86% were “below BMMSY” and the rest of the 14% of the sites outside MPAs were “within BMMSY” (14%). The mean (±S.E.) fish biomass levels on reefs inside and outside MPAs were only about 20.4 ± 2.2% and 10.9 ± 1.3%, respectively, of the TRNMP level. Neither size nor age of MPAs was significantly associated with fish biomass. Overall, our study showed that the current locally managed MPAs are not effective enough for coral reef fisheries management but, nonetheless, better than having no MPA at all.
Article
Meta-analyses of disparate studies suggest that size and age of a 'no-take’ area (marine sanctuary) can influence its ecological response to protection. Few studies, however, have been designed explicitly to test how these factors influence the abundance trajectories of key species within sanctuaries.Diver surveys on reef habitat were conducted within a subtropical marine park in eastern Australia, to test for differences in abundances of targeted fishes between sanctuaries differing in size and age and compared with fished zones. Four management zones were sampled: (i) small sanctuaries established 1991 (<15 ha of reef and <200 m wide); (ii) large sanctuaries established 2002 (>100 ha of reef and > 500 m wide); (iii) zones which allowed recreational fishing but not commercial fish trapping (>200 ha of reef); and (iv) zones which allowed both recreational fishing and commercial fish trapping (>200 ha of reef). Multiple sites in each management zone were sampled for selected taxa eight times during the austral winter from 2002 to 2012.Many of the targeted taxa examined were more abundant in large sanctuary sites within a few years of the establishment of protection compared with the small sanctuary sites and the fished sites. Red morwong Cheilodactylus fuscus increased in large sanctuaries but were more abundant in the older smaller sanctuaries throughout the study. Similar increases were not observed in fished zones. There was considerable variability among years not associated with management type, including a peak in abundance for several species in 2005 and reduced abundance of many taxa following a destructive storm in 2009.This study provides strong empirical evidence that size and age of ‘no take’ areas are important for fish, and indicates that larger sanctuaries can rapidly reach levels of fish abundance similar to smaller older sanctuaries. Copyright © 2015 John Wiley & Sons, Ltd.
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The performance of two marine protected areas (MPAs) in Samal Island, Coral Garden and Aundanao MPAs were evaluated after more than 10 years of exis­ tence. The evaluation tools used were fishery dependent (i.e. focus group discussion) and independent (i.e. fish census, benthic assessment and crown­of­thorns density) samplings. All sampling was conducted at least twice for one year. In all sites, COTs densities were just above the alarming stage (~1 individual.250 m−2). Aundanao MPA showed a positive feedback system by supporting the spillover effect. There is high density of sexually mature fish (<30 cm Total length and significantly higher fish biomass estimates of target species (16 mt km) inside than outside the MPA. The relatively small catch (20 mt.year−1) from fishing adjacent to the MPA is attributed to the limited capacity of the core zone (only 3 ha) to support the fishery. It also serves as a refuge site for small pelagic fishes (i.e. ox-eye scad, Selar boops) that aggregate along the slope. In contrast, the Coral Garden MPA had very low fish biomass (4.0 mt km −2) and only a couple of sexually mature individuals both inside and outside the sites. Intermittent guarding which have resulted to occasional poaching in the no­take area was one of the reasons. Further, a newly introduced fishing gear bintol (modified lift net), for subsistence targeting damselfishes has started to operate near the area. This is an evidence of a lesser density of targeted food fish to catch. Coral Garden MPA has shown that the rate of extraction exceeded the pre­sumed turnover rate of the associated reef fish standing stock suggesting an overfishing of the area.
Article
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Ecosystems are under increasing pressure from external disturbances. Understanding how species that drive important functional processes respond to benthic and community change will have implications for predicting ecosystem recovery. Herbivorous fishes support reefs in coral-dominated states by mediating competition between coral and macroalgae. Spatiotemporal variability in herbivore populations and behaviour have direct effects on the removal of algae, but knowledge of how different drivers impact on herbivore populations and their foraging is currently lacking. Such knowledge is important to understand whether herbivory is likely to compensate for changing resource availability, and thus, the potential for reefs to recover from disturbance. The relative importance of these drivers has implications for the suitability of specific management actions put in place to support herbivory. Variability in density, body size, foraging movements and grazing rate of 2 parrotfish species was investigated across reefs exhibiting a range of benthic and fish community compositions. Foraging movements were influenced by the benthos, with foraging distances greatest on degraded reefs. In contrast, parrotfish densities were driven by the management status of the reef; parrotfish size was primarily linked to species identity, whereas grazing rate was influenced by both management status and species. These findings suggest that the distribution of foraging effort will vary over time in response to reef condition, such that feeding becomes more dispersed as reefs degrade. Gear restrictions that protect large, high-grazing-rate species, or designation of no-take areas, are likely to maximise algal removal, regardless of reef condition.
Article
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Herbivory, together with seasonal variations in temperature, light and nutrient concentration regulate macroalgal populations on coral reefs. Individual management interventions can influence this balance by altering some, but not all of these potential drivers. For example, no-take marine protected areas (MPAs) on coral reefs can increase herbivorous fish abundance, thereby decreasing macroalgal coverage, but have limited influence on water quality and other vagile drivers. We compared the relative influence of seven abiotic water quality variables to that of MPA status on macroalgal coverage in 14 sites (5 of which are within no-take MPAs) over four consecutive seasons (summer through to spring) within the marginal coral reef habitats of Moreton Bay, Australia. Algal cover was quantified by taking 100 photo quadrats per site per sampling with the relative importance of our eight factors determined statistically by generalised additive models. Overall, temporal variations in total macroalgal cover and four out of five important macroalgal genera correlated with factors other than marine protection, especially water temperature, salinity, water clarity (Secchi disc) and nutrient concentration (nitrogen and phosphorus). However, seasonal variations in cover of individual macroalgal genera did not follow strong temporal trends and were not consistent with total macroalgal cover, meaning that different factors were significant for different algal genera. Consequently, we advocate for caution in determining the influence of impact gradients by exclusively measuring total macroalgal cover. This study highlights the importance of considering local impact gradients and habitat recovery processes in the design of protected area networks.
Article
Overfishing may seriously impact fish populations and ecosystems. Marine protected areas (MPAs) are key tools for biodiversity conservation and fisheries management, yet the fisheries benefits remain debateable. Many MPAs include a fully protected area (FPA), restricting all activities, within a partially protected area (PPA) where potentially sustainable activities are permitted. An effective tool for biodiversity conservation, FPAs, can sustain local fisheries via spillover, that is the outward export of individuals from FPAs. Spillover refers to both: “ecological spillover”: outward net emigration of juveniles, subadults and/or adults from the FPA; and “fishery spillover”: the fraction of ecological spillover that directly benefits fishery yields and revenues through fishable biomass. Yet, how common is spillover remains controversial. We present a meta‐analysis of a unique global database covering 23 FPAs worldwide, using published literature and purposely collected field data, to assess the capacity of FPAs to export biomass and whether this response was mediated by specific FPA features (e.g. size, age) or species characteristics (e.g. mobility, economic value). Results show fish biomass and abundance outside FPAs was higher: (a) in locations close to FPA borders (<200 m) than further away (>200 m); (b) for species with a high commercial value; and (c) in the presence of PPA surrounding the FPA. Spillover was slightly higher in FPAs that were larger and older and for more mobile species. Based on the broadest data set compiled to date on marine species ecological spillover beyond FPAs' borders, our work highlights elements that could guide strategies to enhance local fishery management using MPAs.
Book
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This book describes as fully as possible each of the 564 no-take marine reserves in the Visayas. It also evaluates the functionality of these marine reserves based primarily on fish biomass and coral/seagrass/ mangrove cover within their boundaries. It is designed as a quick reference book to a wide range of readers.
Chapter
As a maritime country, the Philippines is a place of high fish consumption. Many coastal villages are populated by fishermen, who are amongst the poorest of working Filipinos. International comparisons show that the Philippine fisheries sector is mostly characterized by small inefficient fishing vessels, while some of the fishing methods are extremely destructive to the resource. Today, fishing moratoriums must be imposed in some areas to allow the reproduction of the fish. Poaching and illegal fisheries, including by foreign vessels, especially from China, plague the most important fisheries areas. Aquaculture has developed to counterbalance the decline of the natural resource, but it has negative ecological effects, among them the disappearance of mangroves. Today, efforts are underway to protect the marine resources of the country, through the implementation of Marine Protected Areas in this biologically rich area of the West Pacific. Part of the “Coral Triangle” initiative, the Republic of the Philippines encourages local efforts to rejuvenate coral reefs and mangroves, while allowing tourism to cohabit with more established uses of the coastal areas of the archipelago.
Article
Studies of marine reserves often describe mean differences in organism size or abundance inside versus outside reserves, but recent work indicates that these differences are influenced by habitat and proximity of sites to reserve borders. In this study, we measured mean effects of reserves and the influence of distance from reserve borders on the number and size of legal (>= 82.5 mm carapace length [CL]) California spiny lobster Panulirus interruptus trapped at sites across a reserve network at the Santa Barbara Channel Islands, California, USA. Additionally, we controlled for habitat variability across sites (1) by measuring relative abundance of sublegal adult lobsters (i.e. those not removed through fishing) and (2) through visual SCUBA surveys on which we quantified fine-scale habitat features. Traps placed in reserves yielded more (4.81 trap(-1)) and larger (7.03 mm CL) legal-sized lobsters than traps placed outside. Multiple linear regression revealed that 2.43 more legal lobsters per trap were captured for every 1 km moved from borders towards reserve centers. Additionally, lobsters tagged and released immediately inside reserve borders were recaptured in areas open to fishing at a higher rate than lobsters tagged and released farther inside reserves. These results suggest that abundance gradients inside reserve borders were caused by net emigration of lobsters (spillover). Sub legal lobsters were more abundant inside reserves and nearer to reserve centers, but these increases were much smaller in magnitude than for legal-sized lobsters. Our results indicate that the differences we observed for legal-sized lobsters were driven primarily by reserve effects but were partially influenced by habitat heterogeneity.
Article
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The utility of no-take marine reserves as fisheries-management tools is con-troversial. It is hypothesized that marine reserves will help to sustain fisheries external to them by becoming net exporters of adults (the ''spillover effect'') and net exporters of propagules (the ''recruitment effect''). Local fishery benefits from spillover will likely generate support from fishing communities for marine reserves. We used underwater visual census to show that biomass of Acanthuridae (surgeonfish) and Carangidae (jacks), two families of reef fish that account for 40–75% of the fishery yield from Apo Island, Phil-ippines, tripled in a well-protected no-take reserve over 18 years (1983–2001). Biomass of these families did not change significantly over the same period at a site open to fishing. The reserve protected 10% of the total reef fishing area at the island. Outside the reserve, biomass of these families increased significantly closer to (200–250 m) than farther away from (250–500 m) the reserve boundary over time. We used published estimates of fishery catch and effort, and fisher interviews (creel surveys) to show that the total catch of Carangidae and Acanthuridae combined at Apo Island was significantly higher after (1985– 2001) than before (1981) reserve establishment. Hook-and-line catch per unit effort (CPUE) at the island was 50% higher during 1998–2001 (reserve protected 16–19 years) than during 1981–1986 (pre-reserve and early phases of reserve protection). Total hook-and-line effort declined by 46% between 1986 and 1998–2001. Hook-and-line CPUE of Acanthuridae was significantly higher close to (within 200 m) than far from the reserve. CPUE of Carangidae was significantly higher away from the reserve, possibly reflecting a local oceanographic effect. The benefits of the reserve to local fisheries at the island were higher catch, increased catch rate, and a reduction in fishing effort. The fishery and tourism benefits generated by the reserve have enhanced the living standard of the fishing community.
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We model marine reserve - fishery linkages to evaluate the potential contribution of habitat-quality improvements inside a marine reserve to fish productivity and fishery catches. Data from Mombasa Marine National Park, Kenya, and the adjacent fishery are used. Marine reserves increase total fish biomass directly by providing refuge from exploitation and indirectly by improving fish habitat in the reserve. As natural mortality of the fish stock decreases in response to habitat enhancement in the reserve, catches increase by up to 2.6 tonnes (t).km(-2).year(-1) and total fish biomass by up to 36 t.km(-2). However, if habitat-quality improvement reduces the propensity of fish to move out of the reserve, catches may fall by up to 0.9 t.km(-2).year(-1). Our results indicate that habitat protection in reserves can underpin fish productivity and, depending on its effects on fish movements, augment catches.
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We examined movement patterns of sportfish that were tagged in the northern Indian River Lagoon, Florida, between 1990 and 1999 to assess the degree of fish exchange between an estuarine no-take zone (NTZ) and surrounding waters. The tagged fish were from seven spe cies: red drum (Sciaenops ocella tus); black drum (Pogonias cromis); sheepshead (Archosargus probatocephalus); common snook (Centropomus undecimalis); spotted seatrout (Cynoscion nebulosus); bull shark (Carcharhinus leucas); and crevalle jack (Caranx hippos). A total of 403 tagged fish were recaptured during the study period, including 65 individuals that emigrated from the NTZ and 16 individuals that immigrated into the NTZ from surrounding waters of the lagoon. Migration distances between the original tagging location and the sites where emigrating fish were recaptured were from 0 to 150 km, and these migration distances appeared to be influenced by the proximity of the NTZ to spawning areas or other habitats that are important to specific life-history stages of individual species. Fish that immigrated into the NTZ moved distances ranging from approximately 10 to 75 km. Recapture rates for sportfish species that migrated across the NTZ boundary suggested that more individuals may move into the protected habitats than move out. These data demonstrated that although this estuarine no-take reserve can protect species from fishing, it may also serve to extract exploitable individuals from surrounding fisheries; therefore, if the no-take reserve does function to replenish surrounding fisheries, then increased egg production and larval export may be more important mechanisms of replenishment than the spillover of excess adults from the reserve into fishable areas.
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There has been increasing interest in recent years in community-based management of natural resources or, where the government is responsible for management, in public participation. Community involvement can range from autonomous management by the community to some form of shared responsibility with state agencies. This trend was in part stimulated by the World Conservation Strategy (UNEP/IUCN/WWF, 1980) which, in promoting the link between conservation and development, represented a major change from the rigid preservationist attitude of many early conservationists (Hanks, 1984). Early protected areas were usually set up by government agencies with the intention of keeping people out. On land this is at least theoretically possible with fences and barriers; it is also possible to move people out of a planned protected area. However, as population pressure and demand for land and resources has increased, this philosophy has become inappropriate and increasingly difficult and expensive to implement (Hough, 1988; McNeeley and Miller, 1984). Hence in many countries there has been growing emphasis on involving local people at some, if not all, levels of protected area establishment and management (IUCN, 1993; Kemf, 1993; Wells et al., 1992).
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The use of no-take marine reserves as fisheries management tools is controversial. A major expectation of marine reserves is that they will become net exporters of adult biomass (the 'spillover effect'), Herein, we show that the biomass of the surgeonfish Naso vlamingii tripled over 18 yr (1983 to 2001) in a reserve at Apo Island, Philippines. Over time, the biomass of N. vlamingii increased by a factor of 40 outside but close to the reserve boundaries (200 to 250 m) but not at greater distances (250 to 500 m). In 2000/2001 hook-and-line catch per unit effort (CPUE) for N. vlamingii was 45 times higher within 200 m of the reserve boundary than for all other fishing grounds combined, with 62.5% of the hook-and-line catch records being recorded within 200 m either side of the reserve, in just 11% of the reef fishing area. This comprises some of the best evidence that reserves can benefit fisheries by spillover.
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A frequent expectation of the use of marine reserves in management of coral reef fisheries is maintenance or enhancement of yields to areas adjacent to reserves by adult (post-settlement) movements from reserve to fished areas (the so-called 'spillover effect'). Demonstration of this effect has been rare. This paper reports on some circumstantial evidence derived from underwater visual census monitoring of densities of large predatory coral reef fish [Serranidae (Epinephelinae), Lutjanidae, Lethrinidae and Carangidae as a group] inside and adjacent to a small marine reserve at Apo Island in the central Philippines over a 10 yr period (1983 to 1993). The marine reserve (sanctuary) at Apo Island was established in 1982 and was protected from fishing for the duration of the study. The non-reserve area was open to fishing by up to 200 municipal fishers using traditional fishing gear (bamboo traps, hooks and lines, gill nets and spears). Significant positive correlations of both mean density and species richness of large predatory fish with duration of reserve protection (from 1 to 11 yr) were observed in both the reserve and non-reserve areas surveyed. The minimum distance from the boundary of the reserve to the non-reserve area surveyed was 200 m. During the first 8 yr of reserve protection combined, the density of large predatory fish at distances 200 to 300, 300 to 400 and 400 to 500 m from the reserve boundary did not differ significantly from an even distribution (chi-squared test, p > 0.05). During the period of 9 to 11 yr of protection combined, there was a significantly higher density of these fish in the area closest to the reserve (i.e. in the 200 to 300 m area, chi-squared test, p < 0.05). This visual census data is consistent with a proposed model of adult fish export from the reserve to the non-reserve areas. Along with interview data collected in 1986 and 1992 that showed that fishers were unanimous that their yields had increased since the reserve was implemented, this study provides evidence for export of adult fish from reserve to fished areas.
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Marine protected areas were established in the Philippines as early as 1974. These early models on Sumilon and Apo Islands and others set forth a framework for coral reef management that has been shown to enhance fish yields to traditional fishers as well as protect and maintain nearshore coral reef habitats for biodiversity and multiple economic uses. The history of marine protected areas in the Philippines is described in relation to their present context. Devolution of authority for management of natural resources to local governments (municipalities and cities) in 1991 is highlighted as a major national policy shift that has supported more localized management efforts. Current policies and laws that influence marine protected areas are explained in relation to field management and results. One community and local government based marine protected area on San Salvador Island is contrasted with a National Marine Park being implemented under the National Integrated Protected Areas System. Important lessons include, among others: the importance of a well-articulated process that includes community participation and ownership in collaboration with municipal governments; the role of multiple stakeholders, government, and donor agencies in planning and management; the creative use of financial mechanisms to create long-term self-supporting marine protected areas; and the need for more integrated forms of coastal management to support marine protected area networks through broad area planning.
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Potential changes in spawning stock biomass per recruit and yield per recruit, when varying fractions of exploitable reef area were closed to fishing, were estimated. Fundamental transfer rates were adjusted for possible density-dependent emigration from closed areas as relative densities decreased in surrounding non-closed areas because of continued fishing. Three hypothetical "fish-types' were constructed, bracketing the likely extremes in fundamental transfer rates and related life-history parameters of Pacific coral reef fishes: a small-bodied, fast-growing and short-lived, strongly philopatric species of damselfish was contrasted with a large-bodied, relatively slow-growing, long-lived, vagile species of jack. A "surgeonfish' type was used to represent intermediate parameter values. -from Author
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The movements, growth rates and distribution of a population of white goatfish Mulloides flavolineatus were investigated using a combination of tag-and-release and sonic tracking techniques. The study site was a 137 km2 patch reef which has been a no-fishing conservation zone for over 30 years. The population showed high site fidelity; 93% of recaptures occurred at the release site, with times at liberty of up to 531 days. Tracking revealed crepuscular movements away from daytime schooling sites to consistent nighttime foraging grounds up to 600 m away. The route taken between daytime and nighttime habitats was the same each night. Suround-net quadrats were used to measure goatfish densities on the nighttime feeding grounds. The high site fidelity and limited range of diel movements of these fish indicate that quite small harvest refugia can serve to effectively protect populations of mature adults, and that for most of the year, emigration of adults into adjacent fisheries was minimal.
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The short-and long-term movement patterns of blue trevally (Caranxmelampygus) were monitored using a combination of sonic tracking and tag-and-release techniques. All fish were captured and released on the patch reef surrounding Coconut Island in Kaneohe Bay, Oahu, Hawaii, which has been a no-fishing conservation zone for over 30 years. Sonic tracking produced fine-scale movement data from five fish for periods spanning up to 18 days. All fish displayed die1 movement patterns within consistent home ranges, which encompassed different parts of the reef during the night than during the clay. Movements were predominantly along the walls of the patch reef, with occasional forays to nearby sections of adjacent reefs. Four hundred and ten fish were tagged and released on the Coconut Island reef, and the recapture sites of 85 recaptured fish indicated that most did not move far from their point of release; 75.5% were recaptured within 0.5 km of their release points. Time at liberty ranged from 4 to 454 days, and distance between release and recapture sites was not related to time at liberty. Some fish were observed many times in the same areas over periods of several months. Both the tracking and recapture data indicate strong site fidelity in this species and low occurrence of long distance emigration. These behavioral traits suggest that successful husbandry of this species may be accomplished through the use of management practices such as establishing no-fishing zones.
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Suitability of small (km2) marine reserves for protecting a commercially important endemic Hawaiian goatfish, Parupeneus porphyreus, was examined by quantifying goatfish habitat use, home range size and site fidelity in an existing marine reserve (Coconut Island in Kaneohe Bay, Hawaii). Five goatfish equipped with acoustic transmitters were tracked for up to 93h each over 3–14 days. Daytime habitat use patterns of two of these fish were continuously monitored for one month using a fixed hydrophone hardwired to an onshore computer. Acoustically tagged fish showed consistent diel patterns of behavior, refuging in holes in the reef by day and moving over extensive areas of sand and coral rubble habitat at night. Remote monitoring of daytime habitat use by two goatfish revealed that the same daytime refuge was used by both fish for at least one month (the battery life of the transmitters). Home ranges of all fish were within the boundaries of the Coconut Island reserve suggesting that even small areas containing suitable habitat can make effective reserves for this species. A relatively low abundance of reproductive size P. porphyreus at Coconut Island in comparison with deeper areas may indicate an ontogenetic shift to deeper habitat in this species.
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Marine reserves are areas of the sea where fishing is not allowed. They provide refuges where populations of exploited species can recover and habitats modified by fishing can regenerate. In some places, closed areas have been used for fisheries management for centuries [1] and, until recently, natural refugia also existed, inaccessible through depth, distance or adverse conditions. Developments in technology have left few areas of fishing interest beyond our reach. Recently, the idea of marine reserves as fisheries management tools has re-emerged with developing interest in ecosystem-based management, and observations of incidental fisheries benefits from reserves established for conservation. In light of new evidence, we argue that, by integrating large-scale networks of marine reserves into fishery management, we could reverse global fishery declines and provide urgently needed protection for marine species and their habitats.
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Structural shelter of the appropriate size has been assumed to be a primary limiting resource for coral-reef fishes. Two corollaries of this limited shelter hypothesis were tested for fishes occupying 12 concrete-block reefs in a seagrass bed off St. Thomas, US Virgin Islands. Corollary I was that, holding reef size and hole size constant, reefs with more holes should support more fishes of that size than reefs with fewer holes. On reefs with 0, 12 and 24 large holes, number of large resident fishes (squirrelfishes, groupers, and moray eels) increased directly with the abundance of holes. Availability of small shelters (gaps between blocks) was approximately constant on the reefs, so small resident fishes did not show the same pattern. Corollary II was that, holding reef size and hole number constant, reefs with small holes should support more small fishes than reefs with large holes, which should support more large fishes. This prediction was also verified. Beyond the effects of shelter variables, there was a statistically significant negative relationship between the number of resident piscivores and maximum number of small fishes on any reef. This pattern suggested that piscivores set the upper limit to the number of small fishes on a reef. An indirect interaction apparently exists between large shelters and small reef fishes: an increase in the abundance of large shelters causes an increase in the abundance of large piscivorous fishes, which in turn causes a decrease in the local abundance of small prey fishes. Artificial reefs designed for persistent fisheries should include both small holes for small fishes (as refuges from predation) as well as large holes for predatory "target' species (as home sites). -from Authors
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The question of how far the larvae of marine organisms disperse is fundamental to an understanding of their population dynamics1, 2, 3, the management of exploited species4, 5 and the conservation of marine biodiversity6, 7. It is generally assumed that larvae disperse away from their natal population so that local populations operate as 'open' systems, driven by recruitment of larvae from other sub-populations8. However, this assumption has never been critically tested. Here we show for the first time that juveniles from a coral reef fish population can return to their natal reef. We marked otoliths (ear bones) of over 10 million developing embryos of the damselfish, Pomacentrus amboinensis, at Lizard Island (Great Barrier Reef). Subsequently, from an examination of 5,000 juveniles settling at the same location, we found 15 marked individuals. On the basis of an estimate of the proportion of embryos marked (0.5–2%), as many as 15–60% of juveniles may be returning to their natal population (self-recruitment). We challenge the assumption that long-distance dispersal is the norm for reef fish populations.
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Marine reserves have been widely promoted as conservation and fishery management tools. There are robust demonstrations of conservation benefits, but fishery benefits remain controversial. We show that marine reserves in Florida (United States) and St. Lucia have enhanced adjacent fisheries. Within 5 years of creation, a network of five small reserves in St. Lucia increased adjacent catches of artisanal fishers by between 46 and 90%, depending on the type of gear the fishers used. In Florida, reserve zones in the Merritt Island National Wildlife Refuge have supplied increasing numbers of world record–sized fish to adjacent recreational fisheries since the 1970s. Our study confirms theoretical predictions that marine reserves can play a key role in supporting fisheries.
Article
Spillover, the net export of adult fish, is one mechanism by which no-take marine reserves may eventually have a positive influence on adjacent fisheries. Although evidence for spillover has increased recently, mechanisms inducing movement of adult fish from reserve to fished areas are poorly understood. While density-dependent export is a reasonable expectation, given that density of fish targeted by fisheries should increase over time inside well-protected no-take reserves, no study to date has demonstrated development of the process. This study provides evidence consistent with density-dependent export of a planktivorous reef fish, Naso vlamingii, from a small no-take reserve (protected for 20 years) at Apo Island, Philippines. Mean density of N. vlamingii increased threefold inside the reserve between 1983 and 2003. Density approached an asymptote inside the reserve after 15-20 years of protection. Modal size in the reserve increased from 35 to 45 cm total length (TL) over 20 years of protection. In addition, both density and modal size increased outside the reserve close to (200-300 m), but not farther from (300-500 m), the reserve boundary over the 20 years of reserve protection. Movement of adult N. vlamingii across the boundaries of the reserve was rare. Aggressive interactions among adult N. vlamingii were significantly higher (by 3.7 times) inside than outside the reserve. This suggests that density-dependent interactions were more intense inside the reserve. When interacting adults differed in size, the larger individual usually chased away the smaller one. Furthermore, the mean size of adult fish captured by experimental fishing decreased from 35-cm TL 50-100 m outside the boundary, to 32-cm TL 250-300 m outside the boundary. This represents some of the best evidence available for density-dependent home-range relocation of fish from a no-take reserve.
Article
The short- and long-term movement patterns of blue trevally (Caranxmelampygus) were monitored using a combination of sonic tracking and tag-and-release techniques. All fish were captured and released on the patch reef surrounding Coconut Island in Kaneohe Bay, Oahu, Hawaii, which has been a no-fishing conservation zone for over 30 years. Sonic tracking produced fine-scale movement data from five fish for periods spanning up to 18 days. All fish displayed diel movement patterns within consistent home ranges, which encompassed different parts of the reef during the night than during the clay. Movements were predominantly along the walls of the patch reef, with occasional forays to nearby sections of adjacent reefs. Four hundred and ten fish were tagged and released on the Coconut Island reef, and the recapture sites of 85 recaptured fish indicated that most did not move far from their point of release; 75.5% were recaptured within 0.5 km of their release points. Time at liberty ranged from 4 to 454 days, and distance between release and recapture sites was not related to time at liberty. Some fish were observed many times in the same areas over periods of several months. Both the tracking and recapture data indicate strong site fidelity in this species and low occurrence of long distance emigration. These behavioral traits suggest that successful husbandry of this species may be accomplished through the use of management practices such as establishing no-fishing zones.
Article
The dispersal of the surf-zone teleost galjoen from the De Hoop Marine Reserve, South Africa, was investigated. Most recoveries were at the site of release; the remainder covered a distance of up to 1040 km. There was no difference with respect to age, sex, or season between those that dispersed and those that did not. The tagged population was probably polymorphic, with fish displaying either resident or nomadic behaviour. The estimate of emigration from the reserve implies that the unharvested reserve population is restocking adjacent exploited areas with adult fish. -from Authors
Article
Movements of Plectropomus leopardus (Serranidae), a major fisheries species, across marine reserve boundaries were investigated on the Great Barrier Reef, Australia. Mark-release-recapture and ultrasonic telemetry were used to assess movements. Mark-release-recapture used hook and line as the method of capture and underwater visual census (UVC) as the "recapture" tool. Catch rates were significantly higher in zones closed to fishing, despite UVC indicating no significant differences in density between closed and open zones. Of 183 fish marked with numerical freeze brands, 93 estimates of movements of branded fish were obtained. No branded fish was recorded to cross the reserve boundaries during the 2-month study, probably due to the initial decision to allocate capture effort evenly across the study area, rather than concentrating it on reserve boundaries. Fish carrying ultrasonic transmitters, and having tome ranges straddling reserve boundaries, crossed boundaries on average 15.3 times.month(-1). The mean distance moved by freeze branded specimens between capture and recapture was significantly larger in areas closed to fishing than in those open to fishing. However, mean distance moved per day determined by ultrasonic telemetry did not differ between areas closed and open to fishing. This study suggests low flux rates of adult P. leopardus across marine reserve boundaries.
Article
This chapter reviews the utility of marine reserves as a management tool for reef fisheries management. The term “marine reserves” is defined as “no-fishing” areas in the marine environment, that is, areas permanently closed to fishing. The lack of solid empirical knowledge about what marine reserves can achieve as fisheries management tools has sometimes been cited by fisheries managers as a reason for not using such approaches for fisheries management. Conventional fisheries management techniques have, by themselves, generally failed to control fishing effort, and have often failed to prevent recruitment overfishing. Techniques such as effort and catch controls are also often difficult to administer in the coral reef fisheries of many developing nations. Thus, marine reserves may be one of the few viable fisheries management options available to the reef fisheries of developing nations. Unlike conventional effort/catch controls, they appear to have a chance of being accepted by subsistence and artisanal fishing communities, often because they offer a variety of other benefits to the community, such as income from tourism. Marine reserves simplify management of multispecies fisheries and they can provide a refuge for species with life histories that make them more susceptible to intense, relatively nonselective fishing. Marine reserves as fisheries management tools should be viewed as a healthy dose of the precautionary principle. Moreover, they can act as an insurance policy against future fisheries management failures and overfishing.
Article
The application of no-take marine-reserve status to an area is expected to increase spawning-stock biomass of species targeted by fisheries, and to help sustain fish- eries external to the reserve. However, empirical evidence on rates and patterns of increase of density and biomass of target species following closures to fishing, and of decrease when reserve status is removed, remains rare. We have monitored density and biomass of large predatory coral-reef fish (Serranidae (Epinephelinae), Lutjanidae, Lethrinidae, and Car- angidae, as a group) visually in two small no-take marine reserves and at two control (open to fishing) sites in the Philippines from 1983 to 2000. At Sumilon reserve a complex history of management allowed 13 measurements of density and biomass at durations of reserve protection of 23 yr (i.e., fished for 3 years after reserve status removed) to 9 yr. At Apo reserve 13 measurements were taken at durations of protection of 1-18 yr. We recorded 11 significant (P , 0.05) changes in density at the four sites over the 17 years, three declines and eight increases. All three significant declines occurred when reserve protection was removed. Four of the eight significant increases occurred when reserve status was applied. This represents some of the best evidence currently available that application of marine-reserve status causes increases in abundance of target species. Three of the four significant increases in density required 4-6 yr of protection. Significant positive linear correlations of mean density of large predators against years of reserve protection were observed at both reserves. The pattern of increase of mean biomass against years of reserve protection was exponential, with biomass initially increasing more slowly than density. Density and biomass increased by factors of 12.2 and 17.3, respectively, during 18 yr of continuous protection in Apo reserve. At Sumilon Island three bouts of unregulated fishing of 1.5-3 yr duration eliminated density and biomass gains accumulated over 5-9 yr of marine reserve protection.
Article
Reductions in fishing mortality within no-take coral reef marine reserves can produce gradients in the density and size of fishes across reserve boundaries. Such gradients may be affected by other factors, however, including differences in habitat quality between reserve and non-reserve areas and the movement of fish across reserve boundaries. To examine the effects of protection from fishing mortality and of habitat quality on an assemblage of exploited reef fishes, we measured the spatial patterns of fish density and size on fringing reefs near the boundary of the Barbados Marine Reserve (Barbados, West Indies) and statistically controlled for habitat correlates of fish density and size. Reserve sites supported a higher total density and size of fishes than non-reserve sites. Most species had a non-significantly higher mean density and size at reserve sites. The density and/or size of many species were correlated with the depth, rugosity, and/or substrate composition of sites. After statistically controlling for the effects of habitat correlates, the difference in total density between reserve and non-reserve sites remained significant, and the mean density and size of most species remained nonsignificantly higher at reserve sites. Neither the mobility of species nor their vulnerability to capture by Antillean fish traps was correlated with their relative difference in density or size between reserve and non-reserve sites. Spearfishing target species had a significantly higher relative difference in size between reserve and non-reserve sites than non-target species. Protection from fishing mortality and higher habitat quality appear to contribute to the increased density and size of fishes on study reefs in the Barbados Marine Reserve, and this difference is not compromised by emigration from the reserve.
Article
High population densities of larger fish within reserves could result in emigration of fish to surrounding non-reserve areas, producing a gradient of abundance and mean size across the reserve boundaries. The difference in fish abundance and size between reserve and non-reserve should be higher for sedentary than for mobile species and for highly catchable than for less catchable species. To test these hypotheses we estimated the abundance and size of fishes by trapping and visual census on fringing reefs in Barbados: 5 reefs within the 2.2 km of the Barbados Marine Reserve (BMR) and 8 reefs in the non-reserve (NR) area within 4 km of the reserve boundaries. The abundance of large, trappable size fish of all species combined was higher in the BMR than in the NR, but abundance of small, nontrappable fish did not differ between BMR and NR. Trap catches decreased gradually with distance from the BMR center, but this gradient of abundance was less evident in visual census counts of trappable size fishes of all species combined, and not apparent in trap or visual census estimates of abundance for individual species. Mean size was larger in the BMR than in the NR for 18 out of 24 species. The relative differences in both abundance and size between BMR and NR did not differ between mobile and sedentary fish taxa. However, for sedentary taxa, the relative differences in abundance and size increased with trappability (the vulnerability to traps, which are the most common fishing method). These patterns suggest that the BMR does protect the fish community from fishing mortality and that emigration rates are generally low. Trappability and mobility depend on complex behavioral characteristics of fishes and are potentially important for the functioning of marine reserves.
Article
Recruitment rates are determined by larval production, and both intrinsic (eg reproductive mode, larval behavior) and extrinsic (eg predation, resource availability, currents) factors that influence the geographic range over which a refuge can effectively supply recruits. The size, number, and distribution of refuges depend on patterns of larval replenishment. Since resource requirements of fish often change with ontogeny and reproductive condition, refuges may need to include a wide variety of habitats. Larval production by refuges may be enhanced by multispecies management that provides protection for or allows harvesting of nontarget species. Additionally, protection may be needed for resources located outside refuges that enhance recruitment to harvested populations. -from Authors
Article
Marine fisheries refugia, unaltered areas that serve as sources of replenishment, can potentially compensate for recruitment and ecosystem overfishing and enhance fishery yields for some coastal stocks. Evidence from existing marine reserves indicates that increased abundance, individual size, reproductive output, and species diversity occurred in a variety of marine species in refuges of various sizes, shapes, and histories in communities ranging from coral reefs to temperate kelp forests. Fishery yield enhancement in areas surrounding refuges occurred in the few studies where yields were examined. The export of propagules required to enhance fisheries in areas surrounding refugia adds a level of complexity to the design of fishery refugia beyond that of terrestrial reserves. Fishery refugia design should consider species life histories, oceanographic regimes, habitat quality, and socioeconomic factors. -from Authors
Article
The excessive and unsustainable exploitation of our marine resources has led to the promotion of marine reserves as a fisheries management tool. Marine reserves, areas in which fishing is restricted or prohibited, can offer opportunities for the recovery of exploited stock and fishery enhancement. In this paper we examine the contribution of fully protected tropical marine reserves to fishery enhancement by modeling marine reserve-fishery linkages. The consequences of reserve establishment on the long-run equilibrium fish biomass and fishery catch levels are evaluated. In contrast to earlier models this study highlights the roles of both adult (and juvenile) fish migration and larval dispersal between the reserve and fishing grounds by employing a spawner-recruit model. Uniform larval dispersal, uniform larval retention and complete larval retention combined with zero, moderate and high fish migration scenarios are analyzed in turn. The numerical simulations are based on Mombasa Marine National Park, Kenya, a fully protected coral reef marine reserve comprising approximately 30% of former fishing grounds. Simulation results suggest that the establishment of a fully protected marine reserve will always lead to an increase in total fish biomass. If the fishery is moderately to heavily exploited, total fishery catch will be greater with the reserve in all scenarios of fish and larval movement. If the fishery faces low levels of exploitation, catches can be optimized without a reserve but with controlled fishing effort. With high fish migration from the reserve, catches are optimized with the reserve. The optimal area of the marine reserve depends on the exploitation rate in the neighboring fishing grounds. For example, if exploitation is maintained at 40%, the ‘optimal’ reserve size would be 10%. If the rate increases to 50%, then the reserve needs to be 30% of the management area in order to maximize catches. However, even in lower exploitation fisheries (below 40%), a small reserve (up to 20%) provides significantly higher gains in fish biomass than losses in catch. Marine reserves are a valuable fisheries management tool. To achieve maximum fishery benefits they should be complemented by fishing effort controls.
Article
The dispersal of the surf-zone teleost galjoen (Coracinus capensis) from the De Hoop Marine Reserve, South Africa, was investigated. Over a period of 5.5 yr, 11 022 galjoen were tagged in the centre of the reserve. Most of the 1008 recoveries were at the site of release, while the remainder covered a distance of up to 1040 km. There was no difference with respect to age, sex, or season between those that dispersed and those that did not. Six models were developed to test the hypotheses that (1) galjoen are polymorphic with respect to dispersal behaviour, (2) nonreporting of tags masks a random dispersal process, and (3) the recovery distribution is the result of unequal movement rates in different areas. It is inferred from the likelihoods of the various models that the tagged population was polymorphic, with fish displaying either resident or nomadic behaviour. This conclusion is unaffected by a large uncertainty in the extent of nonreporting of recoveries, or by spatial variability of movement rates. The estimate of emigration from the reserve implies that the unharvested reserve population is restocking adjacent exploited areas with adult fish.
Article
Marine sanctuaries are increasingly being promoted as tools for conservation and fisheries management. This study investigates the effects of protection over 19 years on substrate composition and fish communities in four marine sanctuaries and corresponding non-sanctuary areas in the Philippines and examines the importance of community support, management measures and enforcement of regulations on these ecological effects. Between 1981 and 2000, substrate cover variables were measured using line transects with scuba and snorkel surveys, and fish censuses (identification to family level) were conducted using scuba within a 500 m2 area. Semi-structured interviews collected data on community support for the sanctuaries, and observations and interviews established management and enforcement aspects of the sanctuaries. Over time, all sanctuaries showed improvements, or maintenance of, ecological variables compared with pre-enforcement times, with maintenance of hard coral cover and average increases of 8.3% in fish species richness and 54.9% in fish abundance. In comparison, non-sanctuary areas showed maintenance of the status quo or declines in ecological variables. However hard coral cover, fish abundances and fish species richness showed significant declines as well as increases in sanctuary areas. Community, management and enforcement factors were significantly related to positive ecological trends in sanctuary areas; management and enforcement were related to a wider variety of ecological factors than community score. Community support was significantly related to an increase in hard coral cover in deep areas. Enforcement of regulations was significantly related to an increase in abundance of fishery target fish species in sanctuary areas, and simple management measures were significantly related to an increase in abundance of large predators. Supportive communities that voluntarily implemented sanctuary regulations, improved enforcement, and small discrete cohesive communities may have facilitated the process of building this community support. Well-enforced sanctuaries that showed an increase in abundance of target species may have contributed to the maintenance of fish yields in adjacent non-sanctuary areas. The effects of sanctuary implementation varied on a case-by-case basis, influenced by environmental, biological, physical and human factors. However, a combination of community support, management measures and enforcement of regulations contributed towards positive ecological trends in sanctuary areas.