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Economic valuation of the snapper recruitment effect from a well-established temperate no-take marine reserve on adjacent fisheries
Abstract
The global exhaustion of marine fishery resources has triggered worldwide demands for sustainable utilization of marine resources and Ecosystem-Based Management (EBM). Marine Protected Areas (MPAs) are a long-term spatial management strategy in the EBM toolbox. MPAs demonstrate ecological and economic benefits. While MPAs’ ecological benefits are well researched, there are only a few studies that estimate the economic benefits of MPAs to the adjacent fisheries. Currently, methodologies for measuring the economic benefits flowing from MPAs are underdeveloped. Our research builds on a recent assessment of the economic contribution of a small, temperate, no-take marine reserve in New Zealand to rejuvenating depleted snapper (Sparidae: Chrysophrys auratus) stocks. Empirical evidence shows that 10.6% of newly settled juvenile snappers sampled up to 55 km outside of the MPA were the offspring of adult snappers from the MPA. This suggests a significant boost to the commercial fishery of $NZ 1.49 million catch landing value per annum and $NZ 3.21 million added from recreational fishing activity associated spending per annum. These values all come from the recruitment effects associated with one species, from only 0.08% of the marine space in the Hauraki Gulf, New Zealand. The economic valuation of this marine reserve’s snapper recruitment effect demonstrated $NZ 9.64 million in total spending accruing to recreational fishing per annum and $NZ 4.89 million in total output to commercial fisheries annually. This study is the first estimation of the economic valuation of the recruitment effects from a well-established temperate no-take MPA. It represents an important step forward for quantifying the economic benefits of marine reserves and how marine reserves could have positive influence on EBM and marine sustainability.
... Fisheries managers must consider economic trade-offs created by spatial or aspatial fisheries decisions (Qu et al., 2021;Sen, 2010;Sumaila, 2021). Western approaches to understanding these tradeoffs typically involve cost-benefit analyses, which have often espoused shorter term perspectives and treated marine organisms as commodities while ignoring broader ecosystem perspectives (Sumaila, 2021). ...
... In both cases, the short-term costs to commercial fishers might be immediate catch reductions (i.e. if abundance already is near the USR or exploitation near F MSY ; or if shifting reference points places stocks in the critical zone, triggering a rebuilding plan). The long-term benefits to fishers, however, include catch increases due to spillover from MPAs (Barceló et al., 2021;Qu et al., 2021) and improved catch stability under climate change if exploitation limits are set to maintain ecosystem functions (Holsman et al., 2020). ...
Fisheries science uses quantitative methods to inform management decisions that reflect cultural preferences which, in turn, indirectly influence the states of ecosystems. To date, it has largely supported Eurocentric preferences for the commodification of marine organisms under the tenets of maximum sustainable yield, whereby abundances are intentionally maintained far below their historical baselines despite broader socio‐ecological trade‐offs. In contrast, Indigenous Knowledge Systems (IKS) adhere to the principle of “take only what you need and leave lots for the ecosystem,” implementing lower fishery removals to support socio‐ecological resilience. Despite the power imbalance favouring Eurocentric preferences in decision‐making, fisheries scientists increasingly recognize that the pairing of IKS and Western science, or Two‐Eyed Seeing, would lead to more holistic management goals. For recognition to transcend tokenism, meaningful collaborations and co‐governance structures underlying knowledge co‐production must carry through to legislated policy changes. Using recent co‐governance developments for fisheries management and spatial protections involving federal, provincial and Indigenous governments in Pacific Canada, we illustrate how the precautionary approach, including reference points and harvest control rules broadly applied in international fisheries, could be revised to make collaborative fisheries management compatible with IKS and improve biodiversity and fisheries protections. Our recommendations may create socio‐economic trade‐offs at different timescales for commercial fishers. Pre‐empting that challenge, we discuss IKS‐compatible economic approaches for addressing shorter term costs arising from reduced exploitation rates. Although our case study derives from Pacific Canada, the insights provided here are broadly applicable elsewhere in the world.
... Evidence that marine protected areas (MPAs) rebuild exploited populations and benefit fisheries already is clear for the temperate coasts of countries that established and began monitoring MPAs decades ago (e.g. New Zealand, Qu et al., 2021;Willis et al., 2003;South Africa, Kerwath et al., 2013;USA-California, Caselle et al., 2015;Lenihan et al., 2021;USA-New England, Murawski et al., 2005; Australia's temperate region, Bosch et al., 2022). Canada, however, has lagged in the establishment, biological monitoring and compliance enforcement of MPAs (Jamieson & Levings, 2001), and-with few exceptions (e.g. ...
... The time required to fill-in depends on the life history of the species-longer lived species, which grow more slowly and mature at older ages, take longer to fill-in than shorter lived species-and on aspects of how the fishery is managed, including age at first capture (Barceló et al., 2021). from additional economic activity generated by recreational fishers (Qu et al., 2021). ...
We, the Haíłzaqv, Kitasoo Xai'xais, Nuxalk and Wuikinuxv First Nations, are the traditional stewards of our territories in the Central Coast of British Columbia, Canada. Our traditional laws obligate us to manage and protect our territories for current and future generations. Spatial management is inherent to our cultures through the Hereditary Chief governance system, in which specific people within a lineage inherit the rights and responsibilities for stewarding specific areas.
Since the 19th century, we have been experiencing cultural disruptions caused by settler colonialism, which are now worsened by the declines of marine species vital to our cultures. These declines reflect fishery impacts exacerbated by climate change.
Western fisheries management focuses on maximum sustained yields (MSY), ignoring body size declines that disrupt food webs and diminish population productivity for vertebrate and invertebrate taxa, thereby eroding resilience to climate change. The worldview encompassed by the MSY framework—take the most that you can without compromising future exploitation while assuming no environmental change—is the antithesis of ours—take only what you need and leave lots for the ecosystem. Furthermore, standard stock assessments do not account for uncertainties inherent to climate change effects on distributions and productivity, and many by‐catch species are unassessed.
Consistent with our traditional knowledge, scientific evidence indicates that marine protected areas (MPAs), coupled with other measures to reduce fishing mortality, can restore exploited species, safeguard biodiversity and contribute to fisheries sustainability.
In the 2000s, we paired Indigenous knowledge and Western science to develop marine spatial plans. These plans are foundational in our contribution to the ongoing development of the Marine Protected Area Network for Canada's Northern Shelf Bioregion (MPAN‐NSB), for which we are co‐governance partners with 14 other First Nations and the governments of Canada and British Columbia.
Our proposed spatial protections for the MPAN‐NSB encompass areas important to many exploited taxa and to corals, sponges, eelgrass beds and other carbon stores. Their implementation would fill conservation gaps which have persisted under current fishery management.
Given our history of spatial management through the Hereditary Chief governance system, the MPAN‐NSB is a culturally appropriate way forward for marine conservation in our territories.
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... Our research used the port price of exploited species to determine their value ($NZ per kg) but we acknowledge that fishing results in multiple economic and social benefits not considered here. Additionally, the economic value of biodiversity is becoming increasingly recognised (Bennett et al., 2015;O'Mahoney et al., 2017;Qu et al., 2021). Further spatial modelling incorporating additional fishing related economic benefits, as well as the economic benefits of carbon sequestration, fisheries recruitment, oxygen production and other biodiversity associated ecosystem services could also enhance our results. ...
Aotearoa (New Zealand) is a global hotspot of marine biodiversity and has a productive commercial fishing industry. Despite the importance of sustainably managing biodiversity to support fisheries, less than 1% of Aotearoa's Exclusive Economic Zone (EEZ) is protected in marine reserves, and Benthic Protection Areas, which cover 28% of the EEZ, are inefficiently placed, providing limited biodiversity and fisheries benefits. Here, we provide a spatial analysis of the Aotearoa EEZ, determining optimal areas that balance marine conservation with the minimal displacement of fishing. We define the minimum length of a big old fat fecund female fish (BOFFFF) for three commercially important exploited species, and use boosted regression trees to determine areas of high reproductive potential. Model results were then used to incorporate reproductive potential into systematic conservation planning. We used the decision-support software Zonation to consider the distribution of threatened species hotspots, biodiversity, and BOFFFFs against fishing catch (all commercially exploited species) and high-value fisheries (10 commercially exploited species) to determine priority areas for marine protection. Results showed that threatened species, biodiversity, and areas with high reproductive potential could be conserved with little impact on fishing catch (86% maintained) and value (87% maintained), though high-value fisheries were found to have greater overlap with biodiversity. Our research indicates that trade-offs with fisheries need not impede the designation of protected areas required to achieve conservation and fisheries sustainability goals.
... Even where good data exist, e.g. in California there is good evidence of local spillover of lobsters [26] but not for changes to wider fish populations [28]. In contrast, studies in New Zealand found that marine reserves made major contributions to wider snapper populations [29]. While MPAs have important roles, they clearly do not replace the need for controls over the types and intensities of human activities in the wider sea. ...
... The final and best estimates are shown in bold such as reaching sexual maturity and the urge to spawn. Nevertheless, the export of these fish from the no-take area of the PMPA (which was considerably greater than from the adjacent exploited area) suggests that this area is actively contributing to both the recreational and commercial linefishery in KZN and provides a clear example of how no-take protected areas can help to sustain fisheries (Edgar et al. 2014;Qu et al. 2021). Garratt et al. (1994) and Mann et al. (2005) both found little evidence of reproductive activity in P. praeorbitalis adults sampled in southern KZN, suggesting that most spawning takes place along the coasts of northern KZN and southern Mozambique (Mann and Garratt 2013). ...
A tag-recapture study was undertaken on Polysteganus praeorbitalis in the Pondoland Marine Protected Area (PMPA) on the east coast of South Africa. A total of 1 042 fish were tagged over a period of 16 years and 255 individuals (24.5%) were recaptured, some of them on multiple occasions. Data analysis showed that 84.7% of recaptured fish remained in relatively small home ranges (-750 m linear distance), while 13.3% abandoned their home ranges and undertook unidirectional movements (of 21-1 211 km) along the KwaZulu-Natal coast in a north-easterly direction, most likely to spawn. While the no-take area of the PMPA provides effective protection for resident fish, the export of adult P. praearbitalis provides strong evidence of the benefits that no-take MPAs can offer to adjacent fisheries. Based on the tag-recapture length data, the growth rate was found to be relatively slow, averaging 46 mm y⁻¹. This growth rate was similar to that determined by a study of ageing using sectioned otoliths. Reliable tag-recapture data can thus be used to provide a valuable means of validating growth rates determined by other methods.
... Furthermore, the creation of the reserve at Apo led to maintained or enhanced total catch for the local fisheries, and in some cases higher catch rates despite reduced fishing effort (Russ et al. 2004, Russ et al. 2015. Similarly, in New Zealand, the snapper recruitment effect from a well-established temperate no-take marine reserve has been estimated to provide economic benefit to adjacent fisheries which is another example of how direct benefits can extend past the reserve boundaries (Qu et al. 2021). ...
The Long Bay-Okura Marine Reserve (established 1995) is a 980-hectare no-take reserve located on the North Shore of Auckland. This reserve is influenced by the urban sprawl of New Zealand’s largest city through high sediment loads from coastal erosion and development. It was established to “protect a typical slice of Hauraki Gulf”, but despite its long protection, few investigations have explored the ecological benefits of this urban marine reserve and how effective it is at protecting species within its boundaries. This thesis examined the diversity of habitats in the reserve as well as the effect of 25 years of protection on two taonga species. To understand the current conditions of the benthic habitats and create a reference point for future comparisons, subtidal habitats were mapped inside and adjacent to the reserve using satellite and aerial imagery with geo-referenced drop camera images of the seafloor to validate habitat categories. Subtidal reef made up 7% of the reserve and was largely covered by canopy-forming large brown algae (Ecklonia radiata, Carpophyllum spp., Sargassum spp.), whereas low relief reef was dominated by turfing algae (e.g. Corallina officinalis) and high sand cover. Habitat composition was comparable inside and adjacent to the reserve. Baited video surveys of reef fishes were used to evaluate reserve protection of carnivorous fishes. As seen in other reserves in northern New Zealand, snapper (Chrysophrys auratus) were substantially larger and more abundant inside, with no legal sized individuals recorded in adjacent fished sites. Sea urchin (kina, Evechinus chloroticus) density and size were evaluated to assess the potential for reserve effects, either increase (protection of fished species) or decrease (via trophic cascades). Kina were generally larger and found at higher densities within the reserve, suggesting benefits from protection in this area and harvesting may have reduced densities on surrounding reefs. This contrasts patterns seen in other reserves in the Hauraki Gulf. Despite the degree of anthropogenic influence, Long Bay-Okura Marine Reserve protects several commercially, culturally, and recreationally important species. This demonstrates that reserves in urbanized areas can have significant ecological effects despite degraded habitat due to sedimentation and stressors associated with urban areas.
Green innovation is of great significance to promote the transformation and upgrading of China's traditional marine fishery. Based on the panel data of Chinese 11 coastal provinces and cities during 2009–2019, the green innovation ability of marine fishery (MFGIA) was measured with entropy method from three dimensions of innovation input, innovation output and innovation potential in this paper. On this basis, the spatial and temporal characteristics were analyzed with spatial autocorrelation method, and the influencing factors and spatial spillover effect of the MFGIA in China were analyzed with spatial econometric model. It is found that, the overall level of the MFGIA was low though it was on the rise during the study period in China; And there were regional differences of the MFGIA in China, mainly showing a spatial positive correlation of high-high agglomeration and low-low agglomeration, presenting a structural characteristic of “High in the center-low on the sides” in regions with high innovation ability and low innovation ability; As to the direct effect of influencing factors, environmental regulation, innovation human resources input, capital input and industrial structure upgrading had a direct promoting effect on the MFGIA in local region, and the level of opening-up had a direct inhibitory effect on the MFGIA in local region; As to the spatial spillover effect, environmental regulation, innovative human resources input, capital input and industrial structure upgrading had positive spatial spillover effect, and the level of opening-up had negative spatial spillover effect. Therefore, a comprehensive spatial planning should be formulated to promote the sustainable development of the MFGIA on the basis of the regional correlation characteristics of the MFGIA in China.
Snapper (Chrysophrys auratus) is an important coastal fish species in New Zealand for a variety of reasons, but the large amount of research conducted on snapper has not been reviewed. Here, we review life history information and potential threats for snapper in New Zealand. We present information on snapper life history, defining stages (eggs and larvae, juvenile and adult), and assess potential threats and knowledge gaps. Overall we identify six key points: 1. post-settlement snapper are highly associated with certain estuarine habitats that are under threat from land-based stressors. This may serve as a bottleneck for snapper populations; 2. the largest knowledge gaps relate to the eggs and larvae. Additional knowledge may help to anticipate the effects of climate change, which will likely have the greatest influence on these early life stages; 3. ocean acidification, from land-based sources and from climate change, may be an important threat to larval snapper; 4. a greater understanding of population connectivity would improve certainty around the sustainability of fishery exploitation; 5. the collateral effects of fishing are likely to be relevant to fishery productivity, ecosystem integrity and enduser value; 6. our understanding of the interrelationships between snapper and other ecosystem components is still deficient.
Marine Protected Areas (MPAs) are increasingly employed as a tool to protect Europe’s swiftly declining marine biodiversity. However, despite increasing coverage, MPA effectiveness and equity is considered highly variable. Concurrently, Ecosystem-Based Management (EBM)—that is, management that aims to protect, restore, or enhance the resilience and sustainability of an ecosystem to ensure sustainable flows of ecosystem services and conserve its biodiversity—is growing in prominence. We applied EBM in the Faial-Pico Channel, a 240 km² MPA in the Azores, Portugal, to assess whether EBM can protect biodiversity whilst meeting diverse stakeholder and policy goals. Collaborating with local stakeholders and policy-makers, this chapter documents the steps of EBM: identifying integrative policy and stakeholder objectives, understanding the social-ecological system, scenario development, and identification and evaluation of EBM measures and policies. We find that stakeholder co-creation and collaboration is a key strength of EBM and should be strengthened in the Faial-Pico Channel. We find that local stakeholders support effective and equitable EBM of MPAs by clearly identifying challenges and priorities, co-creating solutions, providing low-cost knowledge and expertise, and through ongoing monitoring, enforcement, and evaluation of the impact of management.
Open-access fisheries management is susceptible to overexploitation. Therefore, Marine Protected Areas (MPAs) have been increasingly seen as one of the most important tools for sustainable fisheries management. However, MPA still has a possibility to be overfished as MPA may attract fishermen to utilize the area excessively. This study focus on nine MPAs in Indonesia using secondary data collected from Ministry of Marine Affairs and Fisheries and Indonesia Statistic Center Agency from various years. This study used Schaefer and Fox model to measure the Maximum Sustainable Yield (MSY) as the basis to calculate overfishing index. Overfishing comparison analysis is done by mean difference t-test and panel data regression. The result revealed that MPA has lower fishing index compared to non-MPA. Also MPA establishment has negative and significant impact to overfishing index.
Instructions and considerations for ecosystem based management in a useful guide.
The objectives of this study were: 1) to estimate the value of willingness to pay of visitors to participate in consenting the coral reefs and ecosystem of Karimunjawa National Park; 2) to design the contribution fee from visitors to conserve the marine protected area (MPA). The primary data were obtained from the visitors of National Park from 100 respondents using accidental sampling technique. Then, the key persons of Academician, Business, Government, Community (A-B-G-C) were interviewed. The result indicated that respondents' willingness to pay (WTP) to converse the MPA was Rp 18,000, and the estimated hypothetical market to conserve the coral reef and MPA of Karimunjawa was Rp 2.129 million per year. Furthermore, the amount of the retribution fee which should be paid by visitors was designed with collaboration of A-B-G-C.
The utility of marine protected areas (MPAs) as a means of protecting exploited species and conserving biodiversity within MPA boundaries is supported by strong empirical evidence. However, the potential contribution of MPAs to fished populations beyond their boundaries is still highly controversial; empirical measures are scarce and modelling studies have produced a range of predictions, including both positive and negative effects. Using a combination of genetic parentage and relatedness analysis, we measured larval subsidies to local fisheries replenishment for Australasian snapper (Chrysophrys auratus: Spar-idae) from a small (5.2 km 2), well-established, temperate, coastal MPA in northern New Zealand. Adult snapper within the MPA contributed an estimated 10.6% (95% CI: 5.5-18.1%) of newly settled juveniles to surrounding areas (approx. 400 km 2), with no decreasing trend in contributions up to 40 km away. Biophysical modelling of larval dispersal matched experimental data, showing larvae produced inside the MPA dispersed over a comparable distance. These results demonstrate that temperate MPAs have the potential to provide recruitment subsidies at magnitudes and spatial scales relevant to fisheries management. The validated biophysical model provides a cost-efficient opportunity to generalize these findings to other locations and climate conditions, and potentially informs the design of MPA networks for enhancing fisheries management.
The sustainable management of aquatic ecosystems requires better coordination between policies span-ning freshwater, coastal and marine environments. Ecosystem-based management (EBM) has been promoted as a holistic and integrative approach for the safekeeping and protection of aquatic biodiversity. The paper assesses the degree to which key European environmental policies for the aquatic environment, namely the Birds and Habitats Directives, Water Framework Directive and Marine Strategy Framework Directive, individually support EBM and can work synergistically to implement EBM. This assessment is based on a review of legal texts, EU guidance and implementation documents. The paper concludes that EBM can be made operational by implementing these key environmental directives. Opportunities for improving the integration of EU environmental policies are highlighted.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-017-0928-4) contains supplementary material, which is available to authorized users.
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.
Expectations about ecosystem based management (EBM) differ due to diverging perspectives about what EBM should be and how it should work. While EBM by its nature requires trade-offs to be made between ecological, economic and social sustainability criteria, the diversity of cross-sectoral perspectives, values, stakes, and the specificity of each individual situation determine the outcome of these trade-offs. The authors strive to raise awareness of the importance of interaction between three stakeholder groups (decision makers, scientists, and other actors) and argue that choosing appropriate degrees of interaction between them in a transparent way can make EBM more effective in terms of the three effectiveness criteria salience, legitimacy, and credibility. This article therefore presents an interaction triangle in which three crucial dimensions of stakeholder interactions are discussed: (A) between decision makers and scientists, who engage in framing to foster salience of scientific input to decision making, (B) between decision makers and other actors, to shape participation processes to foster legitimacy of EBM processes, and (C) between scientists and other actors, who collaborate to foster credibility of knowledge production. Due to the complexity of EBM, there is not one optimal interaction approach; rather, finding the optimal degrees of interaction for each dimension depends on the context in which EBM is implemented, i.e. the EBM objectives, the EBM initiator’s willingness for transparency and interaction, and other context-specific factors, such as resources, trust, and state of knowledge.
A high-resolution 3D biophysical model was used to investigate the patterns of larval transport for an important commercial and recreational temperate fish, snapper Pagrus auratus, from a well-established marine reserve (Cape Rodney to Okakari Point marine reserve, CROP), and spawning ground. Our focus was to study the effects of local hydrodynamics, contrasting larval vertical behaviours and changing El Niño-Southern Oscillation (ENSO) cycles (via their effect on wind forcing) on the potential larval supply to adjacent non-protected areas. The model suggests the CROP marine reserve provides significant larval subsidies within a relatively small scale (≤40 km), the details of which depend on larval behaviour and ENSO patterns. Changing ENSO patterns mostly affected the dispersal direction of larvae, while larval behaviour was a strong driver only under La Niña conditions. Modelling suggests that under El Niño conditions, snapper larvae are more likely to settle successfully and hence make a strong contribution to surrounding fished stocks. Understanding the contribution of MPAs to fisheries management will require multiple approaches. Modelling will help identify the strength of contributing physical and biological factors, and in due course enable site- and time-specific examples of larval subsidy to be generalised.
Field data on spiny-lobster abundance, habitat quality, and hydrodynamic
transport patterns for a reserve (ECLSP) and three exploited sites (CI, EI,
LSI) were used to assess reserve success in reducing fishing mortality and
increasing theoretical metapopulation recruitment. Fishing mortality was
estimated empirically by quantification of lobster density at ECLSP and the
three exploited sites before and after the start of the fishing season in two
years. Fishing mortality was estimated to be 47–98% lower at the
reserve. Using a circulation model , we theoretically assessed effectiveness
of ECLSP and nominal reserves at the exploited sites in augmenting recruitment
through redistribution of larvae to all sites. Larvae discharged from ECLSP
and EI recruited throughout Exuma Sound, whereas those from LSI and CI
recruited only to CI and LSI. Hence, only reserves at EI and ECLSP would be
suitable for metapopulation recruitment. In selecting an optimal reserve for
metapopulation recruitment, use of information on habitat quality or adult
density did not yield a higher probability of success than did determining the
reserve location by chance. The only successful strategy was one that used
information on transport processes. Designation of effective marine reserves
therefore requires careful attention to metapopulation dynamics and
recruitment processes.
Snapper (Chrysophrys auratus) is an important coastal fish species in New Zealand for a variety of reasons, but the large amount of research conducted on snapper has not been reviewed. Here, we review life history information and potential threats for snapper in New Zealand. We present information on snapper life history, defining stages (eggs and larvae, juvenile and adult), and assess potential threats and knowledge gaps. Overall we identify six key points: 1. post-settlement snapper are highly associated with certain estuarine habitats that are under threat from land-based stressors. This may serve as a bottleneck for snapper populations; 2. the largest knowledge gaps relate to the eggs and larvae. Additional knowledge may help to anticipate the effects of climate change, which will likely have the greatest influence on these early life stages; 3. ocean acidification, from land-based sources and from climate change, may be an important threat to larval snapper; 4. a greater understanding of population connectivity would improve certainty around the sustainability of fishery exploitation; 5. the collateral effects of fishing are likely to be relevant to fishery productivity, ecosystem integrity and enduser value; 6. our understanding of the interrelationships between snapper and other ecosystem components is still deficient.
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.
Marine reserves are quickly gaining popularity as a management option for marine conservation, fisheries, and other human uses of the oceans. Despite the popularity of marine reserves as a management tool, few reserves appear to have been created or designed with an understanding of how reserves affect biological factors or how reserves can be designed to meet biological goals more effectively (e.g., attaining sustainable fish populations). This shortcoming occurs in part because the many studies that have examined the impacts of reserves on marine organisms remain isolated examples or anecdotes; the results of these many studies have not yet been synthesized. Here, I review the empirical work and discuss the theoretical literature to assess the impacts of marine reserves on several biological measures (density, biomass, size of organisms, and diversity), paying particular attention to the role reserve size has in determining those impacts. The results of 89 separate studies show that, on average, with the exception of invertebrate biomass and size, values for all four biological measures are significantly higher inside reserves compared to outside (or after reserve establishment vs. before) when evaluated for both the overall communities and by each functional group within these communities (carniv- orous fishes, herbivorous fishes, planktivorous fishes/invertebrate eaters, and invertebrates). Surprisingly, results also show that the relative impacts of reserves, such as the proportional differences in density or biomass, are independent of reserve size, suggesting that the effects of marine reserves increase directly rather than proportionally with the size of a reserve. However, equal relative differences in biological measures between small and large reserves nearly always translate into greater absolute differences for larger reserves, and so larger reserves may be necessary to meet the goals set for marine reserves. The quality of the data in the reviewed studies varied greatly. To improve data quality in the future, whenever possible, studies should take measurements before and after the creation of a reserve, replicate sampling, and include a suite of representative species. Despite the variable quality of the data, the results from this review suggest that nearly any marine habitat can benefit from the implementation of a reserve. Success of a marine reserve, however, will always be judged against the expectations for that reserve, and so we must keep in mind the goals of a reserve in its design, management, and evaluation.
Gonads from snapper of age classes 0+ to 10+ years sampled from the north-east coast of New Zealand were examined histologically for evidence of sex inversion. All 0+ fish were undifferentiated, and all 1 + fish were immature females. 2+ to 4+ fish had gonads that were either ovary, ovo-testis or testis. Older fish were either male or female. Snapper reach sexual maturity at ages of 2-5 years, so the developmental pattern is one of juvenile sex inversion by some of the population, and functional gonochorism.
The cessation or reduction of fishing in marine protected areas (MPAs) should promote an increase in abundance and mean size and age of previously exploited populations. Thus density-dependent changes in life-history characteristics should occur when populations are allowed to recover in MPAs. In this review, we synthesize the existing information on resource limitation in marine ecosystems, densitydependent changes in life-history traits of exploited populations and evidence for biomass export from MPAs. Most evidence for compensatory changes in biological variables has been derived from observations on populations depleted by high fishing mortality or on strong year classes, but these changes are more evident in juveniles than in adults and in freshwater rather than in marine systems. It is unclear if adults of exploited marine populations are resource limited. This may suggest that exploited populations are controlled mainly by density-independent processes, which could be a consequence of the depleted state of most exploited populations. MPAs could be a useful tool for testing these hypotheses. If
we assume that resources become limiting inside MPAs, it is plausible that, if suitable habitats exist, mobile species will search for resources outside of the MPAs, leading to export of biomass to areas which are fished. However, it is not possible to establish from the available data whether this export will be a response to resource limitation inside the MPAs, the result of random movements across MPA boundaries or both. We discuss the implications of this process for the use of MPAs as fisheries management tools.
The cessation or reduction of fishing in marine protected areas (MPAs) should promote an increase in abundance and mean size and age of previously exploited populations. Thus density-dependent changes in life-history characteristics should occur when populations are allowed to recover in MPAs. In this review, we synthesize the existing information on resource limitation in marine ecosystems, density-dependent changes in life-history traits of exploited populations and evidence for biomass export from MPAs. Most evidence for compensatory changes in biological variables has been derived from observations on populations depleted by high fishing mortality or on strong year classes, but these changes are more evident in juveniles than in adults and in freshwater rather than in marine systems. It is unclear if adults of exploited marine populations are resource limited. This may suggest that exploited populations are controlled mainly by density-independent processes, which could be a consequence of the depleted state of most exploited populations. MPAs could be a useful tool for testing these hypotheses. If we assume that resources become limiting inside MPAs, it is plausible that, if suitable habitats exist, mobile species will search for resources outside of the MPAs, leading to export of biomass to areas which are fished. However, it is not possible to establish from the available data whether this export will be a response to resource limitation inside the MPAs, the result of random movements across MPA boundaries or both. We discuss the implications of this process for the use of MPAs as fisheries management tools.
The proportion of a fish stock that is killed by fishing activity is often calculated as the catch divided by the estimated stock biomass. However, stock biomass is notoriously difficult to estimate reliably, and moreover, the catch may be uncertain or misreported and does not include losses due to discarding. In all too many fisheries, these difficulties have lead to underestimates of total fishing mortality and the commercial demise of the fishery. No-take marine reserves eliminate fishing mortality from within their boundaries and, for species that exhibit seasonal migratory behaviour, comparison of reserves with fished areas can provide direct estimates of the proportion killed by fishing. For an important exploited species in New Zealand, seasonal changes in density of sub-legal fish at three marine reserves were similar in both reserve and adjacent non-reserve areas. However, this result did not hold for legal-size fish, and the difference in seasonal change between reserved and non-reserved areas was used to obtain direct estimates of the total localized fishing mortality in the non-reserve area over 6-month periods. Estimates of the percentage of legal-size fish killed by fishing ranged from 70 to 96%. These results demonstrate an unanticipated practical benefit from marine reserves that goes beyond their ecological role.
1. The use of marine reserves as tools either for conservation or fisheries management requires rigorous empirical evidence for the recovery of exploited species within them.
2. The relative density and size structure of snapper Pagrus auratus (Sparidae), an intensively exploited reef fish species, were measured, using baited underwater video, inside and outside three northern New Zealand marine reserves (Leigh Marine Reserve, Hahei Marine Reserve and Tawharanui Marine Park) every 6 months from October 1997 to April 1999.
3. Log-linear modelling showed that relative total density and egg production of snapper were higher in all three reserves than in fished areas. Snapper that were larger than the minimum legal size were estimated to be 14 times denser in protected areas than in fished areas, and the relative egg production was estimated to be 18 times higher. In the Leigh reserve, legal-size snapper were larger than legal-size snapper in fished areas.
4. At the Leigh reserve, snapper density consistently peaked at the reserve centre and declined towards either boundary, which suggests that snapper became increasingly vulnerable to fishing towards the reserve boundaries.
5. Inshore snapper density was significantly higher in autumn than in spring, supporting previous suggestions that snapper make regular onshore–offshore seasonal migrations that might be related to spawning. We suggest that the observed recovery of snapper populations within reserves is attributable to immigration of individuals from fished areas that take up residency within reserves, rather than juvenile recruitment.
6. Synthesis and applications. This study demonstrates the effectiveness of marine reserves for protecting an exploited species previously thought to be too mobile to respond to area-based protection. Although it is difficult to envisage significant enhancement of fished areas via adult emigration, it is likely that the reserves contribute significantly to local gamete production. In addition, the protection of fish populations within reserves might slow reductions in genetic diversity caused by size-selective mortality brought about by exploitation.
'No-take' marine reserves provide a valuable tool for managing marine resources as well as for providing relatively undisturbed habitat with which to assess modifications to ecosystems. We studied 2 marine reserves in northeastern New Zealand, the Leigh Marine Reserve (established 1975) and Tawharanui Marine Park (established 1982) in order to assess whether changes in protected predator populations had resulted in other indirect changes to grazers and consequently to algal abundance. Estimates of abundance of the most common demersal predatory fish Pagrus auratus indicated that adults of this species (i.e. large enough to prey upon urchins) were at least 5.75 and 8.70 times more abundant inside reserves than in adjacent unprotected areas. Overall. P. auratus were also much larger inside reserves with mean total lengths of 316 mm compared with 186 mm in fished areas. The spiny lobster Jasus edwardsii displayed similar trends, and was approximately 1.6 to 3.7 times more abundant inside the reserves than outside. Lobsters within the reserves had a mean carapace length of 109.9 mm, compared with 93.5 mm outside the reserves. In one of the reserves, densities of the sea urchin Evechinus chloroticus had declined from 4.9 to 1.4 m(-2) since 1978 in areas formerly dominated by it. Consequently, kelp forests were more extensive in 1998 than they were at the time of reserve creation. Urchin-dominated barrens occupied only 14% of available reef substratum in reserves as opposed to 40% in unprotected areas. These changes in community structure, which have persisted since at least 1994, demonstrate not only higher trophic complexity than anticipated in Australasian ecosystems but also increased primary and secondary productivity in marine reserves as a consequence of protection. Trends inside reserves indicate large-scale reduction of benthic primary production as an indirect result of fishing activity in unprotected areas.
The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for future generations. Because a key goal of ecosystem-based MSP is to maintain the delivery of ecosystem services that humans want and need, it must be based on ecological principles that articulate the scientifically recognized attributes of healthy, functioning ecosystems. These principles should be incorporated into a decision-making framework with clearly defined targets for these ecological attributes. This paper identifies ecological principles for MSP based on a synthesis of previously suggested and/or operationalized principles, along with recommendations generated by a group of twenty ecologists and marine scientists with diverse backgrounds and perspectives on MSP. The proposed four main ecological principles to guide MSP—maintaining or restoring: native species diversity, habitat diversity and heterogeneity, key species, and connectivity—and two additional guidelines, the need to account for context and uncertainty, must be explicitly taken into account in the planning process. When applied in concert with social, economic, and governance principles, these ecological principles can inform the designation and siting of ocean uses and the management of activities in the ocean to maintain or restore healthy ecosystems, allow delivery of marine ecosystem services, and ensure sustainable economic and social benefits.
Economic information is critical for explaining why recreational fishing and marine stewardship is important to all citizens of a nation. Successfully raising public awareness of the importance of healthy and abundant marine fisheries is dependent on having reliable economic insights. These types of data can be used to inform discussions about how to institute better conservation policies, secure new partners and resources for conservation initiatives, and ultimately boost the long-term health and productivity of marine fisheries. Until now, the economic contribution of recreational marine fishing in New Zealand has not been measured, placing recreational fishing interests at a disadvantage compared to the commercial sector that has such information in various forms. This project filled that vacuum. Beginning with the $946 million spent annually by more than 600,000 resident and visiting New Zealand fishers, these dollars circulate through the national economy, supporting 8000 jobs, stimulating $1.7 billion in total economic activity, contributing $638 million in Gross Domestic Product and $342 million in salaries, wages and small business profits while adding nearly $187 million in tax revenues. This study was built using data collection and analytical approaches available for use by other nations to increase public awareness of the critical economic importance of their marine fisheries.
Mandates to execute ecosystem-based management exist but are not implemented sufficiently enough to reap the benefits of a growing blue economy.
Climate change, in combination with population growth, is placing increasing pressure on the world's oceans and their resources. This is threatening sustainability and societal wellbeing. Responding to these complex and synergistic challenges requires holistic management arrangements. To this end, ecosystem-based management (EBM) promises much by recognising the need to manage the ecosystem in its entirety, including the human dimensions. However, operationalisation of EBM in the marine environment has been slow. One reason may be a lack of the inter-disciplinary science required to address complex social-ecological marine systems. In the present paper, we synthesise the collective experience of the authors to explore progress in integrating natural and social sciences in marine EBM research, illustrating actual and potential contributions. We identify informal barriers to and incentives for this type of research. We find that the integration of natural and social science has progressed at most stages of the marine EBM cycle; however, practitioners do not yet have the capacity to address all of the problems that have led to the call for inter-disciplinary research. In addition, we assess how we can support the next generation of researchers to undertake the effective inter-disciplinary research required to assist with operationalising marine EBM, particularly in a changing climate.
Large marine protected areas are increasingly being established to meet global conservation targets and promote sustainable use of resources. Although the factors affecting the performance of small-scale marine protected areas are relatively well studied, there is no such body of knowledge for large marine protected areas. We conducted a global meta-analysis to systematically investigate social, ecological, and governance characteristics of successful large marine protected areas with respect to several social and ecological outcomes. We included all large (>10,000 km²), implemented (>5 years of active management) marine protected areas that had sufficient data for analysis, for a total of twelve cases. We used the Social-Ecological Systems Meta-Analysis Database, and a consistent protocol for using secondary data and key informant interviews, to code proxies for fisheries, ecosystem health, and the wellbeing of user groups (mainly fishers). We tested four sets of hypotheses derived from the literature on small-scale marine protected areas and common-pool resources: (i) the attributes of species and ecosystems to be managed in the marine protected area, (ii) adherence to principles for designing small-scale marine protected areas, (iii) adherence to the design principles for common-pool resource management, and (iv) stakeholder participation. We found varying levels of support for these hypotheses. Improved fisheries were associated with older marine protected areas, and higher levels of enforcement. Declining fisheries were associated with several ecological and economic factors, including low productivity, high mobility, and high market value. High levels of participation were correlated with improvements in wellbeing and ecosystem health trends. Overall, this study constitutes an important first step in identifying factors affecting social wellbeing and ecological performance of large marine protected areas.
The application of ecosystem considerations, and in particular ecosystem report cards, in federal groundfish fisheries management in Alaska can be described as an ecosystem approach to fisheries management (EAFM). Ecosystem information is provided to managers to establish an ecosystem context within which deliberations of fisheries quota occur. Our goal is to make the case for the need for qualitative ecosystem assessments in EAFM, specifically that qualitative synthesis has advantages worthy to keep a permanent place at the fisheries management table. These advantages include flexibility and speed in responding to and synthesizing new information from a variety of sources. First, we use the development of indicator-based ecosystem report cards as an example of adapting ecosystem information to management needs. Second, we review lessons learned and provide suggestions for best practices for applying EAFM to large and diverse fisheries in multiple marine ecosystems. Adapting ecosystem indicator information to better suit the needs of fisheries managers resulted in succinct report cards that summarize ecosystem trends, complementing more detailed ecosystem information to provide context for EAFM. There were several lessons learned in the process of developing the ecosystem report cards. The selection of indicators for each region was influenced by geography, the extent of scientific knowledge/data, and the particular expertise of the selection teams. Optimizing the opportunity to qualitatively incorporate ecosystem information into management decisions requires a good understanding of the management system in question. We found that frequent dialogue with managers and other stakeholders leads to adaptive products. We believe that there will always be a need for qualitative ecosystem assessment because it allows for rapid incorporation of new ideas and data and unexpected events. As we build modelling and predictive capacity, we will still need qualitative synthesis to capture events outside the bounds of current models and to detect impacts of the unexpected.
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.
The European Union is aiming to implement an Ecosystem Approach for the management of all human activities in the marine environment, hereunder the fisheries sector. Since the last reform of the Common Fisheries Policy in 2013, several analyses have highlighted the barriers and challenges to this aim. Despite the claim that much of the framework to support the implementation of an EAFM in Europe is in place, the findings point out to deterrent features within the governance system. Beyond the overall policy framework, this paper explores the implementation of the multiannual multispecies management plans as one of the real moves towards Ecosystem Approach to Fisheries Management. This is carried out on the basis of two case studies that address the design of multiannual multispecies management plans for the Baltic Sea and for the Atlantic Pelagic fisheries. The analyses strengthen with empirical evidences our understanding of the challenges ahead including, among others, an institutional gap between fisheries and environmental policy frameworks resulting in a limited integration of broader environmental concerns in one of the proposed plan and the standoff between decision-makers that delays the adoption and use of proposed management plans and creates frustration for the involved agencies.
Coastal states around the world are currently adopting an integrated and ecosystem-based approach to the management of coastal and ocean areas. The main aim is to promote resource use while protecting the integrity of the marine ecosystems. Focus is therefore on the conflict between economic development and conservation. Less attention is paid to the complex uses of the ocean and the conditions for regulating industrial activities and solving multi-use conflicts. This paper discusses principles for dealing with use conflicts in the context of ecosystem-based management. It argues that resolving use conflicts is not only an important issue in its own right, but can also be important for the marine environment and biodiversity. As an illustration, we look at the relationship between the fishing industry and the offshore oil and gas industry in Norway and Vietnam.
Conservation needs places where nature is left wild; but only a quarter of coastal countries have no-take Marine Reserves. 'Marine Protected Areas' (MPAs) have been used to indicate conservation progress but we found that 94% allow fishing and thus cannot protect all aspects of biodiversity. Biodiversity conservation should focus on Marine Reserves, not MPAs.
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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.
This chapter focuses on the use of reef fish management for either fishery use or as part of reef fish conservation. The science of environmental management that is appropriate to coral reefs and coral reef fishes requires coral reef ecologists and other scientists to direct their efforts to management questions and to articulate their science more effectively. Fishery management aims to preserve economic value of a fishery, usually by implementing a set of regulations that will lead to an economically beneficial, but demographically sustainable, harvest of desired species. The difficulties of employing conventional effort-based fisheries management approaches have encouraged the use of two additional approaches. The first is to enrich habitat structure by means of artificial reefs and fish-attracting devices in locations that are not structurally complex, and to fish the resulting aggregations of fishes. The second approach is to create “no-take” marine protected areas (MPAs), on the understanding that the fishes within these areas populate, either through reproduction or emigration, nearby fished regions, enhancing the fishery yield. Conservation management seeks to regulate human activities to minimize direct and indirect negative impacts on valued sites and/or valued species, with the goal of sustaining existence of specific species or of biodiversity in general. Unlike many marine habitats, coral reefs have a rich local topography, and the fishes that occupy them are closely associated with local sites. This offers managers the opportunity to manage fisheries by regulating entry, not to a fishery for a specified product, but to a specific location. The majority of MPAs established in coral reef waters have enhancement of fish stocks as one of their objectives, and are managed to ban all or specific types of fishing within their borders.
Tourists to San Andres Island (SAI) expressed high willingness to pay (WTP) to conserve its beaches.•Estimated annual consumer surplus was US $997,468, about 40% of the Seaflower marine protected area (SMPA) annual budget.•Study results showed potential for large revenue loss (67%) for the tourism industry if beaches were not maintained.•Over 50% of tourists would not return to SAI with loss of half the beach width; 35% of potential returnees would pay less.•Tourist WTP and potential revenue loss to tourism industry could set up PES schemes to finance SMPA operations.
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.
The ecosystem supporting snapper (Pagrus auratus) larvae was studied during three springsummer (NovemberJanuary 19851988) spawning seasons in Hauraki Gulf, New Zealand. Upwelling-favourable winds caused more incursion of shelf water into the Gulf in 19851986 and 19861987 than in 19871988, but in the first two seasons, the winds were relatively weak. Stronger winds in 19871988 drove greater vertical diffusivity and correlated with greater mixed-layer primary biomass and productivity. Effects of vertical mixing appeared to dominate horizontal incursion of upwelled shelf water in supporting upper water column productivity. The more productive 19871988 season had greater abundances of nauplii, copepodites, adult copepods, cladocerans, chaetognaths, hydromedusae, decapod larvae, and numerous larval fish taxa (including snapper). There was much higher survival of snapper between the late-stage egg and post-first-feeding larval stages in 19871988, which correlated spatially and temporally with high larval prey densities. Neither higher egg production, fewer predators, nor less horizontal advection accounted for these strong larval snapper cohorts. We hypothesize that larval competence improved within the superior larval feeding environment, reducing predatory losses. The ecosystem response to wind mixing may partially explain the correlation of sea temperatures with recruitment, previously observed for the Hauraki Gulf snapper stock.
Feeding was examined in five species of fish associated with snapper Chrysophrys auratus (Forster) trawled from Hauraki Gulf and north‐west Bay of Plenty: trevally Caranx lutescens Richardson, red gurnard Chelidonichthys kumu Lesson and Garnot, horse mackerel Trachurus novaezelandiae Richardson, eagle ray Holorhinus tenuicaudatus (Hector), and john dory Zeus japnnicus Cuvier and Valenciennes. All five species feed on some elements of the bottom fauna; in general, crustaceans were the most important food group.
Fecundity estimates were made for snapper Chrysophrys auratus, a serial spawning fish, for the 1974–75 and 1975–76 spawning seasons. Weighed sub‐samples of ovaries were used, and eggs were counted manually. All eggs >0.1 mm diameter were considered potentially capable of being spawned; estimates of these eggs were made at the beginning and end of spawning, and their difference was considered to be the actual fecundity. A log‐log transformation of egg numbers against length offish gave a linear relationship. Fecundity estimates ranged from 297 000 at 25 cm to 4 528 000 at 50 cm in 1974–75, and from 83 000 at 25 cm to 6 164 000 at 50 cm in 1975–76. Counts of ripe eggs were also made, and batch sizes ranging from 13 000 at 25 cm to 104 000 at 50 cm were predicted. By combining these data with fecundity estimates the number of batches spawned was estimated to be 23–44 in 1974–75, depending on and increasing with length; and 6–59 in 1975–76.
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.
Global decline of marine resources has triggered a worldwide demand for changing the way ocean resources are managed. Ecosystem-based management approaches have emerged using marine protected areas (MPA) as the main tool. Several classifications of marine protected areas benefits have been made, but all have focused only on the benefits to humans, neglecting many important benefits accrued to nature. This paper presents a new comprehensive classification of MPA benefits that will provide scientists and managers with an inclusive framework to accurately identify and account for all possible benefits derived from MPAs. The paper also analyses the methods available for valuing these benefits. A total of 99 benefits were identified within nine main categories: fishery, non-fishery, management, education/research, cultural, process, ecosystem, population and species benefits. These categories are arranged in two main divisions (direct and indirect benefits), which, at the same time, fall within the realms of benefits to humans and to nature.
No-take reserves constitute one tool to improve conservation of marine ecosystems, yet criteria for their placement, size, and arrangement remain uncertain. Representation of biodiversity is necessary in reserve planning, but will ultimately fail for conservation unless factors affecting species’ persistence are also incorporated. This study presents an empirical example of the divergent relationships among multiple metrics used to quantify a site’s conservation value, including those that address representation (habitat type, species richness, species diversity), and others that address ecological processes and viability (density and reproductive capacity of a keystone species, in this case, the black chiton, Katharina tunicata). We characterized 10 rocky intertidal sites across two habitats in Barkley Sound, British Columbia, Canada, according to these site metrics. High-richness and high-production sites for K. tunicata were present in both habitat types, but high richness and high-production sites did not overlap. Across sites, species richness ranged from 29 to 46, and adult K. tunicata varied from 6 to 22 individuals m−2. Adult density was negatively correlated with species richness, a pattern that likely occurs due to post-recruitment growth and survival because no correlation was evident with non-reproductive juveniles. Sites with high adult density also contributed disproportionately greater potential reproductive output (PRO), defined by total gonad mass. PRO varied by a factor of five across sites and was also negatively correlated with species richness. Compromise or relative weighting would be necessary to select valuable sites for conservation because of inherent contradictions among some reserve selection criteria. We suspect that this inconsistency among site metrics will occur more generally in other ecosystems and emphasize the importance of population viability of strongly interacting species.
Ecosystem based management takes into account the interconnectedness and interdependent nature of ecosystem components and emphasizes the importance of ecosystem structures and functions which provide a range of services. The concept has now been adopted by many international agreements and national governments and is in the process of being implemented. This paper seeks to review the literature and to analyze the understanding of the subject. The term is defined and its implementation in fisheries and for all marine uses is analyzed. It has been concluded that to understand marine ecosystem based management one must consider ecosystems as complex adaptive systems which can show changes at higher levels from actions and processes occurring at lower levels. Recognizing that humans are part of these complex adaptive systems is vital in that their actions along with other processes can lead to transformations in ecosystem functioning. This recognition is also important to show how society can sustainably exploit these resources and that the inclusion of all stakeholders in the management process is necessary to legitimize the process. The uses of the precautionary principle along with adaptive management are seen to be useful tools in implementing these insights into the management of natural resources. Finally, the need for reducing consumption of fish is considered.
Overfishing can have detrimental effects on marine biodiversity and the structure of marine ecosystems. No-take marine reserves (NTMRs) are much advocated as a means of protecting biodiversity and ecosystem structure from overharvest. In contrast to terrestrial protected areas, NTMRs are not only expected to conserve or recover biodiversity and ecosystems within their boundaries, but also to enhance biodiversity beyond their boundaries by exporting species richness and more complex biological communities. Here we show that species richness of large predatory reef fish increased fourfold and 11-fold inside two Philippine no-take marine reserves over 14 and 25 years, respectively. Outside one reserve (Apo) the species richness also increased. This increase beyond the Apo reserve boundary was 78% higher closer to the boundary (200-250 m) than farther from it (250-500 m). The increase in richness beyond the boundary could not be explained by improvements over time in habitat or prey availability. Furthermore, community composition of predatory fish outside but close to (200-250 m) the Apo reserve became very similar to that inside the reserve over time, almost converging with it in multivariate space after 26 years of reserve protection. This is consistent with the suggestion that, as community composition inside Apo reserve increased in complexity, this complexity spilled over the boundary into nearby fished areas. Clearly, the spillover of species richness and community complexity is a direct consequence of the spillover of abundance of multiple species. However, this spillover of species richness and community complexity demonstrates an important benefit of biodiversity and ecosystem export from reserves, and it provides hope that reserves can help to reverse the decline of marine ecosystems and biodiversity.
The world's oceans are now attracting the serious attention of conservationists. Paradoxically, as the value of marine biological diversity is recognized, the ecosystems that harbor this diversity are fast becoming degraded. New thinking about how to conserve coastal areas has resulted in protected-area models that incorporate principles of landscape ecology, adaptive and ecosystem management, and zoning in protected-area plans.