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The role of in situ coral nurseries in supporting mobile invertebrate epifauna
Abstract
Coral nurseries are commonly employed to generate coral material for reef restoration projects, but observations of epifaunal organisms utilising the nurseries for food and shelter indicate that they can also provide important functions beyond that of coral propagation. To examine the level of biodiversity that can be supported by coral nurseries, and investigate if epifaunal communities were influenced by the presence of live coral tissue, we compared the abundance, diversity and community composition of mobile invertebrate epifauna associated with live and dead fragments of three coral species (Pocillopora acuta, Echinopora lamellosa, Platygyra sinensis)that were reared in an in situ nursery. A total of 418 mobile invertebrates spanning 63 taxa were recorded from 22 coral colonies. The three coral species hosted significantly different epifaunal communities, most likely a consequence of the difference in growth forms of the coral hosts. Significant differences in epifaunal communities were only observed between live and dead colonies of P. acuta, indicating that resource provisioning in this species is particularly influenced by the presence of live tissue. Our findings showed that coral nurseries can support a range of mobile invertebrates and function as tools to conserve threatened mobile invertebrates. This ecological function is under-studied and should be assessed in restoration programs for the conservation of corals and associated fauna.
... Additionally, in many degraded reef areas, the substrates are no longer suitable for coral attachment due to factors such as dynamite fishing, sedimentation from land reclamation, or phase shift events [30][31][32][33] . Furthermore, the current practice of individual colony-planting overlooks one of the significant advantages of underwater coral nurseries compared to sterile terrestrial nurseries, following which the underwater nurseries have surfaced as platforms for recruiting reef-associated organisms [34][35][36][37] . Since reef-associated fauna is also under significant threat from degradation 2,38 , incorporating these recruited organisms alongside farmed colonies could enhance biodiversity in transplanted reefs. ...
... Unlike previous studies that often regarded dead colonies as losses or failures in restoration efforts 29,73 , this research recognizes the ecological significance and potential contributions of these structures. Live and dead corals offer different resources for reef fauna 37,69,74,75 . For example, live corals provide nutritional sources such as live coral tissue, mucus, and the release of particulate organic matter, whereas micro/filamentous algae and detritus are abundant on dead coral surfaces, which also provide a more generous assortment of food resources. ...
... For example, live corals provide nutritional sources such as live coral tissue, mucus, and the release of particulate organic matter, whereas micro/filamentous algae and detritus are abundant on dead coral surfaces, which also provide a more generous assortment of food resources. The live and dead coral colonies offer different shelter types and camouflage opportunities 69,76 , providing different settlement cues for reefassociated taxa 37,68 , and even different substrates for specialized burrowers and gall-forming species 38 , as for encrusting and sessile invertebrates. The surface covered by coral tissue is homogenous and somewhat simplified compared with the spatial heterogeneity of microhabitats provided by dead corals 44,77 . ...
To enhance the practice of farmed-coral transplantation, we conducted a trial of an approach called “Reef Carpets” (RC), which draws inspiration from the commercial turf-grass sod in land-based lawn gardening. Three 8.4m² RCs were established on a sandy seabed, containing preselected combinations of branching corals (Acropora cf. variabilis, Pocillopora damicornis, Stylophora pistillata) with nursery recruited dwellers, and were monitored for 17-months. Corals within RCs grew, supported coral recruitment and offered ecological habitats for coral-associated organisms. While the unstable sediment underneath the RCs increased corals’ partial mortalities, corals managed to grow and propagate. The extent of fish and gastropods corallivory varied among the coral species and planulation of Stylophora transplants was significantly higher than same-size natal-colonies. The RCs provided conducive environments for fish/invertebrate communities (183 taxa), and each coral species influenced specifically species-diversity and reef-associated communities. Even dead corals played crucial roles as habitats for reef biota, sustaining >80% of the RCs diversity; hence, they should not be considered automatically as indicators of failure. RCs scaled-up reef restoration and generated, in short periods, new reefs in denuded zones with enhanced biodiversity. Yet, RCs employment on soft-beds could be improved by using more structured artificial frameworks, requiring further research efforts.
... The techniques of coral aquaculture are now well established for many species and locations (Shafir et al., 2006), and environmental and biological parameters affecting coral fragment growth and fitness have been well-documented (Shaish et al., 2010;Koval et al., 2020). Little is known, however, about the symbionts associated with cultivated coral fragments (Wee et al., 2019), despite their critical role in the functioning of natural coral ecosystems (Enochs, 2012). ...
... Existing literature suggests that symbionts settle on the host during the early stages of colony formation (Rouzéet al., 2019). Recent research has shown that relatively rich and abundant symbiotic fauna can be found in colonies of Pocillopora acuta, Platygyra sinensis, and Echinopora lamellosa just 5 months after their nursery rearing (Wee et al., 2019). This finding implies that coral farms, by establishing new microhabitats, can increase local biodiversity and contribute to the creation of new links in local food webs. ...
... Despite potential importance of ectosymbionts for understanding the ecological role of coral farms in natural ecosystems and in coral aquaculture management, little is known about their species composition and abundance in nursery-reared coral colonies (Wee et al., 2019). It is also unclear whether the species composition and abundance of symbionts on reared and natural coral colonies are similar. ...
Coral aquaculture techniques have been developed for many species based on a well-documented understanding of the factors that affect coral growth and fitness. However, there is limited knowledge about the composition and structure of ectosymbiotic communities associated with cultured coral colonies. To address this gap, we conducted a study of Pocillopora verrucosa colonies reared from fragments in fixed nurseries and exposed for 6 and 12 months, as well as natural colonies in the same location. Our analysis focused on the species composition, species richness, and abundance of obligate and facultative ectosymbionts associated with the colonies. Obtained results indicate that the community associated with nursery-reared colonies was highly diverse, comprising 25 ectosymbionts, including nine obligate and 16 facultative species. The prevalence, species richness, and density of the communities associated with natural colonies were significantly higher than those associated with reared ones. We also observed differences in the communities associated with reared colonies of different exposures, but we were able to group them as stages of the same community based on the size and exposure of the colonies. These differences may be related to the microhabitat properties of the symbiotic communities, as reared colonies were elevated above the substrate, while natural colonies were attached to them. The age of natural colonies was also estimated to be more than three times higher than that of reared colonies of the same size, also contributing to the differences. Our study clearly demonstrates that coral nurseries not only serve as a means of propagating corals but also offer artificial habitats for the maintenance and conservation of associated fauna. These findings have important implications for the management and conservation of coral reefs.
... The cryptofauna are composed of many different taxonomic groups of coral symbionts, whether facultative or obligate (Stella et al. 2011a), commensal, mutualistic or parasitic, with different ecological functions, and species that bore into the dead coral and rubble or utilize it for refuge (Fonseca et al. 2006;Enochs and Manzello 2012a, b;Cortés et al. 2017). More than 50% of invertebrate cryptofauna are obligate coral symbionts, including decapods such as Trapezid crabs and Alpheid shrimps (Stella et al. 2011a;Wee et al. 2019). Corals can receive various benefits from cryptofauna, such as protection and the removal of sediment from the colony (Pratchett et al. 2000;Pratchett 2001;Stewart et al. 2013;McKeon and Moore 2014;Wee et al. 2019). ...
... More than 50% of invertebrate cryptofauna are obligate coral symbionts, including decapods such as Trapezid crabs and Alpheid shrimps (Stella et al. 2011a;Wee et al. 2019). Corals can receive various benefits from cryptofauna, such as protection and the removal of sediment from the colony (Pratchett et al. 2000;Pratchett 2001;Stewart et al. 2013;McKeon and Moore 2014;Wee et al. 2019). As part of this symbiotic association, cryptofauna receive refuge from predators, space for recruitment, and food (Castro 1988;Stella et al. 2011b). ...
... When alive, coral colonies offer food resources such as mucus and nutrient-rich tissues, used by their obligate symbionts, such as Trapezia crabs (Knudsen 1967;Castro 1976;Rotjan and Lewis 2008). Once the coral colony dies and gets swiftly colonized by macroalgae and turf, the food resources available change, and so does the established cryptofauna community (Wee et al. 2019). This is congruent with the observed decrease in abundance of the decapods Trapezia and Alpheus, the main obligate symbionts of Pocillopora colonies, for the 2013-2014 period. ...
The cryptofauna are the small cryptic organisms that inhabit the interstices of coral colonies and have a great contribution to the biodiversity of the reef. Some of these species are vulnerable to environmental deterioration due to their dependency on living coral. In the 1990s, Culebra Bay, located in the North Pacific of Costa Rica, was considered one of the most important reef areas in the country, with a mean live coral cover over 40%. However, in the last two decades there was a drastic decrease in live coral cover to 5%, due to El Niño events and recurrent harmful phytoplankton blooms. To evaluate the effect of the deterioration of the reef on the cryptofauna, we compare two time periods: before (2003–2004) and after (2013–2014) coral decline. Pocillopora spp. colonies (~20 cm high by ~20 cm wide) were collected and all associated invertebrates removed. Twenty colonies were sampled each period. During the first period, sampled colonies were alive and healthy, whereas a decade later, exposed skeletons of dead colonies were sampled. A total of 3482 invertebrate individuals were found, belonging to 133 species, 72 families, and nine classes. While abundance and diversity were greater during the 2013–2014 period, we hypothesize that this is due to disturbance intensity being intermediate to high. If these conditions are persistent or intensify over time, however, we expect that once all substrate and reef structure is lost, an abrupt decline in cryptofauna abundance and diversity will take place. Reefs with dead corals therefore have a remarkably different composition of the cryptofauna. Obligate commensal fauna were replaced by boring, opportunistic, and facultative species in these habitats. These changes in live coral cover favored an increase in the diversity of organisms, but this enhanced diversity may be temporary as bioerosion reduces dead colonies to skeleton rubble. This change in the cryptofauna community can affect the recovery and sustainability of the reef ecosystem over time.
... Most studies evaluating factors that support or endanger biodiversity are based on the relation between reef fishes and corals, underestimating the importance of small invertebrates that compose the greatest number of species associated with corals (Stella et al., 2010(Stella et al., , 2011. Even if some studies have evaluated the influence of invertebrates, habitat structure has been characterized qualitatively (Wee et al., 2019) or simplified to only one structural variable (Vytopil & Willis, 2001). Efforts to quantify multiple elements of habitat structure influencing the associated fauna on corals are scarce, except for Stella et al. (2010) and Nogueira et al. (2015). ...
... Their establishment on coral hosts is influenced by coral morphology. This statement is based on evidence that the recruitment of epifaunal communities on corals is more influenced by habitat structure provided by coral morphology than by the presence of coral tissue (Wee et al., 2019). The framework provided by corals is a suitable habitat for a wide variety of benthic organisms that live in hard substrates, including molluscs (mainly bivalves and gastropods), which can be easily recognized living on corals and profiting in several different ways (Noseworthy et al., 2016). ...
... Based on this, Nogueira et al. (2015) identified the positive effects of habitat structure, indicating the most important structural variables influencing different crustacean orders, and proposed evaluations of different taxonomic groups in order to clarify such patterns. A multi-taxa evaluation is important because most studies in the literature concerning habitat structure and associated fauna deal only with crustaceans (Abele & Patton, 1976;Edwards & Emberton, 1980;Stella et al., 2010;Nogueira et al., 2015;Wee et al., 2019). ...
Habitat structure increases richness and abundance of species in many environments by providing easy access to resources and refuge from predators. In coral reefs, corals are habitat for many organisms and differences in their morphologies may act as variation in habitat structure for associated fauna. In the present study, we investigate whether there are differences in the richness and abundance of molluscs associated with three species of Mussismilia corals exhibiting different growth morphologies, in two different reef areas of the Bahia state. Mussismilia harttii has a meandroid pattern, M. hispida is a massive coral, M. braziliensis also has a massive growth pattern with crevices at the corallum base. Coral characteristics were measured in the laboratory. Significant differences were identified for richness among coral species – higher values were reported in colonies of M. harttii and no significant statistical differences were observed between M. braziliensis and M. hispida . Considering the density of associated molluscs, the same pattern was found. The results are in accordance with previous studies and indicate the importance of M. harttii as a key habitat to maintain a richer and more abundant associated fauna. The internal volume of interpolypal space is an important factor influencing the richness and density of associated species.
... Coral cryptofauna are composed of metazoan organisms living in inter-and intra-skeletal structures of hard corals, including dead corals and coral rubble (Enochs, 2011), and play an important role in maintaining coral reef functionality by capturing and recycling nutrients and providing biomass to upper trophic levels (Richter et al., 2001;Enochs, 2011;Kramer, Bellwood & Bellwood, 2013). Coral cryptofauna inhabit a variety of marine environments and have been used as proxies for benthic diversity in past studies (Takada, Abe & Shibuno, 2007;Enochs, 2011;Takada et al., 2014;Wee et al., 2019). Rubble cryptofaunal surveys can allow comparisons of the animal community living at each location in order to evaluate differences in biodiversity. ...
... The two datasets can be considered complementary, as the information they give integrate each other at different spatial scales and for different components of the coral reef community. Sampling coral rubble can provide a variety of data including abundances and diversity of cyptofaunal groups that are often overlooked when dealing with reef restoration, although rubble fauna data have been used before to study biodiversity in different environments (Takada et al., 2014) as well as in coral nurseries (Wee et al., 2019). ...
Global climate change is leading to damage and loss of coral reef ecosystems. On subtropical Okinawa Island in southwestern Japan, the prefectural government is working on coral reef restoration by outplanting coral colonies from family Acroporidae back to reefs after initially farming colonies inside protected nurseries. In order to establish a baseline for future comparisons, in this study we documented the current status of reefs undergoing outplanting at Okinawa Island, and nearby locations where no human manipulation has occurred. We examined three sites on the coast of Onna Village on the west coast of the island; each site included an outplanted and control location. We used (1) coral rubble sampling to measure and compare abundance and diversity of rubble cryptofauna; and (2) coral reef monitoring using Line Intercept Transects to track live coral coverage. Results showed that rubble shape had a positive correlation with the numbers of animals found within rubble themselves and may therefore constitute a reliable abundance predictor. Each outplanted location did not show differences with the corresponding control location in terms of rubble cryptofauna abundance, but outplanted locations had significantly lower coral coverage. Overall, differences between sites (Maeganeku1, Maeganeku2 and Manza, each including both outplanted and control locations) were significant, for both rubble cryptofauna and coral coverage. We recommend (1) to outplant colonies from more stress-resistant genera in place of Acropora, and (2) to conduct regular surveys to monitor the situation closely. With a lack of baseline data preceding impacts, rigorous monitoring over time can highlight trends towards increases or decreases in evaluated variables, allowing to obtain a clearer idea of the effects of transplants and on the trajectory of impacts due to climate change and local stressors. Finally, we also recommend (3) to establish conservation and sustainable practices that could aid the ongoing restoration efforts such as installing anchoring buoys to reduce impacts from anchoring, which could reduce coral mortality of both outplanted and native coral colonies.
... Species interactions can also help structure communities and even ecosystems; some key species create niches to help maintain local ecosystems. Corals reproduce by secreting calcium carbonate, creating complex three-dimensional structures that serve as habitat, altering sand's current speed and granulometry on the seabed, among other physical aspects of intertidal marine environments (Wee et al., 2019). Its action promotes shelter, as well as nurseries and attachment structures for species of algae, vertebrates, and marine invertebrates, and its effects extend beyond the physical limits of corals to the entire local marine ecosystem. ...
... nov., coincided with a high amount of mucus generated by the colonies (personal observations). Mucus production is a strategy adopted by corals to obtain protection against sedimentation, which also plays a role in the food chain of habitats generated by corals (Galil 1987;Vytopil and Willis 2001;Wee et al. 2019;Fraser et al. 2020). Thus, mucus can catch detritus and phytoplankton that facilitate the feeding of amphipods, as observed in decapod taxa that feed on particles trapped by coral mucus (Galil 1987). ...
Black corals are important components of mesophotic and deep-water marine habitats. Their presence at great depths (e.g., 50 to 200 m) makes accessibility difficult, limiting our understanding of the associated biodiversity. Amphipods dominate vagile epifauna in marine habitats around the world, fulfilling important ecosystem functions. However, there are no studies on amphipods exclusively associated with black corals, including relationships between their ecological patterns (e.g., abundances) and the size of coral colonies. We investigated the epifaunal composition and abundance associated with black coral colonies of Antipathella wollastoni in the subtropical eastern Atlantic Ocean. In total, 1,736 epifaunal individuals were identified, of which 1,706 (98.27%) were amphipods, belonging to 6 taxa. We identified and described a new amphipod genus and species within the Stenothoidae family, Wollastenothoe minuta gen. nov., sp. nov., which outnumbered the amphipod assemblage (86.15%) and provided a complete taxonomic key of Stenothoidae family including this new finding. For the first time, the association between an amphipod species and a black coral was described, including a strong correlation between coral colony size and amphipod abundances. This study demonstrates that epifauna associated with mesophotic black corals remains largely undescribed.
... Dense clusters of cuttlefish eggs were also deposited deep within coral branches, and juvenile cuttlefishes were seen seeking refuge around the Acropora aculeus and P. acuta colonies [46]. In addition, Wee et al. (2019) [47] reported that the nurseryreared corals also supported diverse epifaunal communities. From just 22 colonies of three coral species, 418 mobile invertebrates from 63 taxa such as crabs, shells, and shrimps were recorded. ...
... If a coral farm is located in an enclosed bay with natural water flowing through, gall crab larvae (megalopae) can potentially settle on corals intended for the international aquarium trade. Such coral farms, like coral nurseries, thus might become unintended reservoirs of coral-associated fauna [35,36]. ...
A new species of gall crab collected from elegance coral, Catalaphyllia jardinei, is described in this paper. The male holotype was collected from a reef tank in Germany in 2016, and it is described here using integrative taxonomy. This species, named Lithoscaptus aquarius sp. nov., is the thirteenth assigned to the genus. It is morphologically and phylogenetically closest to Lithoscaptus semperi, a cryptochirid associated with Trachyphyllia geoffroyi. Like L. semperi, it has a large, broad W-shaped depression on the anterior half of the carapace, but the carapace surface of L. aquarius sp. nov. is smooth overall, lacking spines or tubercles. This new species is so named because it was found in a reef tank after searching in vain for material during fieldwork campaigns over the course of several years.
... When placed in the nurseries the Acropora fragments are roughly finger-sized and thus presumably too small to already contain dwellings, hence shrimp larvae most likely settled on the fragments in the nurseries. A recent study shows that coral nurseries can support a diverse community of mobile epifauna (Wee et al. 2019). Our observations of P. siebenrocki in the Kenyan REEFolution nurseries highlight that these nurseries can also support populations of rarely reported immobile endofauna. ...
Tropical coral reefs offer a wide variety of habitats to countless invertebrate species. Sessile host organisms especially are inhabited by small taxa, of which decapod crustaceans form one of the most diverse communities. Symbiotic palaemonid shrimp species associate with marine invertebrate hosts from multiple phyla, including cnidarians such as stony corals (Scleractinia). The intriguing gall-forming shrimp Paratypton siebenrocki, a symbiont of Acropora corals in the Indo-Pacific, was collected in the Saudi Arabian Red Sea, Kenya, and the Maldives. Based on morphology P. siebenrocki has been considered to be most closely related to the genera Anapontonia and Metapontonia; however, no clear clustering with either palaemonid genus was observed in a phylogenetic reconstruction based on 16S and COI mtDNA. Here we photo-document the dwellings of P. siebenrocki in Acropora spp. for the first time, and furthermore we report on the reproductive output of this species. The number of eggs ranged from 345 to 909 (n = 6), and embryo volume differed strongly between early-and late-stage embryos. The carapace length ranged from 2.58 to 4.55 mm for the females and 1.51 to 2.5 mm for the males (n = 5). The number and size of the embryos, combined with their specialised, secluded lifestyle, suggest that P. siebenrocki allocates higher energy towards embryo production than free-living confamilials do. ARTICLE HISTORY
... Despite losing more than 60% of its original coral reef area, there remains considerable diversity, with over 30% coral cover along the shallow reef crests that extends to the lower depth limit of 5 m. Studies have recorded more than 250 hard coral species (Huang et al. 2009), nearly 200 fish species (Low and Chou 1994), and numerous invertebrate taxa (Wee et al. 2019). ...
In summary for Southeast Asia: Philippines.
Over the last decade, mean coral cover showed strong declining trends in the South Philippine Sea and the Sulu Sea, with marginal declines in the North Philippine Sea, Visayas Region (inland seas) and the Celebes Sea. Coral cover increased in the West Philippine Sea from 10% in 2008 to 32% in 2018. Overall, the cover data reported here are higher than a recent report by Licuanan et al. (2019), mainly because most of the sites surveyed here are located within marine protected areas. Between 2015 and 2017, coral bleaching was reported in 36 (54%) of the 66 coastal and island provinces surveyed. Most of the confirmed bleaching reports were in 2016 (79%), when bleaching incidences were reported almost year-round, although most reports (81%) were of low to mild bleaching. Moderate to severe coral bleaching was reported between April and October in 2016. The following year also saw bleaching, but reports were generally of low to mild bleaching.
... This highlights the complex and essential relationship in this ecosystem (Stella et al., 2011). Not just live branching corals, juvenile coral nurseries can support a range of epifaunal species and function as tools to conserve these threatened mobile species (Wee et al., 2019). More so, the biomass of seagrasses above-ground was noted to have significant attribution to epifaunal species composition, diversity, and productivity (Leopardas et al., 2014;Whippo et al., 2018). ...
Benthos is an encompassing term used to classify organisms found on, in, or in close contact to the bottom region of bodies of water. Benthic ecology, on the other hand, is the study of the relationships of benthos and their unique and diverse environment. This ecosystem is an abundant and valuable source of ecosystem goods and services that help sustain the ecosystem's healthy balance. The benthic infauna is the assemblage of organisms living within the seafloor, while the benthic epifauna is those living on or attached to the seafloor. These organisms are continuously threatened by various anthropogenic activities like bottom trawl fishing, mine tailing pollution, land reclamation and conversion, destruction of coralline and macroalgal communities, overexploitation, climate change, and many more. Due to their susceptibility and sensitivity, these organisms are often regarded as excellent bioindicators and biomonitors of environmental changes. This chapter attempts to introduce the complex world of the benthos and their vital role in the complex marine ecosystem. This chapter also presents current studies to understand further the ecology of benthos and the recent advances in research and technology.
... Thus, interspecific spatial partitioning for resources could be driving among-habitat distribution patterns for at least some species. Invertebrate-feeding labrids (except for H. nigrescens at Pulau Hantu) showed a general trend of higher feeding activity on reef flats at both study sites, probably due to the abundant and distinct epifaunal assemblages on reef flat substrates (Kramer et al., 2017;Wee et al., 2019). On the reef flat, scrapers were rare with no observed feeding activities. ...
Marine urbanisation often results in the proliferation of artificial coastal defences and heavy sedimentation, adversely impacting coral reef systems in tropical coastal cities. Knowledge of how motile organisms, such as reef fish, respond to novel human-made habitats and high sedimentation is limited. Here, we examine the role of sloping granite seawalls in supporting reef fishes that utilise the epilithic algal matrix (EAM) as a food resource. We surveyed fish assemblages and feeding activities on seawalls and reef flats, and conducted a field experiment to examine the effects of sediment on EAM feeding rates. Seawalls and reef flats supported distinct fish assemblage composition with significantly greater feeding activity on seawalls. However, reduced feeding activity on EAM with elevated sediment loads suggests that urban sedimentation may limit the utility of this novel feeding ground for nearshore communities. These findings illustrate the complexities and interactive effects of anthropogenic changes driven by coastal urbanisation.
... Organisms from the reef cryptofauna are essential for the functionality of coral reef ecosystems, both in terms of biomass (they constitute the largest part of reef 's diversity; Richter et al., 2001) and functionality, since they contribute to the aggregation and recycling of nutrients, providing biomass upwards in the trophic net (Richter et al., 2001;Kramer et al., 2013;Wolfe et al., 2020). Even coral rubble, dead coral skeletal frameworks detached from the substrate, has been shown to host a rich and diverse community and, for this reason, has been used as an indicator of reef diversity and environmental impact (Takada et al., 2014;Wee et al., 2019). When analyzing different reef substrates, Enochs and Manzello (2012b) observed that the highest richness in cryptofauna was surprisingly found within coral rubble, which hosted significantly higher cryptic diversity than healthy corals. ...
Substrate surface area and fractal complexity have been reported to influence the abundance and diversity of mobile cryptic animal communities. Surfaces with higher fractal dimensions not only offer additional space for colonization, but bias space availability toward smaller size ranges, increasing the number of available niches. Conversely, smaller surface areas tend to be associated with a decrease in abundances while reduced fractal complexities may support less diversity in the benthic community. In this study, we compared morphological parameters between rubble sampled from rubble mounds accumulated at the seaward side of artificial breakwaters and rubble sampled from a nearby location with no breakwaters (=control site). The purpose of this work was to establish a methodology for comparing the surface area and fractal complexity of coral rubble fragments using easily available equipment that could be efficiently utilized during field work. Rubble fragments were individually weighed and photographed in controlled light conditions. Each photograph was then analyzed using ImageJ software. Rubble pieces from each photograph went through segmentation, the separation of sample outlines from the picture background, before being measured and analyzed for surface area, width, and length (size estimators), and circularity, aspect ratio, roundness, solidity, and Feret properties (shape estimators). Surface fractal complexity was also measured, using the box counting method on segmented rubble surfaces. We observed lowered surface areas, weight, and fractal complexity for rubble fragments sampled at the breakwater. We demonstrate how this method could be used to compare coral rubble from a variety of environmental conditions, thus becoming a useful aid in environmental monitoring, in addition to adding important information to the collection and analyses of biological data.
... As uncontroversial as this definition of epifauna might seem, challenges nevertheless arise when undertaking a review of the topic, due to the use of alternative terminology to refer either to the same or similar groups of organisms within marine ecosystems. For example, many studies limit their classification of epifauna to mobile taxa only (Edgar 1990a, Martin-Smith 1993, Viejo & Åberg 2003, Arponen & Boström 2012, Bedini et al. 2014, Tano et al. 2016, Wee et al. 2019, Fraser et al. 2020a, whereas others include sessile organisms such as sea anemones, bryozoans and ascidians in their definition of epifauna (Shin 1981;Fowler & Laffoley 1993, Bradshaw et al. 2003, Hepburn et al. 2006, Demers et al. 2016, Kaiser et al. 2018. For reasons of historical legacy (the fact that most of the early studies of epifauna were based in temperate, deep sea habitats), some will think only of sessile, primarily planktivorous, invertebrates when using the term epifauna. ...
... Scleractinian corals are promising candidates for transplantation as they form the basis of reefs that many species depend on for survival (Burke et al., 2011;Graham et al., 2014). Once established, the biogenic habitat that corals create should attract and provide for other organisms such as fishes and molluscs (Cabaitan et al., 2008;Ng et al., 2015;Wee et al., 2019). Additionally, corals can potentially reduce wave energy and slow down erosion rates (Kunkel et al., 2006;Moberg and Folke, 1999). ...
Stony corals are promising transplant candidates for the ecological engineering of artificial coastal defences such as seawalls as they attract and host numerous other organisms. However, seawalls are exposed to a wide range of environmental stressors associated with periods of emersion during low tide such as desiccation and changes in salinity, temperature, and solar irradiance. All of these variables have known deleterious effects on coral physiology, growth, and fitness. In this study, we performed parallel experiments (in situ and ex situ) to examine among-genotype responses of Pocillopora acuta to emersion by quantifying growth, photophysiological metrics (Fv/Fm, non-photochemical quenching [NPQ], endosymbiont density, and chlorophyll [chl] a concentration) and survival, following different emersion periods. Results showed that coral fragments emersed for longer durations (> 2 h) exhibited reduced growth and survival. Endosymbiont density and NPQ, but not Fv/Fm and chl a concentration, varied significantly among genotypes across different durations of emersion. Overall, the ability of P. acuta to tolerate emersion for up to two hours indicates it has potential to serve as a ‘starter species’ for transplantation efforts on seawalls. Further, careful characterisation and selection of genotypes with a high capacity to withstand emersion can help maximise the efficacy of ecological engineering using coral transplants.
... There is still a wide range of ecological engineering tactics as of yet unfounded by research. One example is engineering of the diversity of the coral cryptofauna, the metazoan organisms residing between branches and cervices of coral structures, and those residing within the corals' hard skeleton, as well as the cryptofauna dwelling in coral rubble and in corals farmed within coral nurseries Enochs, 2012;Takada et al., 2014;Wee et al., 2019). All these may also be used as proxies for management strategies, since they are associated with major roles in reef functionality and trophic webs. ...
The combined accelerated footprint of climate change and enhanced anthropogenic pressures and the poor outcomes of many traditional management activities raise the needs for active reef restoration tactics (targeting coral mariculture/transplantation), backed by ecological engineering approaches. These approaches include, among others, the use of ecosystem engineer species, which, through modifications in their physical or biological properties, they create new habitats characterized by novel biodiversity (through either autogeny or allogeny engineering acts). Only a small number of studies on coral reef restoration have discussed/mentioned “ecological engineering” or “coral reef engineering”. Examining reef restoration publications (2016–2019; 145 publications) reveals only 39 (26.9%) dealing with ecological engineering aspects, with 10 classes of “applications” (26 publications) and 4 classes of “properties” (n = 13). Ecological engineering “applications” incorporate all aspects of reef restoration, while the ecological engineering “properties” deal with assisted genetics, coral chimerism, aqua-culturing reef-dwelling organisms, and the consideration of life history parameters of maricultured/transplanted key species. Yet, many ecological engineering applications focus on particular coral species, addressing their specific community issues, while only few address the needs of the entire ecosystem/landscape restoration. It is concluded that rather than trying to return ecosystems to historic states, ecological engineering should shift towards creating novel ecosystems not existed before.
The “coral gardening” approach has been effective in facilitating the recovery of degraded reefs but methodological variations can influence survivorship and growth of the coral material. In addition, the disproportionate use of certain corals, such as acroporids and pocilloporids, has contributed to a general lack of information on growth patterns and restoration strategies for species that are less common. To investigate how the yield of other species may be increased to support reef restoration efforts in Singapore, we assessed the effects of (1) environment (nursery, reef, and seawall) and (2) transplant orientation (horizontal and vertical) on the performance of Echinopora horrida (Dana, 1846) fragments. Fragments secured in the coral nursery grew significantly faster and survived better than those transplanted on the reef and seawall, highlighting the importance of a nursery‐rearing phase in optimizing the yield of this species. Additionally, survivorship and growth rates were not significantly different between vertically and horizontally transplanted corals, suggesting that modifying transplant orientation was less crucial toward enhancing coral yield. Our findings highlighted the need to optimize the propagation techniques of a wider range of understudied coral species in order to preserve their genetic diversity in the face of anthropogenic and climatic impacts.
Shoreline armouring has progressively affected the coastal landscapes of countries all over the world, and armouring construction will increase in coming years as a consequence of climate change. Armouring has the potential to affect coastal environments and induce changes in the abundance and diversity of marine communities, and its effects might by increased by wide adoption. Moreover, compared with temperate locations, the effects of armouring have been less studied in tropical and subtropical areas. Okinawa Island, the largest and most populated island of the Ryukyu Archipelago in southern Japan, has been affected by numerous civil and military engineering works. After decades of development, less than 40% of its coastline remains natural, and yet impacts from armouring on local marine communities have been overlooked until recent years. The aim of this research was to evaluate effects of near-shore armouring on the surrounding environment by comparing diversity and abundance of coral rubble mobile cryptofauna benthic communities between armoured and control sites. Across six different geographic locations, coral rubble was sampled in front of subtidal breakwaters and at nearby control sites. Armoured sites were associated with lower cryptofauna abundances and reduced richness and diversity at higher taxonomic levels (phylum and class). Reduction in spatial complexity could be a plausible reason for the observed patterns. Impacts could be mitigated by combining technical innovations, habitat restoration, and use of natural spaces as buffers for coastal protection. Since less than half of Okinawa Island’s coastline remains in a natural state, environmental conservation should be prioritized.
Urbanization of coastal cities has resulted in extensive physical modification of the coast that is commonly accompanied by habitat destruction or degradation, marine biodiversity loss and ecosystem services decline. Conversion of the natural environment to a human-modified one is often permanent, and it is important that development considerations take into account biodiversity enhancement of the ‘new’ environment. Development of biological communities in the modified environment takes time and is unlikely to return to levels once supported by the original habitats, but efforts can be made to facilitate the establishment of biodiversity that is suited to the new environmental conditions. Active interventions such as water quality management and ecological restoration can help to transform the urbanized coastal environment into a suitable biodiversity support zone. Observations of marine biodiversity in marinas and restoration of corals on artificial structures in Singapore support this prospect. Assessment of the biodiversity in three marinas indicated that they can function as marine biodiversity refugia, especially with their relatively high artificial structural complexity and when designed with basic ecological considerations to enhance marine biodiversity. Separately, reef restoration projects give rise to the possibility of colonizing seawalls with corals and other reef-associated species, as well as improving degraded reefs and creating reef communities in areas originally devoid of corals due to the heavy sediment load of urbanized coastal waters. Maintaining marine biodiversity in challenging environmental conditions resulting from urbanization can help to ensure continued provision of some level of ecosystem services.
Global climate change is leading to damage and loss of coral reef ecosystems. On subtropical Okinawa Island in southwestern Japan, the prefectural government is working on coral reef restoration by outplanting coral colonies from family Acroporidae back to reefs after initially farming colonies inside protected nurseries. In this study we evaluated the ongoing restoration efforts by comparing outplanted locations with nearby control locations with no restoration activity. We examined 3 sites on the coast of Onna Village on the west coast of the island; each site included an outplanted and control location. We used 1) coral rubble sampling to evaluate and compare abundance and diversity of rubble cryptofauna; and 2) coral reef monitoring using photograph transects to track live coral coverage. Results showed that rubble shape had a positive correlation with the numbers of animals found within rubble themselves and may therefore constitute a reliable abundance predictor. Outplanted locations did not show differences with the controls in rubble cryptofauna abundance, but had significantly lower coral coverage. Differences between sites were significant, for both rubble cryptofauna and coral coverage.We recommend; 1) to evaluate outplanting colonies from more stress-resistant genera in place of Acropora , 2) to conduct regular surveys to monitor the situation closely, and 3) to establish conservation and sustainable practices that could aid restoration efforts, reducing coral mortality of both outplanted and native colonies.
Global climate change is leading to damage and loss of coral reef ecosystems. On subtropical Okinawa Island in southwestern Japan, the prefectural government is working on coral reef restoration by outplanting coral colonies from family Acroporidae back to reefs after initially farming colonies inside protected nurseries. In this study we evaluated the ongoing restoration efforts by comparing outplanted locations with nearby control locations with no restoration activity. We examined 3 sites on the coast of Onna Village on the west coast of the island; each site included an outplanted and control location. We used 1) coral rubble sampling to evaluate and compare abundance and diversity of rubble cryptofauna; and 2) coral reef monitoring using photograph transects to track live coral coverage. Results showed that rubble shape had a positive correlation with the numbers of animals found within rubble themselves and may therefore constitute a reliable abundance predictor. Outplanted locations did not show differences with the controls in rubble cryptofauna abundance, but had significantly lower coral coverage. Differences between sites were significant, for both rubble cryptofauna and coral coverage.We recommend; 1) to evaluate outplanting colonies from more stress-resistant genera in place of Acropora , 2) to conduct regular surveys to monitor the situation closely, and 3) to establish conservation and sustainable practices that could aid restoration efforts, reducing coral mortality of both outplanted and native colonies.
Population outbreaks of corallivorous Drupella gastropods have caused mass coral mortality, but there is insufficient information on their feeding behaviour to develop useful reef management strategies. This study examined the feeding rates of two Drupella species, D. rugosa (Born 1778) and D. margariticola (Broderip 1833), and investigated whether the presence of the coral guard crab, Trapezia cymodoce (Herbst 1801), could help to reduce corallivory on Pocillopora acuta (Lamarck 1816). Our mesocosm study showed that the feeding rate of D. rugosa (1.81 ± 0.95 cm2 coral tissue/day) was significantly higher than that of D. margariticola (0.51 ± 0.75 cm2 coral tissue/day). The presence of T. cymodoce reduced the feeding rate of D. rugosa by 22.9%; this was lower than that by other Trapezia congenerics. Trapezia cymodoce also did not display much aggressive behaviour towards D. rugosa. This study has highlighted that D. rugosa can cause considerable damage to corals and defence by T. cymodoce alone is unlikely to be effective against Drupella corallivory. Early detection of Drupella outbreaks and the subsequent development of mitigation measures remain of paramount importance in reducing the impact of corallivory on coral reefs.
In situ nurseries have been a crucial part of coral reef restoration initiatives for the past two decades. However, the advantages over direct transplantation in sedimented waters has yet to be examined. In the present study, we showed that Pachyseris speciosa and Pocillopora damicornis fragments reared in in situ nurseries (NR) in Singapore’s sedimented waters grew significantly faster (by three to five times) than those which were directly transplanted (DT) onto the substrates. The increased growth rate during the nursery phase augmented the size of NR transplants, and had a flow-on effect on their performance during the post-transplantation phase. Overall, the maximum diameter of the NR transplants was 1.8–2.7 times larger than DT transplants after 11 months. The growth enhancement of the nursery-reared transplants improved the cost-effectiveness of our restoration effort: the estimated cost per centimetre growth of NR transplants was one-fifth of the DT corals despite the additional costs incurred to construct the nurseries. These results highlight that coral nurseries are beneficial to reef restoration in chronically sedimented waters.
Despite the increasing need to understand factors shaping community assembly, few studies have simultaneously explored the influence of niche-based and phylogenetic processes. Here, we investigate the relationships between diet, habitat and social behaviour in damselfishes (Pomacentridae) collected in 2014 at Moorea Island (17°30′S, 149°50′W), French Polynesia. Isotope ratios of carbon and nitrogen, in association with stomach contents, delineate three trophic groups: pelagic feeders consuming zooplankton, benthic feeders mainly grazing on algae and an intermediate group feeding on prey from the whole bentho-pelagic compartment. Sulphur isotope ratios indicate segregation between species of the outer reef mostly depending on oceanic input of zooplankton and the lagoonal species relying on locally produced resources or even on terrestrial supply. We demonstrate a tight association between dietary specializations, habitat characteristics and social behaviours, and these correlations are further confirmed by integrating the phylogeny of Pomacentridae. We also provide evidence of phylogenetic conservatism for the stomach content and the habitat–behaviour characters. However, the isotopic trait is evolutionarily more labile probably because it thoroughly depicts the ecological niche of species. To summarize, pelagic feeders (mainly from the Chrominae) usually form shoals in areas close to the open ocean at a maximum depth of 20 m. Benthic feeders (well represented in the Stegastinae) are ubiquitous, solitary and mostly territorial species found at various depths. The intermediate group includes gregarious species from three subfamilies that forage in the lagoon usually above 12 m depth. Overall, we give insight into processes that have structured the damselfish community in Moorea.
The present checklist represents a synthesis of the current state of knowledge of the caridean shrimp fauna of Singapore, based mainly on the abundant material collected in the Straits of Johor and Strait of Singapore during the Comprehensive Marine Biodiversity Survey of Singapore (CMBS) in 2010–2014. Some additional caridean material from Singapore, for instance, material collected and identified by D.S. Johnson in the 1950–1960s, were also included. All reported taxa are listed with selected synonymy, as well as taxonomic, ecological and biogeographical notes; most species are also illustrated in colour, some for the first time. Many taxa, especially in the family Alpheidae, represent taxonomically challenging species complexes that may each take several years to be completely resolved. The material collected during CMBS contains a total of 128 taxa (including well-defined species, tentatively identified species (cf., aff.), and species complexes = species sensu lato) in 53 genera and 12 families. Species previously reported from Singapore but not re-collected by CMBS are included in a table summarising all caridean records from the country, totalling 219 taxa in 63 genera and 14 families; however, some of these records appear to be questionable and require confirmation. A total of 47 caridean species are recorded from Singapore for the first time, the most notable new records being, for the Alpheidae: Alpheus ehlersii De Man, 1909; Automate anacanthopus De Man, 1910; Prionalpheus sulu Banner & Banner, 1971; Salmoneus seticheles Anker, 2003 (previously known only from northern Australia); S. alpheophilus Anker & Marin, 2006; Synalpheus thai Banner & Banner, 1966; Thuylamea camelus Nguyên, 2001 (genus and species previously known only from Vietnam); for the Palaemonidae: Periclimenaeus arabicus (Calman, 1939); P. orontes Bruce, 1986 (previously known only from northern Australia); Pontonides loloata Bruce, 2005; and for the remaining families: Latreutes anoplonyx Kemp, 1914; Leptochela crosnieri Hayashi, 1995 (previously known only from New Caledonia); Lysmata lipkei Okuno & Fiedler, 2010 (previously known only from Japan); Ogyrides orientalis (Stimpson, 1860); Philocheras pilosus (Kemp, 1916) and Thor marguitae Bruce, 1978 (previously known only from eastern Australia). Taxonomic changes are made for Alpheus dispar Randall, 1840 (previously considered a synonym of A. brevirostris (Olivier, 1811)), A. imitatrix De Man, 1909b (previously considered a subspecies of A. pareuchirus Coutière, 1905) and A. monoceros Heller, 1862 which is herein formally considered to be a nomen dubium.
In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies of
Acropora cervicornis
to estimate geometry (length and height), structural complexity (i.e., volume, density of branches, etc.) and biological features of the colonies (i.e., live coral tissue, algae). We then correlated these colony characteristics with the associated fish assemblage using multivariate analyses. We found that geometry and complexity were better predictors of the structure of fish community, compared to other variables such as percentage of live coral tissue or algae. Combined, the geometry of each colony explained 40% of the variability of the fish assemblage structure associated with this coral species; 61% of the abundance and 69% of fish richness, respectively. Our study shows that three-dimensional reconstructions of discrete colonies of
Acropora cervicornis
provides a useful description of the colonial structural complexity and may explain a great deal of the variance in the structure of the associated coral reef fish community. This demonstration of the strongly trait-dependent ecosystem role of this threatened species has important implications for restoration and conservation efforts.
Coral habitat structures increase abundance and richness of organisms by providing niches, easy access to resources and refuge from predators. Corals harbor a great variety of animals; the variation in coral species morphology contributes to the heterogeneity and complexity of habitat types. In this report, we studied the richness and abundance of crustaceans (Decapoda, Copepoda, Peracarida and Ostracoda) associated with three species of Mussismilia exhibiting different growth morphologies, in two different coral reefs of the Bahia state (Caramuanas and Boipeba-Moreré, Brazil). Mussismilia hispida is a massive coral; M. braziliensis also has a massive growth pattern, but forms a crevice in the basal area of the corallum; M. harttii has a meandroid pattern. PERMANOVA analysis suggests significant differences in associated fauna richness among Mussismilia species, with higher values for M. harttii, followed by M. braziliensis and later by M. hispida. The same trend was observed for density, except that the comparison of M. braziliensis and M. hispida did not show differences. Redundancy and canonical correspondence analysis indicated that almost all of the crustacean species were more associated with the M. harttii colonies that formed a group clearly separated from colonies of M. braziliensis and M. hispida. We also found that the internal volume of interpolyp space, only present in M. harttii, was the most important factor influencing richness and abundance of all analyzed orders of crustaceans.
Isopoda are the most diverse Crustacea. In order to encourage the study of isopod crustaceans and their use in biodiversity studies, systematics, ecology, physiology and more, one needs to know who the isopods are and where to find them.
This is a short "how to" guide focusing on the free-living marine and freshwater isopods: where they live and how to collect and preserve them. The tools and techniques described here are simple, but invaluable in accessing the natural history of these remarkable creatures.
Anomuran and brachyuran crab symbionts from 51 colonies of corals belonging to the families Acroporidae, Agariciidae and Pocilloporidae were investigated. A total of seven species of anomurans and 27 species of brachyurans were collected, of which the majority were corallophilous symbionts. Comparisons with studies made at four oceanic reefs revealed a paucity of brachyuran corallicolous symbionts, with only four species of Anomura and
four species of Brachyura observed in Singapore. However, there was a high abundance of corallophilous and casual symbionts in Singapore.
The present study (Ishigaki Island, Japan) explored the distance of transmission of chemical cues
emitted by live versus dead coral reefs (Exp. 1: High performance liquid chromatography (HPLC) analyses with water sampling station at 0, 1, and 2 km away from the reef) and the potential attraction of these chemical cues by larval fish, crustaceans, and cephalopods (Exp. 2: choice flume experiment conducted on 54 Chromis viridis larvae, 52 Palaemonidae sp larvae, and 16 Sepia latimanus larvae).
In the experiment 1, HPLC analyses highlighted that the live coral reef (and not the dead coral reef) produced different and distinct molecules, and some of these molecules could be transported to a distance of at least 2 km from the reef with a reduction of concentration by 14–17-fold. In the experiment 2, C. viridis, Palaemonidae sp, and S. latimanuslarvae were significantly attracted by chemical cues from a live coral reef (sampling station: 0 km), but not from a dead coral reef. However, only C. viridis larvae detected the chemical cues until 1 km away from the live coral reef. Overall, our study showed that chemical cues emitted by a live coral reef were transported farthest away in the ocean (at least 2 km) compared to those from a dead coral reef and that fish larvae could detect these cues until 1 km. These results support the assumption of a larval settlement ineffective in degraded coral reefs, which will assist con-servationists and reef managers concerned with maintain-ing biodiversity on reefs that are becoming increasingly degraded.
Forty-three species have been assigned to Pilodius . This revision accepts 12 and, in addition, establishes three new species. These 15 species are described, figured, and their distributions mapped. A key to the genus is provided.
Size-dependant mortality influences the recolonization success of juvenile corals transplanted for reef restoration and assisting juvenile corals attain a refuge size would thus improve post-transplantation survivorship. To explore colony size augmentation strategies, recruits of the scleractinian coral Pocillopora damicornis were fed with live Artemia salina nauplii twice a week for 24 weeks in an ex situ coral nursery. Fed recruits grew significantly faster than unfed ones, with corals in the 3600, 1800, 600 and 0 (control) nauplii/L groups exhibiting volumetric growth rates of 10.65±1.46, 4.69±0.9, 3.64±0.55 and 1.18±0.37 mm3/week, respectively. Corals supplied with the highest density of nauplii increased their ecological volume by more than 74 times their initial size, achieving a mean final volume of 248.38±33.44 mm3. The benefits of feeding were apparent even after transplantation to the reef. The corals in the 3600, 1800, 600 and 0 nauplii/L groups grew to final sizes of 4875±260 mm3, 2036±627 mm3, 1066±70 mm3 and 512±116 mm3, respectively. The fed corals had significantly higher survival rates than the unfed ones after transplantation (63%, 59%, 56% and 38% for the 3600, 1800, 600 and 0 nauplii/L treatments respectively). Additionally, cost-effectiveness analysis revealed that the costs per unit volumetric growth were drastically reduced with increasing feed densities. Corals fed with the highest density of nauplii were the most cost-effective (US$0.02/mm3), and were more than 12 times cheaper than the controls. This study demonstrated that nutrition enhancement can augment coral growth and post-transplantation survival, and is a biologically and economically viable option that can be used to supplement existing coral mariculture procedures and enhance reef restoration outcomes.
While the loss of structural complexity causes declines in coral reef fish diversity, the processes leading to this decline are largely unexplained. To explore the role of coral morphology in providing shelter for fishes, tabular, branching and massive corals were filmed with video cameras and their usage by large reef fishes compared. Tabular corals were utilised more than the other two morphologies, with at least triple the abundance, biomass and residence times of large fishes. The preference of coral reef fishes for specific structural traits of tabular corals was also examined using artificial structural units. This experimental component showed that large reef fishes preferred opaque rather than translucent canopies. It appears that large fishes cue to tabular corals because of the concealment and/or shade provided. It is suggested that a loss of tabular corals as a result of climate change would have significant ecological impacts for the coral reef fishes that use these structures for shelter.
The importance of structural complexity in coral reefs has come to the fore with the global degradation of reef condition; however, the limited scale and replication of many studies have restricted our understanding of the role of complexity in the ecosystem. We qualitatively and quantitatively (where sufficient standardised data were available) assess the literature regarding the role of structural complexity in coral reef ecosystems. A rapidly increasing number of publications have studied the role of complexity in reef ecosystems over the past four decades, with a concomitant increase in the diversity of methods used to quantify structure. Quantitative analyses of existing data indicate a strong negative relationship between structural complexity and algal cover, which may reflect the important role complexity plays in enhancing herbivory by reef fishes. The cover of total live coral and branching coral was positively correlated with structural complexity. These habitat attributes may be creating much of the structure, resulting in a collinear relationship; however, there is also evidence of enhanced coral recovery from disturbances where structural complexity is high. Urchin densities were negatively correlated with structural complexity; a relationship that may be driven by urchins eroding reef structure or by their gregarious behaviour when in open space. There was a strong positive relationship between structural complexity and fish density and biomass, likely mediated through density-dependent competition and refuge from predation. More variable responses were found when assessing individual fish families, with all families examined displaying a positive relationship to structural complexity, but only half of these relationships were significant. Although only corroborated with qualitative data, structural complexity also seems to have a positive effect on two ecosystem services: tourism and shoreline protection. Clearly, structural complexity is an integral component of coral reef ecosystems, and it should be incorporated into monitoring programs and management objectives.
Transplanting nursery-reared corals is among one of the most common approaches to assist the recovery of degraded reefs. The nursery phase is considered essential for providing a favourable environment for coral fragments to grow into suitable sizes before transplantation to natural reef substrates. Several types of coral nursery designs have been used, but the effect of nursery table slope orientation on survival and growth of coral fragments has not been fully evaluated. Survival and growth of coral fragments from four species (Pectinia paeonia, Podabacia crustacea, Pocillopora acuta, Merulina ampliata) on three inclinations of nursery table top (horizontal (0°), diagonal (45°) and vertical (90°)) were monitored over six months. The effects of slope orientation on survival and growth of fragments were not significant among species except P. acuta, for which survivorship and growth decreased significantly only on vertical nursery tables. The conditions required for coral propagation, such as slope orientation of nursery tables and the initial size of fragments, clearly differ among species due to their inherent attributes and restoration success will greatly benefit from empirical studies derived from a wider range of species.
Artificial reefs provide substrates that facilitate the rapid recruitment of marine biota such as corals and fish, and are commonly employed as coral restoration tools to assist recovery in degraded areas. While this strategy is successful in the immediate years post‐deployment, its contribution to restoration over longer time scales is less well understood.
The biological communities on Reef Enhancement Units (REUs), which had been deployed for more than a decade on Singapore's sediment‐affected coral reefs, were surveyed.
The diversity of sessile lifeforms on the REUs was significantly higher in 2014 (H′ = 1.03) than 2004 (H′ = 0.60). Hard corals and coralline algae contributed most to the temporal dissimilarity and turf algae remained the dominant lifeform category in both years.
In 2014, hard corals and abiotic components contributed most to the spatial dissimilarity among the six REU plots that were surveyed. Shannon diversity values of these plots ranged from 0.74–1.3. Scleractinian cover ranged from 0.4–31.5% and differed significantly among the plots.
The REUs also augmented ecosystem functioning at their respective plots. Colonies from 10 of the 30 scleractinian genera recorded were sexually mature, and a total of 119 sessile and mobile reef taxa utilized the REUs for food and habitat.
The results demonstrate that artificial reefs can contribute to the development of biological communities and ecosystem functioning in degraded coral habitats over the long run, and underscore the need for long‐term monitoring to validate the effectiveness of reef restoration efforts.
Seawalls, which have replaced many natural shorelines in coastal cities, are increasingly built to alleviate the impacts of rising sea levels. To mitigate the consequential loss of biodiversity, novel approaches such as ecological engineering have been adopted to enhance the biodiversity on these artificial structures. However, the majority of research to date has focused on physical modifications of intertidal seawalls, and such habitat enhancement efforts are labour- and cost-intensive. We examined the feasibility of transplanting nursery-reared scleractinian corals on subtidal seawalls in Singapore with the help of volunteers. Fragments of six hard coral species (Pocillopora damicornis, Hydnophora rigida, Merulina ampliata, Podabacia crustacea, Echinopora lamellosa, Platygyra sinensis) were tested. Fragments of all species fared well in the nurseries with a mean survival rate of 98.5% and 1.1 to 4-fold increase in live tissue area. Six months after transplantation to a seawall, only 50% of P. damicornis transplants survived, while those of M. ampliata decreased in size. Transplants of the other four species exhibited sustained growth and high survival rates (>90%), suggesting that they were more suitable than the former two species as candidates for transplantation onto subtidal seawalls. Scleractinian cover at the transplant site increased from 3% to 20% and generic richness increased from two to eight. The estimated project costs were almost US$ 23,000 if only researchers were involved in the effort, but the inclusion of volunteers in fieldwork and data analyses could help to bring the expenditure down by up to 23%. The study demonstrated the feasibility of transplanting corals onto subtidal seawalls to mitigate the impacts of coastal development, and highlighted its potential for application on other artificial structures. The findings also show that synergy between the community and scientists helps to reduce overall costs and is beneficial for biodiversity enhancement initiatives.
Brittlestars were collected from the intertidal seashore by hand, and from the subtidal seabed using dredges and trawls as well as by scuba diving around St. John’s Island in the Singapore Strait, during the Workshop from 20 May to 7 June 2013. Five species in two ophiurine families of brittlestars Ophiodermatidae and Ophiolepididae were identified from the Strait of Singapore. The Ophiodermatidae comprised Ophiarachnella gorgonia, Ophioconis permixta, and Ophiodyscrita instrata. The latter two ophiodermatid species were new records for Singapore. The Ophiolepididae identified were Ophiolepis cincta cincta and Ophiolepis nodosa. Members of the two families appear to be confined to the Singapore Strait and were not found in the Johor Straits.
Singapore’s coral reefs have been exposed to five decades of increased sedimentation that reduced underwater visibility from over 10 m in the early 1960s to under 2 m today. The lower depth limit of scleractinian coral growth moved up from 10 m to 6 m, while live coral cover decline is less apparent now than in the early decades of augmented sediment loading. Coral community structure has changed with dominance shifting to more low-light tolerant species such as those of the genera Pectinia and Turbinaria. Reef restoration to increase coral cover of degraded reefs and initiate colonization of non-reef areas is considered to be viable following observations of predictable mass spawning events, recruitment and vigorous growth, but the techniques employed need to account for the high sediment conditions and destabilized reef substrate. The deployment of fibreglass artificial reef units increased opportunities for coral establishment, and supported at least 106 reef taxa, including 29 scleractinian genera after 10 years. As vital components of restoration, coral nurseries comprising mesh-net platforms raised above the reef floor prevented sediment accumulation and smothering, and enabled the rearing of coral fragments and juveniles with reduced mortality. This included the nurturing of ‘corals of opportunity’ (naturally fragmented pieces of live coral lying on the reef bed as well as recruits settled on loose rubble), which would otherwise be killed by sedimentation. Transplants of massive or encrusting species displayed higher survival over branching ones. Restoration strategies need to be adapted to changed environmental conditions caused by anthropogenic disturbances.
A new species of pontoniine shrimp, Cuapetes takedai sp. nov., is described and illustrated on the basis of five specimens from Suruga Bay, Honshu, Japan. The new species is closely related to C. nilandensis (Borradaile) on account of the lack of meral and ischial distoventral teeth on the second pereiopod and the presence of elongate distoventral spines on the propodi of the ambulatory pereiopods, but can be readily distinguished from the latter species by the lack of a supraorbital spine and the carpus of the second pereiopod being considerably longer than the palm. The new species is associated with the hydroid, Lytocarpia Niger (Nutting) and an unidentified gorgonarian.
The spider crab Doclea johnsoni Ow-Yang, in Lovett, 1981, is shown to be a junior subjective synonym of D. canaliformis Ow-Yang, in Lovett, 1981. Hyastenus trispinosus Rathbun, 1916, is also synonymised under H. subinermis Zehntner, 1894. The geographical distribution of Hyastenus cracentis Griffin & Tranter, 1986, and H. elatus Griffin & Tranter, 1986, are also extended to Hong Kong and Singapore respectively.
The natural coral reef resources degrade rapidly because of climate change, environmental pollution and exploitation of aquarium species. Artificial propagation is an effective way to facilitate the reduction of wild harvesting, reef restoration, preservation of biodiversity. This paper reviewed the technique and research progresses focused on coral artificial propagation. We compared the advantages and disadvantages of sexual reproduction and asexual reproduction as well as in situ and ex situ propagation. Moreover, we summarized the important roles of irradiation, flow rate, nutrients, feed and other factors in coral propagation within recirculating aquaculture system (RAS). Irradiation is the key to successful ex situ coral culture and different species show different needs of radiation intensity and light spectrum. Therefore, artificial lighting in RAS, as well as power and maintenance costs, are very important for ex situ coral aquaculture. In addition, corals are very sensitive to NH4+, NO3-, NO2- as well as phosphate in RAS, and many physical, chemical and biological methods are acquired to maintain low nutrients condition. Although RAS has progressed a lot in terms of irradiation, flow rate and nutrient control, future studies also should focus on sexual reproduction, genetic modification and disease control. ©, 2015, Editorial Board of Chinese Journal of Applied Ecology. All right reserved.
The stylodactylid shrimps are reviewed, with keys to the three genera currently recognized. Sixteen species are treated, including three new species ofStylodactylus: S. libratus from Celebes, Indonesia, S. licinus from Palawan Passage, Philippines, and S. macropus from north of Samar, Philippines. Examination of male specimens, including the holotype, of Neostylodactylus amarynthis revealed that there are four large arthrobranchs in the gill series of males in this, the type-species of the genus, whereas arthrobranchs are quite lacking in females assigned to the same species.
Coral transplantation has become a potential tool for the restoration of coral cover in degraded reef habitats. Yet, very few investigations have attempted to determine whether there is an advantage for at least two species to be used together in coral transplantation. It is hypothesized that corals would perform better in terms of survival and growth when transplanted in mixed- than in single-species plots. Single-species plots were compared with combinations of two species at several reef sites, using three separate coral species, namely, Porites cylindrica, Pavona frondifera, and Hydnophora rigida. P. cylindrica performed consistently well in terms of survival whether alone or in the presence of another species. In a stressful environment with strong wave action, P. frondifera performed better when mixed with P. cylindrica than when alone. However, this difference was not evident where wave action was weak. The influence of mixing on the growth rates of H. rigida and P. frondifera transplants could not be examined completely because of high mortality because of predation by the starfish Acanthaster planci and the gastropod Drupella sp. Interestingly, the presence of P. cylindrica appeared to minimize the impact of predation on P. frondifera transplants. The setback caused by predation stresses the importance of other factors that influence the outcome of restoration interventions. Future initiatives should take into consideration management measures when selecting sites in relation to wave action and predators, control predator outbreaks, and use coral species, e.g. P. cylindrica that are less susceptible to predation.
Various physical and biological factors affecting coral community structure were investigated by direct observation and periodic censusing (supplemented with laboratory observations and experiments) on three coral reefs off the Pacific coast of Panama from 1970 to 1975. The physical environment has a strong control over coral growth at shallow depth; physical factors are also important subtidally (light, sediment transport). However, paralleling the pattern on temperate shores, biological processes (competition, predation, bioturbation, mutualism) assume an increasing influence on community structure in deeper and more diverse reef assemblages. Coral zonation is marked on these biologically simple and small reefs; the following assemblages are recognized: drying reef flat--live coral cover moderate, species diversity low; reef crest and upper reef slope--highest cover, lowest diversity; lower reef slope and reef base--cover moderate to low, diversity highest. Coral populations in the different zones, though spatially close, are affected by unique sets of conditions. Recurrent extreme tidal exposures devastate reef flat corals (Pocillopora mortality = 40%-60%). The mortality rate of pocilloporid corals is higher than for other corals; this has a diversifying effect on the reef flat assemblage. Acanthaster normally feeds in deep reef zones and numerically its major prey are the predominant pocilloporid corals (most often small colonies and broken branches). Electivity indices and prey choice experiments indicate that less abundant, nonbranching corals are preferred over Pocillopora. Large, branching pocilloporid colonies harbor crustacean symbionts (Trapezia and Alpheus) which can repulse Acanthaster and therefore protect this group of corals. Experimental removal of the symbionts results in a shift of prey preference from nonbranching corals towards the branching pocilloporids. Crustacean symbionts were present in all large Pocillopora colonies sampled, but the density of Trapezia in colonies on the reef flat was about twice that in colonies from deep zones where Acanthaster forages. Further, small pocilloporid colonies and fragments contained relatively few (and a high proportion of juvenile) symbionts. The variety of preferred coral prey present along the seaward reef flanks and the relatively low abundance of Pocillopora in this habitat are considered important factors affecting the distribution of Acanthaster. In addition, a continuous live cover of pocilloporid corals, which Acanthaster avoids, can protect reef zones (e.g., the reef flat) or preferred prey species from attack. The selective destruction of nonpocilloporid corals by Acanthaster tends to lower both live coral cover and species diversity (H'). This trend is evident on the Uva Island study reef where a significant decline in coral cover (47%-18%) and H' (1.06-0.58) occurred over a 4-mo period.
Fifty-five species of decapod crustaceans are associated with live coral heads of Pocillopora damicornis in the Gulf of Panama. Both numbers of species and individuals of decapods are highly correlated with the area of the coral seads. Small coral heads have fewer species, smaller individual species population sizes and a slightly higher total interspecific density than large coral heads. Area influences species numbers apparently by regulating population sizes of most species. Population sizes of the majority of the species are positively correlated with area, but some are area-independent and one is inversely correlated with area. There are fewer congeneric species than expected on each coral head, possibly because of interspecific interference. knowledge of frequency of occurence allows predictions of species numbers on two small as opposed to one large coral head. Predictions of species numbers on coral heads based on rarefaction are consistently and significantly higher than the observed species numbers.
The present study explored the importance of chemical cues for habitat selection by fish (6 species), crustacean (1 species), and cephalopod (1 species) larvae in a 4-channel choice flume at Ishigaki Island, Japan. The larval attraction toward chemical cues from reef patches (sea-grass bed patch, live coral patch, dead coral patch, and control water; Expt 1) and microhabitats within a given reef patch (live coral colonies, dead coral colonies, seagrass, and conspecifics; Expt 2) was tested in a 4-channel choice flume. The results in Expt 1 showed that 3 fish species used chemical cues to move significantly towards reef patches: Chromis viridis toward live coral patch water and Lutjanus fulviflamma and L. gibbus toward seagrass bed patch water. In Expt 2, 6 of 8 species (4 fishes, 1 cephalopod, and 1 crustacean) used chemical cues to move significantly toward conspecific water (Apogon properuptus, C. viridis, Dascyllus reticulatus, L. fulviflamma, Octopus cyanea, and Palaemonidae sp.). Overall, these results suggest that marine species can actively select settlement habitats according to olfactory cues (more specially, cues from conspecifics). Moreover, these results highlight the importance of conspecific cues over other types of information (reef patch and microhabitat) for habitat selection. Social aggregation of fish, crustacean, and cephalopod larvae with older conspecifics may be the result of individuals using conspecific 'guides' to potentially find beneficial resources (availability of resources and low mortality).
Coral-symbiotic crabs of the genus Tetralia were found to be host specific, discriminating between species of Acropora. Host use was found to significantly differ from host availability in the community, suggesting some degree of specialization between congeners. Intraspecific differences in host utilization were also observed between color morphs of T. nigrolineata, with dark morphs using A. gemmifera more frequently and light morphs using A. tenuis. The distributions of Tetralia species were influenced by wave exposure and depth, with T. rubridactyla and dark morphs of T. nigrolineata almost exclusively found in exposed, shallow habitats. The abundances of T. rubridactyla and T. nigrolineata (both dark and light morphs) generally appear to be correlated with the abundances of their most frequently used host corals, particularly between depths.
Coral reef cryptofauna are a diverse group of metazoan taxa that live within intra- and inter-skeletal voids formed by framework structures. Despite a hypothesized high biomass and numerous trophic roles, they remain uncharacterized relative to exposed reef communities. Motile cryptofauna were sampled from live coral colonies and dead frameworks typifying four successive levels of degradation on an eastern Pacific pocilloporid reef. Abundances and biomass were higher on live versus dead corals habitats. The density of cryptofauna per volume substrate was highest on dead coral frameworks of intermediate degradation, where complex eroded substrates provide abundant shelters. These data have important and far-reaching ramifications for how the diverse multispecies assemblages that are reef ecosystems will respond to anthropogenic stressors such as those associated with climate change. Extreme levels of coral mortality, bioerosion, and habitat destruction will lead to impairment and eventually loss of ecosystem functions.
Nonhierarchial sequences of interference competitive abilities, competitive networks, have been observed in Jamaican cryptic coral reef environments and also appear to exist in Jamaican open reef surface environments. These competitive networks are both numerous and complex; they appear more likely to be formed by interactions between than within major taxonomic groups. The exact spatial position an organism occupies and the rate at which organisms overgrow one another will be important determinants of patterns of species distribution on substrata supporting competitive networks. This will not be the case if a competitive hierarchy exists. The existence of a competitive network on a particular substratum will serve to increase the length of time required for single species resource monopolization relative to the time which would be required if a competitive hierarchy exists, assuming equivalent rates of overgrowth in both cases. The competitive networks situation provides a mechanism for the development o...
A major determinant in reef restoration programs is the choice of species employed. In this paper, we concentrate on the potential use of Montipora digitata (Dana, 1846), a highly fragmented and weedy coral species, for reef restoration and for recreation of reef physiognomy in Bolinao, The Philippines, under the ‘gardening concept’. Coral ramets (n=1960) were reared in a shallow lagoon nursery for 1 year and then, the resulting nursery-grown colonies were transplanted onto denuded reef knolls at two different sites and according to three transplantation designs (grid design with high or low density and patch design). The nursery grown ramets, which had initially exhibited a 99% survivorship, were reduced to 87% by a super typhoon. Low detachment rates, low mortality (
Voucher specimens in a broad sense are redefined as all biological specimens having the minimum information of collection locality (ideally specified by latitude, longitude, altitude) and date that are preserved to document biological research, including taxonomic research. The importance of keeping voucher specimens, and, conversely, the consequences of not so doing, are reviewed briefly. The roles of both systematists and non-systematists in cooperating to ensure that vouchers are properly preserved is emphasized. Practical guidelines, with supporting rationale, are given for non-taxonomists on how to preserve members of the major animal phyla—arthropods, molluscs, and helminths, for taxonomic study and as vouchers.
Coral nurseries solve many of the technical and ecological problems that hamper long-term mass-farming of coral colonies, amenable for active reef restoration. Several types of nurseries have already been developed and tested. We outline here the operational summary of four mid-water, floating nursery prototypes in the Gulf of Eilat, Red Sea, that have been active for up to five years, yielding tens of thousands of healthy and large coral colonies from a number of coral species, a testimony to the long-term sustainability of these coral nurseries. Coral nurseries are similar to agriculture operations in that they require substantial investment of labor. Maintenance included routine checkups on the stability of the construction, the strength of the anchors and ropes and the constant adjustability of nursery's buoyancy. However, a well-designed nursery needs little alteration. Above outcomes relied on the availability of large numbers of coral fragments and nubbins produced at low cost, by low-tech, in the shortest possible culturing periods. The long-term maintenance of mid-water coral nurseries takes into account environmental and physical factors, the kind of coral species reared, ecological parameters and the nursery-specific "mini ecosystem" processes that delineate biological attributes for each mid-water nursery type. While covering a wide range of reef restoration needs, cumulatively, the coral nurseries manifested unique characteristics in comparison to terrestrial nurseries. One hallmark of a mid-water coral nursery is its integration into a de novo evolved floating reef ecosystem, ‘oases’ in blue waters, characteristic by a continuous influx of pests but also valuable reef organisms; this can also significantly improve performance and reduce maintenance costs. In contrast, terrestrial nurseries are designed as isolated and sterile entities. Floating coral nurseries also support practices and ecological services never seen in terrestrial nurseries. The nursery may serve as a hub for growing planula larvae from farmed corals, as a larval source production for other reef-dwelling organisms and as a reef management instrument that evolves into a rich floating ecosystem. Floating nurseries that become the focus of larval attraction from plankton can be used as a unique tool for enhancing connectivity between separated reef sites. Indeed, chains of nurseries can act as ‘stepping stone’ elements in regional reef complex planning. Nurseries situated away from anthropogenic impacts may also serve as mini MPAs, capturing drifted larvae of reef organisms from the plankton, enhancing development of communities that would otherwise lost when migrating to degraded reefs. The original perception of coral nurseries as a solely reef restoration instrument, the production of coral colonies for transplantation, can now be enlarged to include the above-mentioned management tools, developing a multiple-purpose restoration instrument. More study should be devoted to further developing this novel discipline of floating nurseries.