Coral Reef Fish Ecology Research Papers (original) (raw)

Recifes rasos são comumente submetidos à pressões antrópicas, devido à fácil acessibilidade. O objetivo deste estudo foi comparar a diversidade, a estrutura da comunidade e a organização trófica em três setores de recifes de corais em... more

Recifes rasos são comumente submetidos à pressões antrópicas, devido à fácil acessibilidade. O objetivo deste estudo foi comparar a diversidade, a estrutura da comunidade e a organização trófica em três setores de recifes de corais em Barra de Tabatinga, Nísia Floresta, Rio Grande do Norte entre dezembro de 2011 e março de 2012. Além disso, verificou-se a influência de variáveis ambientais
sobre aqueles parâmetros utilizando métodos de censo visual. Foram encontrados 47 espécies de peixes associados aos recifes. A maioria das espécies consumiu invertebrados, padrão já observado para o Nordeste do Brasil. O índice de Shannon
do Setor 1 foi diferente dos demais, o que pode estar relacionado ao grau de conectividade durante a maré seca e a proximidade com um manguezal. Por fim, não houve diferenças significativas entre as comunidades de peixes dos setores, o que sugere que a área parece ser uma única unidade. Contudo, pequenas diferenças na composição e abundância de peixes nos setores elevam a diversidade do local. Dessa forma, todos os setores contribuem para a manutenção e a conservação da área. Estes resultados podem ser úteis para futuros estudos de zoneamento e monitoramento.

Colour polymorphism is widespread in animals but, in contrast to other types of poly- morphism, has been little explored during ontogeny. Among coral reef fish, the surge damselfish Chrysiptera leucopoma settles in the larval stage as a... more

Colour polymorphism is widespread in animals but, in contrast to other types of poly- morphism, has been little explored during ontogeny. Among coral reef fish, the surge damselfish Chrysiptera leucopoma settles in the larval stage as a yellow morph, whereas 2 colour morphs (yellow and brown) are apparent in adults at Rangiroa Atoll, French Polynesia. To understand this dimorphism, we tested, under controlled conditions, the hypotheses that: (1) environmental cues (habitat background and conspecific density) play important roles in morph differentiation during ontogeny and (2) morph colouration is reversible. Our first experiment showed that a dark habitat background induced the formation of the brown morph, while C. leucopoma larvae kept their yellow morph when placed in aquaria with a bright habitat background. Colour change from yellow to brown also occurred within the bright habitat, but only at high conspecific densities. Our second experiment showed that colour change was reversible within 15 d post-settlement, but not at the adult stage. Overall, our results highlighted that the studied polymorphism may be environmentally induced and reversible during the first post-settlement days of this coral reef fish.

Browsing fishes have been identified as an important component of coral reef resilience, because in contrast to other herbivorous fishes they are able to feed on established macroalgae. Climate change and local anthropogenic impacts have... more

Browsing fishes have been identified as an important component of coral reef resilience, because in contrast to other herbivorous fishes they are able to feed on established macroalgae. Climate change and local anthropogenic impacts have contributed to phase shifts in many coral reefs from coral to macroalgae dominance, and recent research suggests the potential ability of browsers to reverse such phase shifts. However, there is high variation among studies and some contradicting findings exist. Here, we review the relevant literature to assemble a list of species currently known to contribute to browsing in the Indo-Pacific. Furthermore, we identify spatial and temporal patterns, outline factors influencing browsing, and discuss the probability of phase shift reversal. We formulate research recommendations addressing the identified gaps in knowledge about the interactions of browsing fishes and their environment. To date, 37 species of fishes have been observed consuming macroalgae in the Indo-Pacific. The most important groups are the family Siganidae, the subfamily Scarinae (Labridae), and the subfamily Nasinae (Acanthuridae). Browsing species vary between studies depending on location, season and macroalgae species examined. Several influencing factors, such as structural complexity, palatability of macroalgae and ecosystem connectivity have been suggested to cause these discrepancies. The most promising avenues for future research are the effect of structural complexity, the importance of mobile link species and influences of food availability on the selectivity of browsing species. Increasing our knowledge in these fields will provide a better basis for successful management strategies directed at increasing the resilience of coral reefs.

Fish assemblages on four large (100 m 2) artificial reefs were censused in May, June and July, 1986 and again in May 1988. The mean coefficient of variation of species' relative density decreased from 1986 to 1988, while the mean percent... more

Fish assemblages on four large (100 m 2) artificial reefs were censused in May, June and July, 1986 and again in May 1988. The mean coefficient of variation of species' relative density decreased from 1986 to 1988, while the mean percent similarity of fish assemblages increased from 1986 to 1988. Fish assemblages on two of the large artificial reefs and on equal areas of the nearest natural coral reef were censused biweekly for 12 mo. Neither reef type (artificial or natural) nor reef location appeared to have an effect on assemblage structure. Fish assemblages on six small (1 m 2) concrete block reefs were censused biweekly for 12 mo; three of the six reefs were denuded at 3-mo intervals. Assemblages on these small reefs were less predictable than those on the large artificial and natural reefs. Predictability of fish assemblages on large and small reefs generally increased with number of species present, but was not consistently related to total number of individuals present. Values of assemblage similarity varied from agreement with Australian studies, which generally espouse recruitment-limited, non-equilibrial assemblage structure, to agreement with other Caribbean studies, which generally espouse stable, resource-limited assemblage structure. It is concluded that the dichotomy of results between Australian and Caribbean studies of reef fish assemblage structure is primarily a result of different sampling methodology and analysis coupled with different species pools, and requires no difference in biological mechanism.

The relationships of reef fish abundance, trophic composition, and diversity with reef habitats were investigated at Vaan Island, which lies in the southern tip of Gulf of Mannar Marine National Park. Underwater data on reef fish... more

The relationships of reef fish abundance, trophic composition, and diversity with reef habitats were investigated
at Vaan Island, which lies in the southern tip of Gulf of Mannar Marine National Park. Underwater data on reef fish
abundance and diversity were collected by following belt transect method involving scuba diving at three reef habitats
namely inshore reef, reef flat and reef edge during the study period between November and December 2016. A total of
48 species from 31 genera belonging to 19 families were recorded. Among the three reef habitats, the highest abundance
and diversity of fishes were recorded in the reef edge area. The trophic groups in these three reef sites were dominated
by carnivores (26.32%), but herbivores and feeders on sessile invertebrates were relatively lower in abundance. There
was a significant variation in fish abundance among the reef habitats. These findings revealed that the complexity of
reef structure determines the abundance and diversity of reef fishes in Vaan Island.

Mesophotic coral ecosystems (MCEs) support diverse communities of marine organisms with changes in community structure occurring along a depth gradient. In recent years, MCEs have gained attention due to their depths that provide... more

Mesophotic coral ecosystems (MCEs) support diverse communities of marine organisms with changes in community structure occurring along a depth gradient. In recent years, MCEs have gained attention due to their depths that provide protection from natural and anthropogenic stressors and their relative stability over evolutionary time periods, yet ecological structures of fish assemblages in MCEs remain largely undocumented. Here, we investigated composition and trophic structure of reef fish assemblages in the Northwestern Hawaiian Islands (NWHI) along a depth gradient from 1 to 67 m. The structure of reef fish assemblages as a whole showed a clear gradient from shallow to mesophotic depths. Fish assemblages at mesophotic depths had higher total densities than those in shallower waters, and were characterized by relatively high densities of planktivores and invertivores and relatively low densities of herbivores. Fishes that typified assemblages at mesophotic depths included six species that are endemic to the Hawaiian Islands. The present study showed that mesophotic reefs in the NWHI support unique assemblages of fish that are characterized by high endemism and relatively high densities of planktivores. Our findings underscore the ecological importance of these undersurveyed ecosystems and warrant further studies of MCEs.

Transient fish spawning aggregations (tFSas) are critical life-history phenomena where fish migrate to specific locations at predictable times of year to reproduce en masse. In the wider Caribbean region, 37 species of fish from 10... more

Transient fish spawning aggregations (tFSas) are critical life-history phenomena where fish migrate to specific locations at predictable times of year to reproduce en masse. In the wider Caribbean region, 37 species of fish from 10 families are now known to form tFSas. although tFSas likely occur at times and in places that maximize reproductive success, little is known about the complex suite of interacting environmental patterns and ecological processes that dictate the timing and locations of tFSas. This review synthesizes the latest advances in the study of tFSas in the wider Caribbean to (1) illustrate the current state of knowledge; (2) highlight gaps in our understanding of the geography and ecology of aggregation sites; and (3) suggest future research needs and conservation strategies. we have compiled multidisciplinary data on 108 tFSas across 14 states and territories in the wider Caribbean and reviewed the full range of approaches and technologies applied to study tFSas. Existing research and associated hypotheses are grouped and examined by data type. we propose a multitier research framework that provides an incremental approach to information gathering at individual sites and suites of sites. we advocate applying the framework to facilitate consistent and coordinated data collection and monitoring across a wider Caribbean network of tFSas.

Numerous studies have explored the ‘shifting baseline syndrome’ (SBS) which suggests that individual perceptions of environmental health are formed by comparing the environment to a ‘baseline’ from the past. Understanding social... more

Numerous studies have explored the ‘shifting baseline syndrome’ (SBS) which suggests that individual perceptions of environmental health are formed by comparing the environment to a ‘baseline’ from the past. Understanding social perceptions of environmental conditions, especially where they differ from ecological assessments, can help guide environmental management efforts. This study compares ecological assessments of coral reef health with perceptions of reef health from surveyed residents in five villages in the Solomon Islands and Fiji. Comparative analysis suggests that respondents from the Solomon Islands perceived their reefs as being degraded, yet based on ecological measurements actually had healthier reefs, while in Fiji fewer people perceived their reefs to be declining in health yet ecological
measurement showed them to be more degraded than Solomon Islands reefs. We found no evidence of baselines “shifting” relative to respondent age in this instance and suggest that these differential baselines and the inverse relationship between local perceptions and ecological measurements may be a result of: (1) differences in the rate of environmental change experienced at local scales; and (2) may also be related to differences in respondent perceptions of ‘quality of life’ at each site. If the success of conservation approaches such as marine protected areas (MPAs) are dependent on local social consensus that natural resources are diminished or degraded, then tracking broader social indicators like ‘quality of life’, ‘rates of change’ (real and perceived) alongside ecological assessments of environmental health may prove beneficial to conservation practitioners.

Bluespine unicornfish (Naso unicornis) from Hawaii were aged to >50 years using cross-sectioned sagittal otoliths. Fish length was a poor indicator of age because of rapid and variable early growth, exemplified by fish aged to be 4 years... more

Bluespine unicornfish (Naso unicornis) from Hawaii were aged to >50 years using cross-sectioned sagittal otoliths. Fish length was a poor indicator of age because of rapid and variable early growth, exemplified by fish aged to be 4 years near maximum length. Growth was deterministic with adult ages decoupled from body length. Otolith mass and thickness were evaluated as proxies for age and both were encouraging; thickness explained more variance but mass was easier to measure. An age estimation protocol was validated through ontogeny using bomb radiocarbon (14 C) dating. Use of the postbomb 14 C decline period from a regional reference chronology enabled age validation of young fish — a novel approach for the Pacific Ocean. A probabilistic procedure for assigning bomb 14 C dates (CALIBomb) was used for the first time to determine fish birth years. The age-reading protocol was generally validated, and it was possible to describe length-at-age despite difficulties in counting otolith annuli beyond 30–40 years. Growth curves differed between the sexes, and a four-parameter generalized von Bertalanffy growth function provided the best fit.

In March-April 2000, a survey applying the Atlantic and Gulf Rapid Reef Assessment benthos protocol was accomplished in the Abrolhos National Marine Park. The Santa Bárbara Island fringing reef and offshore "chapeirões" (isolated columnar... more

In March-April 2000, a survey applying the Atlantic and Gulf Rapid Reef Assessment benthos protocol was accomplished in the Abrolhos National Marine Park. The Santa Bárbara Island fringing reef and offshore "chapeirões" (isolated columnar reefs) were assessed to evaluate their present status and provide standards for future monitoring programs. The chapeirões were rated as well preserved in terms of the density and health of large (≥25 cm in diameter) stony corals, the density of stony coral recruits, and the scarcity of benthic macroalgae. However, concerns were raised about the fringing reef, particularly off the island's southern coast. Although the causes for its poor condition here are not well understood, the intrinsic oceanographic setting, in particular exposure to storm waves in winter, and the presence of numerous tourist divers and snorkelers during the summer must be investigated.

Understanding resource stakeholders' perceptions of resource condition and management is vital to the formulation of efficacious management policy to sustain natural systems because agreement among stakeholders is likely to result in more... more

Understanding resource stakeholders' perceptions of resource condition and management is vital to the formulation of efficacious management policy to sustain natural systems because agreement among stakeholders is likely to result in more effective outcomes. Understanding perceptions is particularly important in the context of coral reefs because threats are often diverse and management options are numerous, and therefore perceptions are likely to be diverse. This study identified the dominant discourses of reef fish decline, and increase, among 119 fishers and fish traders (herein middlemen) in Solomon Islands, and compared these discourses to current scientific knowledge. Discourses were then explored for dominant themes that might improve understanding of resource user perceptions. The findings suggest that certain fisher and middlemen discourses align with scientific understanding of the causal links between human activity and fish stock declines, and that many of the elicited management strategies are aligned with current scientific recommendations. A theme that emerged across the fisher and middlemen discourses of fish decline was a dichotomy in perception between fishing for economic affluence and fishing for subsistence and economic survival. A theme that emerged across discourses of fish increase was a dichotomy between support for command-and-control approaches and support for community-based approaches to management. Differences between some fisher and middlemen discourses were explained by the location in which interviews were conducted suggesting consensual perceptions achieved through local knowledge networks. Similarity between scientific understanding and local perceptions suggests that local resource users are aware of, and might support, fishery management strategies based on scientific evidence. Such strategies must consider factors such as location because resource user perceptions differ between locations and because many threats to the fishery and preferred management strategies are likely to be context specific.

Abstract: Numerous studies have explored the “shifting baseline syndrome” (SBS), which suggests that individual perceptions of environmental health are formed by comparing the environment to a “baseline” from the past. Understanding... more

Abstract: Numerous studies have explored the “shifting baseline syndrome” (SBS), which suggests that individual perceptions of environmental health are formed by comparing the environment to a “baseline” from the past. Understanding social perceptions of environmental conditions, especially where they differ from ecological assessments, can help guide environmental management efforts. In this study we compared ecological assessments of coral reef health with perceptions of reef health from surveyed residents in five villages in Solomon Islands and Fiji. Comparative analysis suggests that respondents from Solomon Islands perceived their reefs as being degraded, yet based on ecological measurements actually had healthier reefs, while in Fiji fewer people perceived their reefs to be declining in health, yet ecological measurement showed them to be more degraded than Solomon Islands reefs. We found no evidence of baselines “shifting” relative to respondent age in this instance and suggest that these differential baselines and the inverse relationship between local perceptions and ecological measurements may be a result of: (1) differences in the rate of environmental change experienced at local scales; and (2) may also be related to differences in respondent perceptions of “quality of life” at each site. If the success of conservation approaches such as marine protected areas (MPAs) are dependent on local social consensus that natural resources are diminished or degraded, then tracking broader social indicators like “quality of life” and “rates of change” (real and perceived) alongside ecological assessments of environmental health may prove beneficial to conservation practitioners.

Many marine reef fishes have pelagic larval stages that develop in offshore waters. These larvae face the great challenge of relocating to patchily distributed reef environments in a vast oceanic matrix. We explored how chemical cues... more

Many marine reef fishes have pelagic larval stages that develop in offshore waters. These larvae face the great challenge of relocating to patchily distributed reef environments in a vast oceanic matrix. We explored how chemical cues emitted from coral versus algal reefs attract fish larvae at Rangiroa Atoll (French Polynesia). Experiments with 2-channel choice chambers showed that during the recruitment stage, 7 of the 10 fish species studied preferred water from reefs dominated by coral compared to reefs dominated by algae (e.g. Aulostomus chinensis, Chromis viridis, Ptereleotris microlepis, and Sargocentron spiniferum). Only Zebrasoma veliferum preferred water from reefs dominated by algae. Overall, olfactory cues could play an important role in directing pelagic larval stage fishes to a suitable reef on which they can settle.

In March-April 2000, a survey applying the Atlantic and Gulf Rapid Reef Assessment benthos protocol was accomplished in the Abrolhos National Marine Park. The Santa Bárbara Island fringing reef and offshore "chapeirões" (isolated columnar... more

In March-April 2000, a survey applying the Atlantic and Gulf Rapid Reef Assessment benthos protocol was accomplished in the Abrolhos National Marine Park. The Santa Bárbara Island fringing reef and offshore "chapeirões" (isolated columnar reefs) were assessed to evaluate their present status and provide standards for future monitoring programs. The chapeirões were rated as well preserved in terms of the density and health of large (≥25 cm in diameter) stony corals, the density of stony coral recruits, and the scarcity of benthic macroalgae. However, concerns were raised about the fringing reef, particularly off the island's southern coast. Although the causes for its poor condition here are not well understood, the intrinsic oceanographic setting, in particular exposure to storm waves in winter, and the presence of numerous tourist divers and snorkelers during the summer must be investigated.

' habitat utilization patterns among management regimes, we deployed an array of hydroacoustic receivers and acoustically tagged reef fishes. Thirty six receivers were deployed in shallow near-shore bays and across the shelf to depths of... more

' habitat utilization patterns among management regimes, we deployed an array of hydroacoustic receivers and acoustically tagged reef fishes. Thirty six receivers were deployed in shallow near-shore bays and across the shelf to depths of approximately 30 m. One hundred eighty four individual fishes were tagged representing 19 species from 10 different families with VEMCO V9-2L-R64K transmitters. The array provides fish movement information at fine (e.g., day-night and 100s meters within a bay) to broad spatial and temporal scales (multiple years and 1000s meters across the shelf). The long term multi-year tracking project provides direct evidence of connectivity across habitat types in the seascape and among management units. An important finding for management was that a number of individuals moved among management units (VICRNM, VINP, Territorial waters) and several snapper moved from near-shore protected areas to offshore shelf-edge spawning aggregations. However, most individuals spent the majority of their time with VIIS and VICRNM, with only a few wide-ranging species moving outside the management units. Five species of snappers (Lutjanidae) accounted for 31% of all individuals tagged, followed by three species of grunts (Haemulidae) accounting for an additional 23% of the total. No other family had more than a single species represented in the study. Bluestripe grunt (Haemulon sciurus) comprised 22% of all individuals tagged, followed by lane snappers (Lutjanus synagris) at 21%, bar jack (Carangoides ruber) at 11%, and saucereye porgy (Calamus calamus) at 10%. The largest individual tagged was a 70 cm TL nurse shark (Ginglymostoma cirratum), followed by a 65 cm mutton snapper (Lutjanus analis), a 47 cm bar jack, and a 41 cm dog snapper (Lutjanus jocu). The smallest individuals tagged were a 19 cm blue tang (Acanthurus coeruleus) and a 19.2 cm doctorfish (Acanthurus chirurgus). Of the 40 bluestriped grunt acoustically tagged, 73% were detected on the receiver array. The average days at large (DAL) was 249 (just over 8 months), with one individual detected for 930 days (over two and a half years). Lane snapper were the next most abundant species tagged (N = 38) with 89% detected on the array. The average days at large (DAL) was 221 with one individual detected for 351 days. Seventy-one percent of the bar jacks (N = 21) were detected on the array with the average DALs at 47 days. All of the mutton snapper (N = 12) were detected on the array with an average DAL of 273 and the longest at 784. The average maximum distance travelled (MDT) was ca. 2 km with large variations among species. Grunts, snappers, jacks, and porgies showed the greatest movements. Among all individuals across species, there was a positive and significant correlation between size of individuals and MDT and between DAL and MDT. Overall, for all species pooled, 71% of the time was spent in VIIS, 25% in VICRNM, and only 4% in territorial waters. Based on these data and species' life history requirements, the current management boundaries appear adequate for most species, except for the most wide-ranging and transient ones. Many of the points along the south shore of St. John are hotspots for tagged fish detections and are likely used as movement reference points along migratory pathways. The patch reefs at White Cliffs appear to be an important transit point for fishes moving between the near-shore areas of VIIS and the deeper mid-shelf reef in VICRNM. Acoustic telemetry of reef fishes has proven to be a valuable tool for examining long-term movement patterns of fishes around St. John. This cost effective approach has identified important corridors that connect habitats and management units along the south shore of St. John. It also highlights the variability among species and the importance of taking an ecosystem-based approach to ecology studies.

Transient fish spawning aggregations (tFSas) are critical life-history phenomena where fish migrate to specific locations at predictable times of year to reproduce en masse. In the wider Caribbean region, 37 species of fish from 10... more

Transient fish spawning aggregations (tFSas) are critical life-history phenomena where fish migrate to specific locations at predictable times of year to reproduce en masse. In the wider Caribbean region, 37 species of fish from 10 families are now known to form tFSas. although tFSas likely occur at times and in places that maximize reproductive success, little is known about the complex suite of interacting environmental patterns and ecological processes that dictate the timing and locations of tFSas. This review synthesizes the latest advances in the study of tFSas in the wider Caribbean to (1) illustrate the current state of knowledge; (2) highlight gaps in our understand-ing of the geography and ecology of aggregation sites; and (3) suggest future research needs and conservation strategies. we have compiled multidisciplinary data on 108 tFSas across 14 states and territories in the wider Caribbean and reviewed the full range of approaches and technologies applied to study tFSas....

Recruitment and population density of coral reef fishes were studied on artificial and natural reefs on the west coast of Barbados. Recruitment of all species combined and of 3 common species (Thalassoma bifasciatum, Stegastes partitus... more

Recruitment and population density of coral reef fishes were studied on artificial and natural reefs on the west coast of Barbados. Recruitment of all species combined and of 3 common species (Thalassoma bifasciatum, Stegastes partitus and Halichoeres garnoti) occurred mostly from May to November. Recruitment rate varied little across reef types and reef locations. Population density of all species combined and of the 3 common species varied little throughout the year, but did vary across reefs and locations. The observation that patterns of seasonal and spatial variation in densities did not reflect the patterns of seasonal and spat~al variation in recruitment suggests that reef fish populations in Barbados may be primarily regulated by post-settlement events. Recruitment of all species combined and of the 3 common species was not affected by the density of all species combined. No evidence could be found for interspecific competition, i.e. a negat~ve relat~onship between the density of one species and the recruitment of another. However, recrultrnent of H garnoti was inhibited on some reefs by high dens~ties of conspecifics. Post-recruitment mortality of all species combined was not affected by denslty of all species. However, post-recruitment mortality of T bifasciatum and S. partitus was higher on reefs of hlgher conspecific density. These results provide ev~dence for the regulation of reef fish pop-ulat~ons In Barbados by post-settlement processes, and suggest that intraspecific interactions may be particularly important in limiting population size.

Colour polymorphism is widespread in animals but, in contrast to other types of polymorphism, has been little explored during ontogeny. Among coral reef fish, the surge damselfish Chrysiptera leucopoma settles in the larval stage as a... more

Colour polymorphism is widespread in animals but, in contrast to other types of polymorphism, has been little explored during ontogeny. Among coral reef fish, the surge damselfish Chrysiptera leucopoma settles in the larval stage as a yellow morph, whereas 2 colour morphs (yellow and brown) are apparent in adults at Rangiroa Atoll, French Polynesia. To understand this dimorphism, we tested, under controlled conditions, the hypotheses that: (1) environmental cues (habitat background and conspecific density) play important roles in morph differentiation during ontogeny and (2) morph colouration is reversible. Our first experiment showed that a dark habitat background induced the formation of the brown morph, while C. leucopoma larvae kept their yellow morph when placed in aquaria with a bright habitat background. Colour change from yellow to brown also occurred within the bright habitat, but only at high conspecific densities. Our second experiment showed that colour change was reversible within 15 d post-settlement, but not at the adult stage. Overall, our results highlighted that the studied polymorphism may be environmentally induced and reversible during the first post-settlement days of this coral reef fish.

Underwater Visual Census (UVC) and Baited Remote Underwater Video (BRUV) are broadly used methods to study fish assemblages in marine and estuarine environments. This study compared the results of BRUV and UVC methods for assessing... more

Underwater Visual Census (UVC) and Baited Remote Underwater Video (BRUV) are broadly used methods to study fish assemblages in marine and estuarine environments. This study compared the results of BRUV and UVC methods for assessing seasonal trends in coral reef fish assemblages in a marginal reef in the northern Persian Gulf. In doing so, seasonal surveys of coral reef fishes were done using BRUV and UVC methods. Comparison of assemblage metrics driven from each method indicated that both methods may reveal similar patterns of seasonal changes in fish and trophic group assemblages while there may be between-method differences in species richness, total abundance, and trophic group abundances. The observed differences may be related to the longer sampling times of BRUV.

Predation is a key ecosystem function, especially in high diversity systems such as coral reefs. Not only is predation one of the strongest top-down controls of prey population density, but it also is a strong driver of prey behaviour and... more

Predation is a key ecosystem function, especially in high diversity systems such as coral reefs. Not only is predation one of the strongest top-down controls of prey population density, but it also is a strong driver of prey behaviour and function through non-lethal effects. We ask whether predation risk influences sheltering behaviour of damselfish living in mutualism with branching corals. Host corals gain multiple advantages from the mutualistic relationship which are determined by the strength of damselfish sheltering. Distance travelled by the Lemon Damselfish Pomacentrus moluccensis away from their host colony was measured here as a proxy for sheltering strength and was expected to be shortest under highest predation risk. Predation risk, defined as a function of predator abundance and activity, turbidity and habitat complexity, was quantified at four reef slope sites in Kepulauan Seribu, Indonesia. Damselfish sheltering strength was measured using stationary unmanned video ca...

NOAA’s National Centers for Coastal Ocean Science (NCCOS)-Center for Coastal Monitoring and Assessment’s (CCMA) Biogeography Branch, National Park Service (NPS), US Geological Survey, and the University of Hawaii used acoustic telemetry... more

NOAA’s National Centers for Coastal Ocean Science (NCCOS)-Center for Coastal Monitoring and Assessment’s (CCMA) Biogeography Branch, National Park Service (NPS), US Geological Survey, and the University of Hawaii used acoustic telemetry to quantify spatial patterns and habitat affinities of reef fishes around the island of St. John, US Virgin Islands. The objective of the study was to define the movements of reef fishes among habitats within and between the Virgin Islands Coral Reef National Monument (VICRNM), the Virgin Islands National Park (VIIS), and Territorial waters surrounding St. John. In order to better understand species’ habitat utilization patterns among management regimes, we deployed an array of hydroacoustic receivers and acoustically tagged reef fishes. Thirty six receivers were deployed in shallow near-shore bays and across the shelf to depths of approximately 30 m. One hundred eighty four individual fishes were tagged representing 19 species from 10 different fami...

Predation is a key ecosystem function, especially in high diversity systems such as coral reefs. Not only is predation one of the strongest top-down controls of prey population density, but it also is a strong driver of prey behaviour and... more

Predation is a key ecosystem function, especially in high diversity systems such as coral reefs. Not only is predation one of the strongest top-down controls of prey population density, but it also is a strong driver of prey behaviour and function through non-lethal effects. We ask whether predation risk influences sheltering behaviour of damselfish living in mutualism with branching corals. Host corals gain multiple advantages from the mutualistic relationship which are determined by the strength of damselfish sheltering. Distance travelled by the Lemon Damselfish Pomacentrus moluccensis away from their host colony was measured here as a proxy for sheltering strength and was expected to be shortest under highest predation risk. Predation risk, defined as a function of predator abundance and activity, turbidity and habitat complexity, was quantified at four reef slope sites in Kepulauan Seribu, Indonesia. Damselfish sheltering strength was measured using stationary unmanned video cameras. Small damselfish (< 2 cm) increased their sheltering strength under high turbidity. Predator feeding activity , but not abundance, influenced damselfish sheltering strength. Contrary to our expectations, sheltering behaviour of adult damselfish decreased under high predator activity. While these observations are in line with risk-averse behaviour by juvenile P. moluccensis, they may indicate the presence of sentinel behaviour in the adults of this species. Habitat complexity seemed to be less important as a driver of damselfish behaviour. These counterin-tuitive results may indicate complex social behaviour and age-specific strategies for predator avoidance.

In March-April 2000, a survey applying the Atlantic and Gulf Rapid Reef Assessment benthos protocol was accomplished in the Abrolhos National Marine Park. The Santa Bárbara Island fringing reef and offshore "chapeirões" (isolated columnar... more

In March-April 2000, a survey applying the Atlantic and Gulf Rapid Reef Assessment benthos protocol was accomplished in the Abrolhos National Marine Park. The Santa Bárbara Island fringing reef and offshore "chapeirões" (isolated columnar reefs) were assessed to evaluate their present status and provide standards for future monitoring programs. The chapeirões were rated as well preserved in terms of the density and health of large (≥25 cm in diameter) stony corals, the density of stony coral recruits, and the scarcity of benthic macroalgae. However, concerns were raised about the fringing reef, particularly off the island's southern coast. Although the causes for its poor condition here are not well understood, the intrinsic oceanographic setting, in particular exposure to storm waves in winter, and the presence of numerous tourist divers and snorkelers during the summer must be investigated.

Colour polymorphism is widespread in animals but, in contrast to other types of polymorphism, has been little explored during ontogeny. Among coral reef fish, the surge damselfish Chrysiptera leucopoma settles in the larval stage as a... more

Colour polymorphism is widespread in animals but, in contrast to other types of polymorphism, has been little explored during ontogeny. Among coral reef fish, the surge damselfish Chrysiptera leucopoma settles in the larval stage as a yellow morph, whereas 2 colour morphs (yellow and brown) are apparent in adults at Rangiroa Atoll, French Polynesia. To understand this dimorphism, we tested, under controlled conditions, the hypotheses that: (1) environmental cues (habitat background and conspecific density) play important roles in morph differentiation during ontogeny and (2) morph colouration is reversible. Our first experiment showed that a dark habitat background induced the formation of the brown morph, while C. leucopoma larvae kept their yellow morph when placed in aquaria with a bright habitat background. Colour change from yellow to brown also occurred within the bright habitat, but only at high conspecific densities. Our second experiment showed that colour change was reversible within 15 d post-settlement, but not at the adult stage. Overall, our results highlighted that the studied polymorphism may be environmentally induced and reversible during the first post-settlement days of this coral reef fish.

The present study was conducted on Tamandaré reefs, northeast Brazil and aimed to analyse the importance of different factors (e.g. tourism activity, fishing activity, coral abundance and algal abundance) on reef fish abundance and... more

The present study was conducted on Tamandaré reefs, northeast Brazil and aimed to analyse the importance of different factors (e.g. tourism activity, fishing activity, coral abundance and algal abundance) on reef fish abundance and species richness. Two distinct reef areas (A ver o mar and Caieiras) with different levels of influence were studied. A total of 8239 reef fish individuals were registered, including 59 species. Site 1 (A ver o mar) presented higher reef fish abundance and richness, with dominance of roving herbivores (29.9 %) and mobile invertebrate feeders (28.7 %). In contrast, at Site 2 (Caieiras) territorial herbivores (40.9 %) predominated, followed by mobile invertebrate feeders (24.6 %). Concerning the benthic community, at Site 1 macroalgae were recorded as the main category (49.3 %); however, Site 2 was dominated by calcareous algae (36.0 %). The most important variable explaining more than 90 % of variance on reef fish abundance and species richness was macroalgae abundance, followed by fishing activity. Phase shifts on coral reefs are evident, resulting in the replacement of coral by macroalgae and greatly influencing reef fish communities. In this context, it is important to understand the burden of the factors that affect reef fish communities and, therefore, influence the extinction vulnerability of coral reef fishes.