Reef Fish Community Structure Research Articles

Isolation promotes abundance and species richness of fishes recruiting to coral reef patches

Habitat area and fragmentation are recognised as important factors that influence population size, community structure and extinction risk. Abundance and species richness universally increase with habitat area. However, the effects of different aspects of habitat fragmentation, including variation in patch size, number and isolation are often not distinguished from each other or the overall effects of habitat amount. Here we experimentally tested predictions concerning the effects of isolation on abundance, species richness and community structure of coral reef fishes colonising patch reefs by constructing clusters of patches of the same number and size, but manipulating reef spacing. Hexagonal clusters of 7 experimental patch reefs (6 edge and 1 central) with 3 levels of isolation (1 m, 5 m, and 15 m spacing) were established at Kavieng, Papua New Guinea and colonisation was recorded after 6 weeks in 2014. We also deployed video cameras to test whether isolation affected the activity of transient predatory fishes. As predicted, isolation had a positive effect on both mean abundance and species richness at both the cluster and patch scale. The cumulative abundance and species richness exhibited linear increases in relation to habitat area within clusters (from 1 to 7 patch reefs), but the slope increased with the degree of isolation. There was some evidence that transient predators remained longer and were more successful when patches were close together, which may explain the lower abundance and richness of juvenile fish assemblages on more aggregated patch reefs. This study demonstrates that while habitat amount is fundamentally important, isolation has significant effects that will need to be distinguished from other aspects of fragmentation when examining the processes structuring reef fish communities.

Seascape Configuration and Fine-Scale Habitat Complexity Shape Parrotfish Distribution and Function across a Coral Reef Lagoon

Structural complexity spanning fine to broad spatial scales can influence the distribution and activity of key organisms within marine ecosystems. However, the relative importance of hard (e.g., corals) and/or soft (e.g., macroalgae) structural complexity for marine organisms is often unclear. This study shows how both broad-scale (seascape configuration of coral structure) and fine-scale habitat complexity (structure height, number of holes, and presence of macroalgae) can influence the abundance and spatial ecology of reef fish. Underwater visual census of fish, surveys of habitats, remote underwater videos, and behavioral observations by following individual fish were used to quantify fine-scale habitat characteristics (e.g., complexity, coral structure height, macroalgae presence) and the abundance, size structure, and behavior (rates of herbivory, tortuosity ratios and total distance travelled) of abundant parrotfish. Both seascape configuration and macroalgae influenced the patterns of fish abundance and rates of herbivory. However, these relationships varied with trophic groups and ontogenetic stages. Abundance of adult and intermediate-phase parrotfishes was positively influenced by densely aggregated coral structures, whereas juvenile abundance was positively influenced by the presence of macroalgae. Foraging path and bite rates of an abundant parrotfish, Chlorurus spilurus, were not influenced by coral structure configuration or height, but the presence of macroalgae increased the bite rates of all juvenile parrotfish. Our results suggest that a combination of seascape configuration, fine-scale habitat complexity, and microhabitat selectivity influence reef fish community structure and foraging behavior, thus altering herbivory. However, these relationships can differ among functional groups of fish and life-history stages. Information on these fish–habitat interactions is critical for identifying habitats that facilitate ecological functions and ensures the successful management and conservation of essential habitats.

Trends in recreational fisheries and reef fish community structure indicate decline in target species population in an isolated tropical oceanic island

Marine recreational fisheries and fish communities have been mostly studied separately, severely hampering the detection of possible interactions. Here we monitored recreational fishery landings (angling and spearfishing) and assessed the reef fish community through underwater visual censuses in Trindade, an isolated oceanic island in the southwestern Atlantic Ocean. The study was conducted in zones of high and low fishing effort, along three different years spread over a seven-year period. We found high catch per unit effort (CPUE; kg*fisher−1*hour−1) associated with high fishing intensity. However, the biomass of the targeted species in the natural environment decreased by 58% over time, while fishing effort increased about 270%, and CPUE decreased by 40%. Inverse relationships between effort and CPUE, and effort and biomass in the environment, were stronger in zones of high fishing effort. We conclude that the recreational fishery activity quickly responded to overfishing, creating a harvesting process that negatively impacted reef fish communities in this isolated oceanic island. Thus, conservation strategies should incorporate long-term recreational catch and fish community monitoring programs. Here we discuss options for the sustainability of the recreational fisheries and reinforce the importance of dialogue among scientists, managers and users for the achievement of conservation goals.

Changes in Reef Fish Community Structure Following the Deepwater Horizon Oil Spill

Large-scale anthropogenic disturbances can have direct and indirect effects on marine communities, with direct effects often taking the form of widespread injury or mortality and indirect effects manifesting as changes in food web structure. Here, we report a time series that captures both direct and indirect effects of the Deepwater Horizon Oil Spill (DWH) on northern Gulf of Mexico (nGoM) reef fish communities. We observed significant changes in community structure immediately following the DWH, with a 38% decline in species richness and 26% decline in Shannon-Weiner diversity. Initial shifts were driven by widespread declines across a range of trophic guilds, with subsequent recovery unevenly distributed among guilds and taxa. For example, densities of small demersal invertivores, small demersal browsers, generalist carnivores, and piscivores remained persistently low with little indication of recovery seven years after the DWH. Initial declines among these guilds occurred prior to the arrival of the now-widespread, invasive lionfish (Pterois spp.), but their lack of recovery suggests lionfish predation may be affecting recovery. Factors affecting persistently low densities of generalist carnivores and piscivores are not well understood but warrant further study given the myriad ecosystem services provided by nGoM reef fishes.

Behavioural traits and feeding ecology of Mediterranean lionfish and naiveté of native species to lionfish predation

The detrimental effects of invasion by Indo-Pacific lionfish Pterois volitans/miles on western Atlantic fishes have spurred concerns for Mediterranean fish biodiversity, where Lessepsian lionfish P. miles have recently established populations in the eastern basin. In order to assess the potential impact on biodiversity, we examined key behavioural and ecological traits of lionfish and the resident fish community in the Mediterranean that may contribute to lionfish invasion success. We focussed on Cyprus, where lionfish were first sighted in 2012 and have now formed abundant and stable populations. Using field observations, we examined lionfish predatory behaviour and feeding ecology, and naiveté of resident fish species to hunting lionfish. Our findings suggest that lionfish in the Mediterranean are crepuscular generalist predators, with targeted prey dominated by small-bodied benthic or bentho-pelagic associated species. Such prey are more likely to be native than introduced (Lessepsian) fishes, with native prey fishes showing greater naiveté towards lionfish than Lessepsian prey species. Notably, one of the Mediterranean’s key ecological fish species (the native damselfish Chromis chromis) showed the highest level of naiveté and was the most heavily targeted prey. Overall, lionfish in the Mediterranean show similar predatory behaviour and ecology to their western Atlantic counterparts. Although the establishment of Mediterranean lionfish populations is still recent, it may result in a similar disruption to reef fish biomass to that recorded in the Atlantic, with impacts on the structure and biodiversity of reef fish communities and the services they provide.

Climate-driven shift in coral morphological structure predicts decline of juvenile reef fishes.

Rapid intensification of environmental disturbances has sparked widespread decline and compositional shifts in foundation species in ecosystems worldwide. Now, an emergent challenge is to understand the consequences of shifts and losses in such habitat-forming species for associated communities and ecosystem processes. Recently, consecutive coral bleaching events shifted the morphological makeup of habitat-forming coral assemblages on the Great Barrier Reef (GBR). Considering the disparity of coral morphological growth forms in shelter provision for reef fishes, we investigated how shifts in the morphological structure of coral assemblages affect the abundance of juvenile and adult reef fishes. We used a temporal dataset from shallow reefs in the northern GBR to estimate coral convexity (a fine-scale quantitative morphological trait) and two widely used coral habitat descriptors (coral cover and reef rugosity) for disentangling the effects of coral morphology on reef fish assemblages. Changes in coral convexity, rather than live coral cover or reef rugosity, disproportionately affected juvenile reef fishes when compared to adults, and explained more than 20% of juvenile decline. The magnitude of this effect varied by fish body size with juveniles of small-bodied species showing higher vulnerability to changes in coral morphology. Our findings suggest that continued large-scale shifts in the relative abundance of morphological groups within coral assemblages are likely to affect population replenishment and dynamics of future reef fish communities. The different responses of juvenile and adult fishes according to habitat descriptors indicate that focusing on coarse-scale metrics alone may mask fine-scale ecological responses that are key to understand ecosystem functioning and resilience. Nonetheless, quantifying coral morphological traits may contribute to forecasting the structure of reef fish communities on novel reef ecosystems shaped by climate change.

Community structure of target reef fish at four tiny islands coral reefs in inner Kotania bay, Maluku Province, Indonesia

Study on community structure of target reef fish at four tiny islands coral reefs in inner Kotania bay was conducted from September 2017 to February 2018. Underwater Visual Census method was used to collect and examine data concerning several parameters of target reef fish community structure. At least 18 families of target reef fish which consist of 37 genera and 105 species were found during the study. Good and excellent categories of coral reefs condition had higher species richness and individual abundance of target reef fish, while lower in fair category. Seven target reef fish species have a wide distribution, while other 15 species were limited. In general, target reef fish community at four tiny islands coral reefs had high species diversity and evenness indexes with low species dominance value. It can be concluded that target reef fish community in the area in stable or in steady state condition.

Influence of habitat condition on shallow rocky reef fish community structure around islands and headlands of a temperate marine protected area

The University of Newcastle and NSW Department of Primary Industries provided funding with research conducted under NSW DPI Animal Care and Ethics Committee permit 10/09

Rocky reef fish community composition remains stable throughout seasons and El Niño/La Niña events in the southern Gulf of California

The main effects of El Niño and La Niña on fish are increases in mortality rates, abundance and recruitment variation, and expansion/restriction in the range of distribution and spawning areas. Potentially, the interactions with seasonal effects can further exacerbate or dampen fluctuations in these parameters. The objective of this work, therefore, was to characterize the possible differences in the reef fish community structure in two seasons of the year (warm/cold) and between years (2010/2012) following El Niño-La Niña events. There were no significant differences in mean species richness between years. Furthermore, although more than twice the number of individuals was observed in the year after La Niña (2012) compared to the year following El Niño (2010), there were no significant differences with respect to mean abundance per transect. The total number of species recorded was slightly higher in the cold season, with 68 species across both years. In contrast, the total abundance was higher in the warm season. However, differences between seasons were neither significant for mean species richness nor for mean abundance. Neither season nor year exhibited a significant effect on community composition. The cold season in the Gulf of California is characterized by intense winds which generate a greater mixed layer; this, in turn, increases productivity, with cascading effects on higher trophic levels. In contrast, the presence of nitrogen-fixing picocyanobacteria which increase the levels of primary production may be a factor leading to maintaining a similar fish abundance in the warm season. Fluctuations between seasons and years of study were observed for some individual species, which may be related to oceanic productivity and reproductive periods. The results obtained in this work indicate that seasonality and climatic phenomena such El Niño and La Niña do not have a marked effect on community attributes of rocky reef fish in the southern Gulf of California, which apparently form a seasonally stable community, despite some fluctuations in individual species.

Latitudinal variation in structure and function of conspicuous reef fish assemblages along the western Gulf of California

The Gulf of California is characterized by great biodiversity, high biological productivity and important fisheries. Studies on community structure of the reef fish fauna in the region have been conducted mainly in central and southern areas and, except for a few studies that have focused on cryptic species, there are no comparisons of the fish assemblages along this 1,600 km sea. In this study, we examine how diversity and community structure of rocky reef fishes vary with the latitude in the north, central and southern part of the west side of the Gulf of California. We conducted stationary visual censuses in observation cylinders (5 m radius) in 6 locations between Bahia de los Angeles (29° N) and Los Cabos (22° N) and estimated the following ecological descriptors and indexes: species richness, abundance, Shannon diversity, Pielou evenness, average taxonomic distinctness, and average trophic level. In addition, we used ordination analysis to determine the degree of similarity among study areas. Our results identified 3 distinct zones: north (29° N), central (27° N to 24° N) and south (24° N to 22° N).

Condition of Coral Fish in Tapanuli Tengah Waters

Coral reefs is a center for biodiversity in the world with a complex architecture and has an aesthetics value. It also offers beneficial for human being in many aspects such as economics, social and culture. Research was conducted in July 2016 and aim to understand community structure and biomass of coral reef fishes in Tapanuli Tengah waters. Result from all stations in Tapanuli Tengah waters showed that 49 species from seven families of economically reef fish i.e. Acanthuridae, Serranidae, Haemulidae, Lutjanidae, Lehtrinidae, Siganidae and Scaridae were found. Density average of those seven families was 163 individual/350 m<sup>2</sup> or 4668 individual/ha with biomass average of 1.564 ton/ha. Moreover, biomass from other target fishes from nine families was accounted as 0.56 ton/ha. On the other hand, over all coralifore fish represented by Chaetodontidae was eight species from two genus, namely <em>Chaetodon</em> and <em>Heniochus </em>with four species. The density from family Chaetodotidae varies among station between 3-28 individual/350 m<sup>2</sup>

Strong effects of coral species on the diversity and structure of reef fish communities: A multi-scale analysis.

While there is increasing evidence for habitat specialization in coral reef fishes, the extent to which different corals support different fish communities is not well understood. Here we quantitatively assess the relative importance of different coral species in structuring fish communities and evaluate whether sampling scale and coral colony size affect the perceived strength of fish-habitat relationships. Fish communities present on colonies of eight coral species (Porites cylindrica, Echinopora horrida, Hydnophora rigida, Stylophora pistillata, Seriatopora hystrix, Acropora formosa, A. tenuis and A. millepora) were examined in the Lizard Island lagoon, Great Barrier Reef, Australia. Additionally, the differences in fish communities supported by three coral species (P. cylindrica, E. horrida, H. rigida) were investigated at three spatial scales of sampling (2x2 m, 1x1 m, 0.5x0.5 m). Substantial differences in fish communities were observed across the different coral species, with E. horrida and H. rigida supporting the most fish species and individuals. Coral species explained more of the variability in fish species richness (20.9–53.6%), than in fish abundance (0–15%). Most coral species supported distinctive fish communities, with dissimilarities ranging from 50 to 90%. For three focal coral species, a greater amount of total variation in fish species richness and fish abundance was evident at a larger scale of sampling. Together, these results indicate that the structure of reef fish communities is finely tuned to coral species. Loss of preferred coral species could have profound effects on reef fish biodiversity, potentially more so than would be predicted on the basis of declining coral cover alone.

Species’ thermal ranges predict changes in reef fish community structure during 8 years of extreme temperature variation

AbstractAimTo assess whether observed thermal bounds in species’ latitudinal ranges (i.e., realized thermal niches) can be used to predict patterns of occurrence and abundance changes observed during a marine heatwave, relative to other important life history and functional traits.LocationRottnest Island, Western Australia.MethodsA time series of standardized quantitative surveys of reef fishes spanning 8 years of pronounced ocean temperature change is used to test whether accurate predictions on shifts in species occupancy and abundance are possible using species traits.ResultsSpecies‐level responses in occurrence and abundance were closely related to the mid‐point of their realized thermal niche, more so than body size, range size or trophic level. Most of the species that disappeared from survey counts during the heatwave were characterized by geographic ranges that did not extend to latitudes with temperatures equivalent to the ocean temperature peak during the heatwave. We thus find support for the hypothesis that current distribution limits are set directly or indirectly by temperature and are highly responsive to ocean temperature variability.Main conclusionsOur study shows that reef fish community structure can change very quickly when exposed to extreme thermal anomalies, in directions predicted from the realized thermal niche of the species present. Such predictions can thus identify species that will be most responsive to changing ocean climate. Continued warming, coupled with periodic extreme heat events, may lead to the loss of ecosystem services and ecological functions, as mobile species relocate to more hospitable climes, while less mobile species may head towards extinction.

Characterization of the fish assemblage in different coastal habitats in an area heavily impacted by tourism

Strong relationships exist between reef fishes and their habitat, anthropogenic habitat alterations may lead variations in the associated fish. Knowledge of fish species distribution over coastal areas heavily impacted by tourism over the Mexican Central Pacific is scarce. This work aims to identify the reef fish species on different coastal habitats (sand, rock, mud) present in Puerto Marques Bay. The fish community was characterized in terms of species richness, abundance, feeding behavior and was further assessed using similarity analysis. The number of species and the relative abundance of fish species recorded varied significantly among the habitats (ANOSIM test: R = 0.676, P < 0.01, 999 permutations). In rocky areas, the highest value of richness, exclusive species and the number of organisms were recorded. In comparison with soft bottoms, the complexity of hard substrates plays a significant role in reducing prey abundances and providing nesting sites and different food resources such as invertebrates and macroalgae. Mugil cephalus was the only species recorded with muddy habitat affinity, where it feeds on detritus. Predatory species like Caranx caballus, Lutjanus jordani and Lutjanus peru, generally associated with complex rocky substrates were recorded exclusively in sandy areas near to the tourist marina. Although our data do not allow to conclude the anthropogenic outcomes in the reef fish community structure, they suggest that fish assemblage from sandy bottoms could be affected by the presence of artificial structures.

Diversidad de las comunidades de peces en dos áreas marinas protegidas del Caribe y su relación con el pez león

Lionfish (Pterois volitans) invaded the Caribbean region with the potential to alter the composition and structure of native coral reef fish communities. The objective of this study was to analyze the diversity indices of these fish communities potentially affected by lionfish predation and to compare with pre-invasion data. The study was undertaken in two Caribbean marine protected areas (MPAs): Guanahacabibes National Park (PNG) in W Cuba and Xcalak Reefs National Park (PNAX) in S Quintana Roo. We carried out visual censuses of fish species in reef habitats during the dry and rainy seasons of the period 2013-2015. For this, nine sites were defined and evaluated using stationary counts. Our results showed higher species richness (43.47 ± 5.14) and mean abundance (0.76 ± 1.25) in PNG than in PNAX (40.22 ± 4.96, 0.19 ± 0.46, respectively). Diversity decreased after the arrival of lionfish in a single site of PNG and in two sites of the PNAX, but apparently, these results are more related to the fishing activity effect than to the lionfish presence. Based on the results and assuming that changes in the native fish communities by lionfish may not yet be detected, we recommend to continue the monitoring community descriptions in order to detect future changes in native fish communities.

Long-term monitoring of coral reef fish assemblages in the Western central pacific

Throughout the tropics, coral reef ecosystems, which are critically important to people, have been greatly altered by humans. Differentiating human impacts from natural drivers of ecosystem state is essential to effective management. Here we present a dataset from a large-scale monitoring program that surveys coral reef fish assemblages and habitats encompassing the bulk of the US-affiliated tropical Pacific, and spanning wide gradients in both natural drivers and human impact. Currently, this includes >5,500 surveys from 39 islands and atolls in Hawaii (including the main and Northwestern Hawaiian Islands) and affiliated geo-political regions of American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the Pacific Remote Islands Areas. The dataset spans 2010–2017, during which time, each region was visited at least every three years, and ~500–1,000 surveys performed annually. This standardised dataset is a powerful resource that can be used to understand how human, environmental and oceanographic conditions influence coral reef fish community structure and function, providing a basis for research to support effective management outcomes.

Atoll-scale patterns in coral reef community structure: Human signatures on Ulithi Atoll, Micronesia.

The dynamic relationship between reefs and the people who utilize them at a subsistence level is poorly understood. This paper characterizes atoll-scale patterns in shallow coral reef habitat and fish community structure, and correlates these with environmental characteristics and anthropogenic factors, critical to conservation efforts for the reefs and the people who depend on them. Hierarchical clustering analyses by site for benthic composition and fish community resulted in the same 3 major clusters: cluster 1–oceanic (close proximity to deep water) and uninhabited (low human impact); cluster 2–oceanic and inhabited (high human impact); and cluster 3–lagoonal (facing the inside of the lagoon) and inhabited (highest human impact). Distance from village, reef exposure to deep water and human population size had the greatest effect in predicting the fish and benthic community structure. Our study demonstrates a strong association between benthic and fish community structure and human use across the Ulithi Atoll (Yap State, Federated States of Micronesia) and confirms a pattern observed by local people that an ‘opportunistic’ scleractinian coral (Montipora sp.) is associated with more highly impacted reefs. Our findings suggest that small human populations (subsistence fishing) can nevertheless have considerable ecological impacts on reefs due, in part, to changes in fishing practices rather than overfishing per se, as well as larger global trends. Findings from this work can assist in building local capacity to manage reef resources across an atoll-wide scale, and illustrates the importance of anthropogenic impact even in small communities.

Coral Fishes At Artificial Reef In Bunaken National Park Arakan, South Minahasa Regency

Artificial reefs already placed in the coast of the village of Arakan, South Minahasa regency since June 2015. Artificial reef, that would be the location of research are concrete and iron, mostly be the medium of coral transplantation. The pupose of the research are (1). To know the species coral reef fish (2). To know the number of each species and the density of the coral reef fish (3). To know the structure of coral reef fish communities. Data retrieval be done use with Visual Census Method in the 51 squaremeter area (lenght = 8,5 m, width = 6 m). This research find 15 families with 29 coral reef fish species and 1341 individual. The diversity index of artificial reefs with moderate diversity index and relative abudance is found in species Dascyllus trimaculatus 34,731 %, Plotosus lineatus 21,593 %, and Dascyllus reticulatus 21,174 %.Keywords: Artificial reef, Community Structure, Arakan. ABSTRAKTerumbu buatan sudah diletakan pada perairan desa Arakan Kabupaten Minahasa Selatan pada bulan Juni 2015. Terumbu buatan yang menjadi lokasi penelitian berjenis beton dan besi, model yang terbuat dari besi lebih banyak diarahkan sebagai media transplantasi karang. Penelitian ini bertujuan untuk (1) Mengetahui kekayaan spesies ikan karang (2) Mengetahui kelimpahan individu dan kepadatan relatif ikan karang (3) Mengetahui struktur komunitas ikan karang. Pegambilan data dilakukan menggunakan metode Sensus Visual dengan luas pengamatan pada terumbu buatan seluas 51 m2 (panjang = 8,5 meter dan lebar = 6 meter). Penelitian ini menemukan 15 famili dengan 29 spesies ikan karang dan kelimpahan individu total 1341 individu. Indeks keanekaragaman di daerah terumbu buatan dengan nilai indeks keanegaraman yang sedang dengan indeks dominasi rendah dan kelimpahan relatif terdapat pada spesies Dascyllus trimaculatus dengan nilai 34,731 %, Plotosus lineatus dengan nilai 21,593 %, dan Dascyllus reticulatus dengan nilai 21,174 %.Kata Kunci : Terumbu Buatan, Struktur Komunitas, Arakan.

Trophic designation and live coral cover predict changes in reef-fish community structure along a shallow to mesophotic gradient in Hawaii

Reef-fish community structure and habitat associations are well documented for shallow coral reefs ( 30 m). We documented the community structure of fishes and seafloor habitat composition through visual observations at depth intervals from 3 to 50 m in West Hawaii. Community structure changed gradually with depth, with more than 78% of fish species observed at mesophotic depths also found in shallow reef habitats. Depth explained 17% of the variation in reef-fish community structure; live coral cover explained 10% and prevalence of sand accounted for 7% of the fitted variation indicating that depth-related factors and coral habitat play a predominant role in structuring these communities. Differences in community structure also appear to be linked closely with feeding behavior. Trophic designation accounted for 31% of the fitted variation, with changes in herbivore abundance accounting for 10% of the variation. These findings suggest that changes in reef-fish community composition from shallow to mesophotic environments are largely influenced by trophic position, coral habitat and indirect effects of depth itself.

Resetting predator baselines in coral reef ecosystems

What did coral reef ecosystems look like before human impacts became pervasive? Early efforts to reconstruct baselines resulted in the controversial suggestion that pristine coral reefs have inverted trophic pyramids, with disproportionally large top predator biomass. The validity of the coral reef inverted trophic pyramid has been questioned, but until now, was not resolved empirically. We use data from an eight-year tag-recapture program with spatially explicit, capture-recapture models to re-examine the population size and density of a key top predator at Palmyra atoll, the same location that inspired the idea of inverted trophic biomass pyramids in coral reef ecosystems. Given that animal movement is suspected to have significantly biased early biomass estimates of highly mobile top predators, we focused our reassessment on the most mobile and most abundant predator at Palmyra, the grey reef shark (Carcharhinus amblyrhynchos). We estimated a density of 21.3 (95% CI 17.8, 24.7) grey reef sharks/km2, which is an order of magnitude lower than the estimates that suggested an inverted trophic pyramid. Our results indicate that the trophic structure of an unexploited reef fish community is not inverted, and that even healthy top predator populations may be considerably smaller, and more precarious, than previously thought.