Coral Reef Fish Species Research Articles

The distribution of coral reef fish biodiversity on Bontosua Island, Spermonde Archipelago, South Sulawesi Province

Background: Bontosua Island, located in the Spermonde Archipelago, is one of the strategic and historical islands in the region. The island plays a vital role in ecosystem conservation efforts by the local community, who are committed to preserving their natural environment. With dynamic ecosystem conditions, it is essential to understand the seabed cover and biodiversity on the island to support more effective conservation efforts. Methods: This study was conducted from March to September 2022 to mark the seabed cover of Bontosua Island and understand the relationships between coral reef fish species and the ecosystem. The method used was a stationary visual census, followed by descriptive analysis and one-way ANOVA to assess the biodiversity and diversity of coral reefs. Findings: The results showed a total of 1,306 coral reef fish from 9 families with 63 species identified, including the families Chaetodontidae, Serranidae, Lutjanidae, Haemulidae, Lethrinidae, Scaridae, Acanthuridae, and Siganidae. The families with the highest citations were Scaridae, Acanthuridae, and Siganidae. The highest coral reef fish were found in the north, west, and southwest of the island, where live coral areas are more dominant. Conclusion: This study shows that Bontosua Island has significant coral reef diversity, and certain areas, such as the north and southwest sides, have higher reported fish. These findings indicate the importance of these areas in conservation efforts. Novelty/Originality: This study provides a comprehensive picture of the seabed cover and coral reef fish diversity in Bontosua Island, which has yet to be widely discussed in previous studies. These findings provide a scientific basis for more targeted conservation strategies and help improve understanding of the dynamics of coral reef ecosystems in the Spermonde Islands.. Novelty/Originality of this article: This study proposes developing a community-based coral reef monitoring system that integrates local knowledge with digital mapping technology, aiming to increase the effectiveness of conservation and management efforts of marine resources on small islands.

First assessment of persistent organic pollutants and halogenated natural compounds in an omnivorous resident coral-reef fish species, black triggerfish, Melichthys niger, from an Atlantic oceanic island, Brazil

Studies on the occurrence of POPs and other persistent compounds in pristine areas are extremely valuable, as they offer insights on the long-range transportation of POPs and the occurrence of natural compound producers' areas. In this regard, this study aimed to report data of both anthropogenic (polychlorinated biphenyls, PCBs, and polybrominated diphenyl ethers, PBDEs) and natural (methoxylated PBDEs, MeO-BDEs) compounds in tissues of the black triggerfish, Melichthys niger (Tetraodontiformes, Balistidae), specimens (n = 30) sampled in 2018 during a scientific expedition conducted at Trindade Island. Concentrations of ∑28PCBs ranged from 73 to 1052 ng g−1 lw in liver, 334 to 1981 ng g−1 lw in gonads, and 20 to 257 ng g−1 lw in muscle, with the predominance of PCB-180 in liver and PCB-52 in gonad and muscle. Concentrations of ∑7PBDEs ranged from <LOD to 1.8 ng g−1 lw in liver, <LOD to 14 ng g−1 lw in muscle, and they were < LOD in gonads. The BDE-47 was the most representative congener detected in liver and muscle. Mean concentrations of ∑8MeO-BDEs were 270 ng g−1 lw, 442 ng g−1 lw, and 70 ng g−1 lw in liver, gonad, and muscle, respectively. The 2-MeO-BDE-68 was the most representative congener among MeO-BDEs. The mobilization of lower chlorinated PCBs from liver to other tissues, with possible retention of higher chlorinated PCBs in liver, can be a factor of concern considering the chronic exposure of those fish. PBDEs and MeO-BDEs in fish from remote environments were reported in a low number of studies worldwide. Considering that remote sites face environmental pollution either directly by anthropogenic influence or by long-range transportation, more studies on the occurrence of persistent compounds in these environments are paramount, and it is fundamental to understand the dispersion and accumulation of POPs.

Challenging trophic position assessments in complex ecosystems: Calculation method, choice of baseline, trophic enrichment factors, season and feeding guild do matter: A case study from Marquesas Islands coral reefs.

Assessments of ecosystem functioning are a fundamental ecological challenge and an essential foundation for ecosystem-based management. Species trophic position (TP) is essential to characterize food web architecture. However, despite the intuitive nature of the concept, empirically estimating TP is a challenging task due to the complexity of trophic interaction networks. Various methods are proposed to assess TPs, including using different sources of organic matter at the base of the food web (the 'baseline'). However, it is often not clear which methodological approach and which baseline choices are the most reliable. Using an ecosystem-wide assessment of a tropical reef (Marquesas Islands, with available data for 70 coral reef invertebrate and fish species), we tested whether different commonly used TP estimation methods yield similar results and, if not, whether it is possible to identify the most reliable method. We found significant differences in TP estimates of up to 1.7 TPs for the same species, depending on the method and the baseline used. When using bulk stable isotope data, the choice of the baseline significantly impacted TP values. Indeed, while nitrogen stable isotope (δ15N) values of macroalgae led to consistent TP estimates, those using phytoplankton generated unrealistically low TP estimates. The use of a conventional enrichment factor (i.e. 3.4‰) or a 'variable' enrichment factor (i.e. according to feeding guilds) also produced clear discrepancies between TP estimates. TPs obtained with δ15N values of source amino acids (compound-specific isotope analysis) were close to those assessed with macroalgae. An opposite seasonal pattern was found, with significantly lower TPs in winter than in summer for most species, with particularly pronounced differences for lower TP species. We use the observed differences to discuss possible drivers of the diverging TP estimates and the potential ecological implications.

Initial Assessment of the Benthic Profile and Reef Fish Composition of the Damilisan Marine Sanctuary, Miagao, Iloilo, Philippines

Coral reefs are among the world’s most diverse and productive ecosystems. They provide valuable ecosystem services, including support for fisheries production and the livelihood of coastal communities. However, coral reefs are also threatened by anthropogenic and climate stressors. Establishing a marine protected area (MPA) is a typical coastal management tool widely used in the Philippines for conserving coral reefs and managing the fishing effort. This study presents initial information on the benthic and fish community profiles of the Damilisan Marine Sanctuary (DMS) in Miagao, Iloilo, Philippines. A modified point-intercept transect method was used to characterize the benthic profile, while the underwater visual census (UVC) was used to determine the fish community profile (diversity and density). The substrate was mainly composed of hard coral (HC) (39.3±18.3%), and the common HC observed were massive Porites and Goniopora, each contributing 12.8% of the total HC cover. Twenty coral reef fish species belonging to 10 families were identified during the UVC and had an overall density of 99±69 ind./1000 m2. Damselfishes (Family Pomacentridae) was the most abundant family (23±0.4 ind./500 m2), while Lutjanus semicinctus was the most abundant species (8.5±1.4 ind./500 m2). It is recommended that regular coral reef monitoring surveys be conducted in the DMS and in other MPAs in Miagao to monitor trends and changes in the HC cover and reef fish density and diversity in the MPA.

The Relationship between Mean Length at Maturity and Maximum Length in Coral Reef Fish

This article proposes a mechanism that triggers first maturation and spawning in coral reef (bony) fish, which allows for predicting their length at first maturity. Thus, mean lengths at first maturity (Lm) and the corresponding maximum lengths (Lmax) in 207 populations of 131 species of coral reef fish were assembled and used to test the hypotheses that (a) there is, in coral reef fish, a single value of a size-related parameter acting as a trigger for their maturation and eventual spawning, and (b) that this single value is statistically the same as that published previously for other bony fish. The results, based on the assembled Lm and Lmax data and on estimates of the parameter D, which link the length of fish with the relative surface of their gills, covered 44 families and Lmax values ranging from 1.8 to 181.6 cm and confirmed that the threshold in (a) exists. Also, we assessed (in b) that this threshold value, i.e., LmaxD/LmD = 1.35 (±0.02), is not statistically different from similar estimates for other groups of teleosts, notably semelparous salmonids, cichlids, sturgeons and Chinese and Turkish freshwater and marine fish. One implication is that given ocean warming and deoxygenation, coral reef fish will not only be smaller than they currently are, but also mature and spawn at smaller sizes, and thus produce fewer, smaller eggs.

Effects of flow speed and prey density on the rate and efficiency of prey capture in zooplanktivorous coral-reef fishes

Holling’s classical functional response model describes the mechanistic foundations of the relationships between predation rate and prey density. As such, the model is pertinent to predators that actively search for prey, but not to stationary predators in which additional factors, such as flow speed, determine the rates of prey encounter. The main objective of this study was to measure the rates and corresponding efficiencies of zooplanktivory among different common species of coral-reef fishes under a wide range of prey densities and current speeds. All our experiments were carried out in a flume with different combinations of flow speeds (3-28.5 cm/s) and prey densities (210 - 1050 prey m-3). Nauplii of Artemia salina were used as prey. Despite major differences in the taxonomic origin of the studied species, their morphologies, and the types of shelters they use, the foraging performances of the fish, their predation rates, and the way those rates were affected by prey density and flow speed were surprisingly similar. Under a fixed prey density, capture rates did not change much as function of flow speed. Under conditions of equal prey flux, predation rates were always higher under conditions of high density and weaker flow than under lower density and faster flow. A sharp decline in capture efficiency with increasing flow speed was explained by a corresponding narrowing of the fish’s body orientation relative to the flow. In other words, with increasing flow speed, the fish gradually became more-narrowly oriented head-on onto the flow, exhibiting a decrease in the frequency of body turns (“maneuverability”). These trends, especially the reduced maneuverability under strong currents, can explain our findings that predation rates did not increase when the flow, hence prey flux, increased. Inter-specific differences in predation rates and efficiencies, however small, agree well with observed differences in the type of habitats the different species occupy.

Modeling the spatial distribution of numbers of coral reef fish species and community types in the Western Indian Ocean faunal province

Predicting and mapping coral reef diversity at moderate scales can assist spatial planning and prioritizing conservation activities. We made coarse-scale (6.25 km2) predictive models for numbers of coral reef fish species and community composition starting with a spatially complete database of 70 environmental variables available for 7039 mapped reef cells in the Western Indian Ocean. An ensemble model was created from a process of variable elimination and selectivity to make the best predictions irrespective of human influences. This best model was compared to models using preselected variables commonly used to evaluate climate change and human fishing and water quality influences. Many variables (~27) contributed to the best number of species and community composition models, but local variables of biomass, depth, and retention connectivity were dominant predictors. The key human-influenced variables included fish biomass and distance to human populations, with weaker associations with sediments and nutrients. Climate-influenced variables were generally weaker and included median sea surface temperature (SST) with contributions in declining order from SST kurtosis, bimodality, excess summer heat, SST skewness, SST rate of rise, and coral cover. Community composition variability was best explained by 2 dominant community richness axes of damselfishes-angelfishes and butterflyfishes-parrotfishes. Numbers of damselfish-angelfish species were ecologically separated by depth, and damselfishes declined with increasing depth, median temperature, cumulative excess heat, rate of temperature rise, and chronic temperature stresses. Species of butterflyfish-parrotfish separated by median temperature, and butterflyfish numbers declined with increasing temperature, chronic and acute temperature variability, and the rate of temperature rise. Several fish diversity hotspots were found in the East African Coastal Current Ecoregion centered in Tanzania, followed by Mayotte, southern Kenya, and northern Mozambique. If biomass can be maintained, the broad distributions of species combined with compensatory community responses should maintain high diversity and ecological resilience to climate change and other human stressors.

Nocturnal substrate association of four coral reef fish groups (parrotfishes, surgeonfishes, groupers and butterflyfishes) in relation to substrate architectural characteristics.

Although numerous coral reef fish species utilize substrates with high structural complexities as habitats and refuge spaces, quantitative analysis of nocturnal fish substrate associations has not been sufficiently examined yet. The aims of the present study were to clarify the nocturnal substrate associations of 17 coral reef fish species (nine parrotfish, two surgeonfish, two grouper and four butterflyfish) in relation to substrate architectural characteristics. Substrate architectural characteristics were categorized into seven types: (1) eave-like space, (2) large inter-branch space, (3) overhang by protrusion of fine branching structure, (4) overhang by coarse structure, (5) uneven structure without large space or overhang, (6) flat and (7) macroalgae. Overall, fishes were primarily associated with three architectural characteristics (eave-like space, large inter-branch space and overhang by coarse structure). The main providers of these three architectural characteristics were tabular and corymbose Acropora, staghorn Acropora, and rock. Species-specific significant positive associations with particular architectural characteristics were found as follows. For the nine parrotfish species, Chlorurus microrhinos with large inter-branch space and overhang by coarse structure; Ch. spilurus with eave-like space and large inter-branch space; Hipposcarus longiceps with large inter-branch space; Scarus ghobban with overhang by coarse structure; five species (Scarus forsteni, S. niger, S. oviceps, S. rivulatus and S.schlegeli) with eave-like space. For the two surgeonfish species, Naso unicornis with overhang by coarse structure; N. lituratus with eave-like space. For the two grouper species, Plectropomus leopardus with eave-like space; Epinephelus ongus with overhang by coarse structure. For the four butterflyfish species, Chaetodon trifascialis with eave-like space and large inter-branch space; C. lunulatus and C. ephippium with large inter-branch space; C. auriga showed no significant associations with any architectural characteristics. Four species (Ch. microrhinos, H. longiceps, S. niger and N. unicornis) also showed clear variations in substrate associations among the different fish size classes. Since parrotfishes, surgeonfishes and groupers are main fisheries targets in coral reefs, conservation and restoration of coral species that provide eave-like space (tabular and corymbose Acropora) and large inter-branch space (staghorn Acropora) as well as hard substrates with coarse structure that provide overhang (rock) should be considered for effective fisheries management in coral reefs. For butterflyfishes, coral species that provide eave-like space (tabular Acropora) and large inter-branch space (staghorn Acropora) should also be conserved and restored for provision of sleeping sites.

Biodiversity of coral reefs ecosystem in Sabu Raijua Waters

The waters of Sabu Raijua are included in World’s Coral Triangle Region, which has high-potential Coral Reefs Ecosystems that have not been widely revealed. The remote location and erratic wave weather conditions give challenges in surveying biodiversity coral reef ecosystems. The observation of the Coral Reef ecosystem has been carried out at 12 stations in Sabu Raijua using underwater photo transect to determine the coral cover percentage, line transect for benthos noncoral, belt transect for community structure of coral reefs, and visual census method for measuring reef fish community. The result of coral reef condition is categorized as moderate, where the average live hard coral cover percentage is 22%, dominated by coral massive and submassive. Hard coral that found as many as 47 genera dominated by Porites, Galaxea, and Favites. There are 111 species of coral reef fishes have been identified. Benthos noncoral found as many as 109 species.

Winners and losers of reef flattening: an assessment of coral reef fish species and traits

Anthropogenic stressors are causing widespread coral mortality, leading to loss of coral cover and decreased structural complexity that threatens reef biodiversity, functioning, and ecosystem services. Reef fishes are intimately linked to coral reef complexity, but we lack a generic understanding of which species are particularly affected by reef flattening and what traits make them susceptible. We used extensive species‐ and trait‐based analyses to build a framework for western Atlantic fish association with both structural complexity and coral cover to better understand the implications of reef degradation. These analyses also highlighted the relative importance of live coral versus the structure it provides to reef fishes, which currently remains unclear. We modeled how 25 biophysical and anthropogenic factors correlated with the densities of 109 fish species across 3292 Floridian reef sites. The importance of a metric of structural complexity and coral cover to the abundance of each species was then isolated. Species with positive associations were categorized as likely future ‘losers' and negative associations as ‘winners'. We predicted that 53% of species will be losers on low‐relief reefs, while only 11% were losers with decreased coral cover. We found morphological, behavioral, and ecological traits, not phylogeny, mediate species' responses to reef degradation and that the loss of structure seemed more critical than the loss of coral cover. Eight traits explained 79.7% of the variation in species' associations with relief and six traits explained 27.8% of associations with coral cover. Smaller, streamlined, habitat and trophic generalists are more likely winners on flattened reefs and large‐bodied predators, among other taxa, are likely losers of reef flattening. Identifying these important traits provides insight into mechanisms that may link fish and complex habitats, which allows us to better predict assemblage‐wide responses to future reef flattening.

Genome-wide association study (GWAS) analysis of black color trait in the leopard coral grouper (Plectropomus leopardus) using whole genome resequencing

The leopard coral grouper (Plectropomus leopardus) is a coral reef fish species that exhibits rapid and diverse color variation. However, the presence of melanoma and the high proportion of individuals displaying black color in artificial breeding have led to reduced economic and ornamental value. To pinpoint single nucleotide polymorphisms (SNPs) and potential genes linked to the black pigmentation characteristic in this particular species, This study gathered a cohort of 360 specimens from diverse origins and conducted a comprehensive genome-wide association analysis (GWAS) employing whole-genome resequencing. As a result, 57 SNPs related to the black skin trait were identified, and a grand total of 158 genes were annotated within 50 kb of these SNPs. Subsequently, GWAS was applied to three populations (LED, QHH, and QHL), and the corresponding results were compared with the analysis results of the total population. The results of the four GWAS models showed significant enrichment in Rap1 signaling pathway, melanin biosynthesis, metabolic pathways, tyrosine metabolism, cAMP signaling pathway, AMPK signaling pathway, PI3K-Akt signaling pathway, EGFR tyrosine kinase inhibitor resistance, HIF-1 signaling pathway, Ras signaling pathway, MAPK signaling pathway, etc. (p < 0.05), which were mainly associated with eleven genes (POL4, MET, E2F2, COMT, ZBED1, TYRP2, FOXP2, THIKA, LORF2, MYH16 and SOX2). Significant differences (p < 0.05) were observed in the expression of all 11 genes in the dorsal skin tissue, in 10 genes except COMT in the ventral skin tissue, and in all 11 genes in the caudal fin tissue. These findings imply that the control of body color in the P. leopardus is the result of the joint action of multiple genes and signaling pathways. These findings will contribute to a more profound comprehension of the genetic attributes that underlie the development of black skin in the vibrant P. leopardus, thus furnishing a theoretical foundation for genetic enhancement.

Transitions from coral to sponge-dominated states alter trophodynamics in associated coral reef fish assemblages

1. Coral reefs are extremely productive ecosystems, but widespread changes to benthic community structure resulting from anthropogenic impacts are likely to impact the transfer of organic matter between trophic levels, altering trophodynamics and functional diversity. 2. We used stable isotope analysis to investigate differences in resource availability, niche width and trophic diversity of seven coral reef fish species representing key functional feeding groups on a sponge-dominated reef and an adjacent, coral-dominated reef. 3. Four out of seven fish species had wider isotopic niches at the sponge-dominated reef compared to the coral-dominated reef, including the obligate corallivore. The proximity of the isotopic niche of the obligate corallivore to the isotopic niche of the detritivore suggests that the obligate corallivore supplemented its diet with detritus at the sponge-dominated reef. 4. Fish sampled at the sponge-dominated reef had a significantly lower mean trophic position, used a lower range of resources (based on δ13C range) and obtained more carbon from benthic production than at the coral-dominated reef. Trophic diversity was lower and functional redundancy higher at the sponge-dominated reef, suggesting that fish on the sponge reef had more similar diets to each other than at the coral-dominated site. 5. Observed differences in trophic structure between the two sites are likely due to fewer organic matter pathways supporting secondary production at the sponge-dominated reef, suggesting that transitions sponge-dominated systems will reduce community stability by eroding the potential for niche partitioning and species co-existence.

Composition and Long-Term Variation Characteristics of Coral Reef Fish Species in Yongle Atoll, Xisha Islands, China.

Yongle Atoll was the largest atoll in the Xisha Islands of the South China Sea, and it was a coral reef ecosystem with important ecological and economic values. In order to better protect and manage the coral reef fish resources in Yongle Atoll, we analyzed field survey data from artisanal fishery, catches, and underwater video from 2020 to 2022 and combined historical research to explore the changes in fish species composition and community structure in Yongle Atoll over the past 50 years. The results showed that a total of 336 species of fish were found on Yongle Atoll, belonging to 17 orders and 60 families. Among them, Perciformes had the most fish species with 259 species accounting for 77.08% of the total number of species. The number of fish species in the coral reef of Yongle Atoll was exponentially correlated with its corresponding maximum length and significantly decreases with its increase. The fish community structure of Yongle Atoll changed, and the proportion of large carnivorous fish decreased significantly, while the proportion of small-sized and medium-sized fish increased. At the same time, Yongle Atoll has 18 species of fish listed on the IUCN Red List, 15 of which are large fish. The average taxonomic distinctness (Delta+, Δ+) and the variation taxonomic distinctness (Lambda+, Λ+) in 2020-2022 were lower than the historical data, and the number of fish orders, families, and genera in Yongle Atoll has decreased significantly, which indicates that the current coral reef fish species in Yongle Atoll have closer relatives and higher fish species uniformity. In addition, the similarity of fish species in Yongle Atoll was relatively low at various time periods, further proving that the fish community structure has undergone significant variation. In general, due to multiple impacts, such as overfishing, fishing methods, environmental changes, and habitat degradation, the fish species composition of Yongle Atoll may have basically evolved from carnivorous to herbivorous, from large fish to small fish, and from complexity to simplicity, leaving Yongle Atoll in an unstable state. Therefore, we need to strengthen the continuous monitoring of the coral reef ecosystem in Yongle Atoll to achieve the protection and restoration of its ecological environment and fishery resources, as well as sustainable utilization and management.

The role of fish feces for nutrient cycling on coral reefs

Consumers play an important role in biogeochemical cycles through the consumption and release of essential elements such as carbon (C), nitrogen (N), and phosphorus (P). Indeed, a large proportion of consumed elements are released into the environment in inorganic (i.e. excretion) or organic form (i.e. egestion). On coral reefs, fishes represent the bulk of consumer biomass and thus play a key role in the recycling of nutrients. In recent years, excretion rates have been studied intensively, but less is known about the rate and quality of coral reef fish egestion. In this study, we quantify the elemental contents of fish feces, estimate absorption efficiencies and compare egestion and excretion rates for 51 coral reef fish species. We show that elemental concentrations decrease remarkably little from food to feces. This is due to extremely low absorption efficiencies, resulting in the egestion of large amounts of energy and nutrients. Moreover, we show that while the quality of fish feces varies across trophic guilds, it remains highly variable within trophic guilds. Finally, we demonstrate that the release of N and P through egestion outweighs the amount of nutrients recycled through excretion. Our study highlights the need to incorporate animal egestion into assessments of ecosystem functioning and food web structure.

Importance of coastal vegetated habitats for tropical marine fishes in the Red Sea

Marine vegetated habitats such as seagrass, mangroves, and macroalgae are common along tropical coastlines globally and provide habitats for a diversity of fishes, including juvenile fish and species found on coral reefs. Understanding the use of these habitats by different fish species and life stages is fundamental to spatial planning, fisheries management, and conservation. While previous studies have focused on the habitat potential of seagrass, macroalgae, or mangroves for coral reef fish independently, it is important to consider their combined roles, as tropical seascapes are often mosaics of such habitats. In this study, we evaluated habitat associations across life stages for fish species in coral reefs, seagrasses, macroalgae, and mangroves in Saudi Arabia’s central Red Sea. Through in situ visual surveys, we documented 36% of local coral reef fish species in one or more vegetated habitats, with the fraction of coral reef species utilizing macroalgae or seagrass much greater than that of mangroves (29%, 18%, and 6%, respectively). Mangroves hosted mainly juvenile fish (83% of observed population) and macroalgae hosted the largest proportion of herbivores (39% of observed population), suggesting that each environment offers different combinations of resources (food and shelter), and a mix of these habitats could support biological connectivity across a seascape. Species targeted by local fisheries made up 37% of the species documented in vegetated habitats. The use of multiple habitat types by juvenile and commercially important fishes in the Red Sea underscores the need for a holistic approach to habitat protection.Graphical abstract

Diversity and Antimicrobial Activity of Intestinal Fungi from Three Species of Coral Reef Fish.

Although intestinal microbiota play crucial roles in fish digestion and health, little is known about intestinal fungi in fish. This study investigated the intestinal fungal diversity of three coral reef fish (Lates calcarifer, Trachinotus blochii, and Lutjanus argentimaculatus) from the South China Sea using a culturable method. A total of 387 isolates were recovered and identified by sequencing their internal transcribed spacer sequences, belonging to 29 known fungal species. The similarity of fungal communities in the intestines of the three fish verified that the fungal colonization might be influenced by their surrounding environments. Furthermore, the fungal communities in different intestines of some fish were significantly different, and the number of yeasts in the hindgut was less than that in fore- and mid-intestines, suggesting that the distribution of fungi in fishes' intestines may be related to the physiological functions of various intestinal segments. In addition, 51.4% of tested fungal isolates exhibited antimicrobial activity against at least one marine pathogenic microorganism. Notably, isolate Aureobasidium pullulans SCAU243 exhibited strong antifungal activity against Aspergillus versicolor, and isolate Schizophyllum commune SCAU255 displayed extensive antimicrobial activity against four marine pathogenic microorganisms. This study contributed to our understanding of intestinal fungi in coral reef fish and further increased the library of fungi available for natural bioactive product screening.

Coral reef fish communities of natural habitats and man-made coastal structures in Bora-Bora (French Polynesia)

Coastal habitats have long been recognised to be nurseries and growing grounds for many marine organisms. Worldwide, coastal hardening and urbanisation are leading to the removal of natural ecosystems. The tropical island of Bora-Bora in the South Pacific has undergone extensive coastal changes, with the construction of seawalls along more than half of its coastline since the 1950s. The daytime and night-time juvenile and adult fish communities were surveyed with multiple temporal replicates on a range of lagoon and coastal habitats on Bora-Bora. Over 47% of all fish on coastal habitats were juveniles. Mangroves, traditionally viewed as nurseries, had a high daytime and night-time abundance of juveniles, but less than 1% of the coastline of Bora-Bora consists of mangroves. The manmade seawalls, which are the most common type of coastal habitat on the island, were associated with lower juvenile densities during the day and promoted the presence of predators. The comparison of coastal and lagoon sites also highlighted contrasting life history strategies depending on coral reef fish species: although many favour coastal habitats as juveniles, others do not undergo ontogenetic shifts and thus other habitats must be considered when designing management plans to protect juvenile fish. Overall, our surveys show the importance of natural coastal zones in the lifecycle of numerous coral reef fish species in the lagoon of Bora-Bora and highlight the potential long-term impacts of coastal hardening on fish communities.

Chromosome-level genome of the three-spot damselfish, Dascyllus trimaculatus.

Damselfishes (Family: Pomacentridae) are a group of ecologically important, primarily coral reef fishes that include over 400 species. Damselfishes have been used as model organisms to study recruitment (anemonefishes), the effects of ocean acidification (spiny damselfish), population structure, and speciation (Dascyllus). The genus Dascyllus includes a group of small-bodied species, and a complex of relatively larger bodied species, the Dascyllus trimaculatus species complex that is comprised of several species including D. trimaculatus itself. The three-spot damselfish, D. trimaculatus, is a widespread and common coral reef fish species found across the tropical Indo-Pacific. Here, we present the first-genome assembly of this species. This assembly contains 910 Mb, 90% of the bases are in 24 chromosome-scale scaffolds, and the Benchmarking Universal Single-Copy Orthologs score of the assembly is 97.9%. Our findings confirm previous reports of a karyotype of 2n = 47 in D. trimaculatus in which one parent contributes 24 chromosomes and the other 23. We find evidence that this karyotype is the result of a heterozygous Robertsonian fusion. We also find that the D. trimaculatus chromosomes are each homologous with single chromosomes of the closely related clownfish species, Amphiprion percula. This assembly will be a valuable resource in the population genomics and conservation of Damselfishes, and continued studies of the karyotypic diversity in this clade.

Modelling and forecasting the effects of increasing sea surface temperature on coral bleaching in the Indo-Pacific region

ABSTRACT The Coral Triangle (CT) and the South China Sea (SCS) are the world’s great tropical seas, located in the Indo-Pacific (IP) region. It is home to the richest marine ecosystem on Earth, with a total of 76% reef-building coral species as well as 37% coral reef fish species. Unfortunately, this sensitive area is now vulnerable to Sea Surface Temperature (SST) warming. This research explored the possible consequences of SST warming on the rich ecosystems of the IP region, specifically on bleaching of its coral reefs. Reefbase provided coral bleaching records together with the daily NOAA AVHRR Optimum Interpolation (OI) SST V2 dataset (OISSTv2) were used to explore the relationship between coral bleaching and SST in the IP region. Three different categories of monthly mean SST were tested as potential covariates: minimum SST, mean SST and maximum SST, obtained from the OISSTv2. The fitted logistic regression (LR) model revealed a significant and large correlation between coral bleaching and annual maximum monthly mean SST in the study area using the bleaching data from an online database and the time-series of AVHRR images. Predicted maps of coral bleaching based on the LR model were highly consistent with NOAA Coral Reef Watch (CRW) Degree heating Weeks (DHW) maps. However, some important discrepancies resulted from the more specific local fitting used in the LR model. The maximum SST was forecasted from 2020 to 2100 based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) dataset under the Representative Concentration Pathways (RCP2.6) scenario. The fitted logistic regression model was employed to transform the forecasted maximum SST values into maps of the probability of coral bleaching from 2020 to 2100. The results provide considerable cause for concern, including the likelihood of widespread coral bleaching in many places in the IP region over the next 30 years.

Differences in the behavior and diet between shoaling and solitary surgeonfish (Acanthurus triostegus).

Variation in behavior within marine and terrestrial species can influence the functioning of the ecosystems they inhabit. However, the contribution of social behavior to ecosystem function remains underexplored. Many coral reef fish species provide potentially insightful models for exploring how social behavior shapes ecological function because they exhibit radical intraspecific variation in sociality within a shared habitat. Here, we provide an empirical exploration on how the ecological function of a shoaling surgeonfish (Acanthurus triostegus) may differ from that of solitary conspecifics on two Pacific coral reefs combining insight from behavioral observations, stable isotope analysis, and macronutrient analysis of gut and fecal matter. We detected important differences in how the social mode of A.triostegus affected its spatial and feeding ecology, as well as that of other reef fish species. Specifically, we found increased distance traveled and area covered by shoaling fish relative to solitary A.triostegus. Additionally, shoaling A.triostegus primarily grazed within territories of other herbivorous fish and had piscivorous and nonpiscivorous heterospecific fish associated with the shoal, while solitary A.triostegus grazed largely grazed outside of any territories and did not have any such interactions with heterospecific fish. Results from stable isotope analysis show a difference in δ15N isotopes between shoaling and solitary fish, which suggests that these different social modes are persistent. Further, we found a strong interaction between social behavior and site and carbohydrate and protein percentages in the macronutrient analysis, indicating that these differences in sociality are associated with measurable differences in both the feeding ecology and nutrient excretion patterns. Our study suggests that the social behavior of individuals may play an important and underappreciated role in mediating their ecological function.