Coral Reef Fish Families Research Articles

Long-wavelength-sensitive (lws) opsin gene expression, foraging and visual communication in coral reef fishes.

Coral reef fishes are diverse in ecology and behaviour and show remarkable colour variability. Investigating the visual pigment gene (opsin) expression in these fishes makes it possible to associate their visual genotype and phenotype (spectral sensitivities) to visual tasks, such as feeding strategy or conspecific detection. By studying all major damselfish clades (Pomacentridae) and representatives from five other coral reef fish families, we show that the long-wavelength-sensitive (lws) opsin is highly expressed in algivorous and less or not expressed in zooplanktivorous species. Lws is also upregulated in species with orange/red colours (reflectance >520 nm) and expression is highest in orange/red-coloured algivores. Visual models from the perspective of a typical damselfish indicate that sensitivity to longer wavelengths does enhance the ability to detect the red to far-red component of algae and orange/red-coloured conspecifics, possibly enabling social signalling. Character state reconstructions indicate that in the early evolutionary history of damselfishes, there was no lws expression and no orange/red coloration. Omnivory was most often the dominant state. Although herbivory was sometimes dominant, zooplanktivory was never dominant. Sensitivity to long wavelength (increased lws expression) only emerged in association with algivory but never with zooplanktivory. Higher lws expression is also exploited by social signalling in orange/red, which emerged after the transition to algivory. Although the relative timing of traits may deviate by different reconstructions and alternative explanations are possible, our results are consistent with sensory bias whereby social signals evolve as a correlated response to natural selection on sensory system properties in other contexts.

Ear Development in Select Coral Reef Fishes: Clues for the Role of Hearing in Larval Orientation Behavior?

The pelagic larvae of coral reef fishes can detect and discriminate among different types of sounds suggesting that they may be able to localize acoustic cues and thus identify suitable settlement sites on reefs. It has been suggested that a description of ear development may provide clues about the importance of sound in larval behavior. Here we provide the first description of the ontogeny of the ear in the pelagic larvae and juveniles of representatives of three important families of coral reef fishes: Gobiidae (Elacatinus lori, E. colini), Apogonidae (Cheilodipterus quinquelineatus), and Pomacentridae (Amblyglyphidodon leucogaster, Amphiprion polymnus). Histological analysis revealed that the ear of the larvae and juveniles of the five study species lack any of the morphological specializations known in percomorph fishes. However, it showed that the ears of the two gobies are quite similar with respect to size and shape of the three otolithic organs, but that ears of the cardinalfish and damselfishes are different with respect to the absolute and relative sizes and position of the otolithic organs, as well as the timing of the appearance of the lagena; however, the functional significance of these features are unknown. It is concluded that if hearing plays a role in orientation behavior in the pelagic larvae of coral reef fishes then their “unremarkable” ears are sufficient to allow these diminutive fishes to carry out the extraordinary feat of navigating the open ocean and successfully locating coral reefs on which to settle.

Do currents shape global patterns of hybrid richness in coral reef fishes?

AbstractAimOur main aim was to identify the distribution of, and potential mechanisms underpinning, hybrid‐rich zones – regions with a disproportionate number of unique interspecific hybrids. We investigated whether coral reef fish hybrids coincided with factors such as phylogenetic relatedness, biogeographic barriers, species richness, geographic isolation, endemism, and oceanic currents.LocationGlobal.Time periodContemporary.Major taxa studiedCoral reef fishes.MethodsWe conducted a literature review and mapping to assess the taxonomic and global prevalence of hybridisation in coral reef fishes. We then fit Generalised additive models using a full‐subsets and Bayesian framework to assess which variables are associated with hybrid‐rich zones.ResultsWe found 143 unique interspecific coral reef fish hybrids involving 204 species – which accounts for approximately 7% of coral reef fish species, indicating that hybridisation is as common in the sea as it is on land. Characteristic coral reef fish families were not homogeneously represented in our dataset, with particularly colourful groups standing out. Mapping our dataset revealed that coral reef fish hybrids are found worldwide, though some ecoregions (e.g., the Christmas and Cocos (Keeling) Islands, South Kuroshio, Hawaii, and Eastern Philippines) are more hybrid‐rich than others. Our analysis revealed that mean surface current velocity, phylogenetic relatedness, and geographic isolation were the best predictors of hybrid richness in a given location.Main conclusionsPhylogenetic distance between coral reef fish species may serve as a pre‐condition for hybridisation to occur, lying between introgression and reproductive incompatibility. We also propose a novel mechanism, with oceanic currents driving long‐distance larval dispersal events, transporting stray species to geographically remote sinks to maintain hybrid‐rich zones.

Development of dim-light vision in the nocturnal reef fish family Holocentridae. II: Retinal morphology.

ABSTRACTOntogenetic changes in the habitats and lifestyles of animals are often reflected in their visual systems. Coral reef fishes start life in the shallow open ocean but inhabit the reef as juveniles and adults. Alongside this change in habitat, some species also change lifestyles and become nocturnal. However, it is not fully understood how the visual systems of nocturnal reef fishes develop and adapt to these significant ecological shifts over their lives. Therefore, we used a histological approach to examine visual development in the nocturnal coral reef fish family, Holocentridae. We examined 7 representative species spanning both subfamilies, Holocentrinae (squirrelfishes) and Myripristinae (soldierfishes). Pre-settlement larvae showed strong adaptation for photopic vision with high cone densities and had also started to develop a multibank retina (i.e. multiple rod layers), with up to two rod banks present. At reef settlement, holocentrids showed greater adaptation for scotopic vision, with higher rod densities and higher summation of rods onto the ganglion cell layer. By adulthood, they had well-developed scotopic vision with a highly rod-dominated multibank retina comprising 5–17 rod banks and enhanced summation of rods onto the ganglion cell layer. Although the ecological demands of the two subfamilies were similar throughout their lives, their visual systems differed after settlement, with Myripristinae showing more pronounced adaptation for scotopic vision than Holocentrinae. Thus, it is likely that both ecology and phylogeny contribute to the development of the holocentrid visual system.

Development of dim-light vision in the nocturnal reef fish family Holocentridae. I: Retinal gene expression.

ABSTRACTDevelopmental changes to the visual systems of animals are often associated with ecological shifts. Reef fishes experience a change in habitat between larval life in the shallow open ocean to juvenile and adult life on the reef. Some species also change their lifestyle over this period and become nocturnal. While these ecological transitions are well documented, little is known about the ontogeny of nocturnal reef fish vision. Here, we used transcriptomics to investigate visual development in 12 representative species from both subfamilies, Holocentrinae (squirrelfishes) and Myripristinae (soldierfishes), in the nocturnal coral reef fish family, Holocentridae. Results revealed that the visual systems of holocentrids are initially well adapted to photopic conditions with pre-settlement larvae having high levels of cone opsin gene expression and a broad cone opsin gene repertoire (8 genes). At reef settlement, holocentrids started to invest more in their scotopic visual system, and compared with adults, showed upregulation of genes involved in cell differentiation/proliferation. By adulthood, holocentrids had well developed scotopic vision with high levels of rod opsin gene expression, reduced cone opsin gene expression and repertoire (1–4 genes) and upregulated phototransduction genes. Finally, although the two subfamilies shared similar ecologies across development, their visual systems diverged after settlement, with Myripristinae investing more in scotopic vision than Holocentrinae. Hence, both ecology and phylogeny are likely to determine the development of the holocentrid visual system.

Marine Biodiversity of Coral Reef Fishes in Pieh Marine Recreational Park After Bleaching and Acanthaster Outbreaks

Highlight ResearchAfter bleaching disturbance and Acanthaster planci outbreaks, herbivore fishes species were dominated in MRP PiehThis explains the marine recreational activities in utilization zone MRP Pieh have no impact on reducing fish biomassAfter disturbance in MRP Pieh shows the coral reef fishes still endurance on bleaching event, and Acanthaster planci outbreak after disturbance in MRP Pieh shows the coral reef fishes still endurance on bleaching event and Acanthaster planci outbreak. However, the composition of corallivorous has decreased but has been an increase in herbivorous and carnivorous fish populationsAbstractPieh MRP encountered non-anthropogenic phenomena, precisely massive coral bleaching in 2016, 2017, and massive predators from Acanthaster planci outbreaks in 2018. This study aimed to understand the pattern of coral reef diversity in the core zone and utilization in the MRP area and compare it to non-MRPS locations that accept the same non-anthropogenic pressure conditions. Coral fish sampling using a UVC is categorized into three zones: the core zone, the utilization zone, and outside the MRP area. 8 Families of coral reef fishes were counted based on categories of level function in ecologies and economy. Taxonomic distinctiveness estimates were calculated mathematically for each sample, including species richness and taxonomic diversity were compared among zonation area. Pearson’s Coefficient Correlation Matrix was used to measure the correlation relationship between zonation areas. There are 91 species of fish and 3002 individuals found. The richest family in the MRP Core Zone and MRP Utility Zone was Acanthuridae with 20 species and non-MRP has a lower species richness and abundance of fish communities. The dominant species in Pieh MRP was Ctenochaetus striatus with average abundant per site (21.3 ± 7.62, n = 3). Acanthuridae represents 55.98% of the total biomass in MRP-Core Zone, 63.13% in MRP-Utility Zone, and 41.55% in Non-MRP Area. This study showed the number of species and populations from corallivores fishes have decreased but has been an increase in herbivorous and carnivore diversity. The diversity indices (H’) and ENS also shows no differ significantly between zonation.

Coral reef fishes in the coastal waters of Ninh Thuan province

This study was conducted to evaluate the species composition and distribution of coral reef fish communities at 24 sites in three areas Ninh Hai, Phuoc Dinh, and Ca Na in Ninh Thuan province from 2018 to 2019. A total of 301 species belonging to 131 genera and 49 families of coral reef fishes were recorded. Among them, the wrasse (Labridae: 55 species), the damselfish (Pomacentridae: 46 species) and the butterflyfish (Chaetodontidae: 26 species) occupy the three highest proportion. The average density of coral reef fish in coastal waters of Ninh Thuan province is 106.8 ± 23.4 individuals/100 m2, most of them are small sized fish and ornamental fish groups. Ninh Hai has a higher species richness and density than other areas. Meanwhile, Ca Na and Phuoc Dinh have the two highest densities of the large sized fish and food target fish groups. This research also points out the impact of monsoon on the density and distribution of coral reef fish, in which Ninh Hai is most affected.

Abundance, diversity, and distribution of coral reef fish families in the Egyptian Red Sea, at Hurghada, Egypt

Abundance, diversity, and distribution of coral reef fish families in the Egyptian Red Sea, at Hurghada, Egypt

Tropical marine fish from Celukan Bawang Port, Buleleng, Bali, Indonesia

Celukan Bawang port is located in Buleleng Regency, Bali, Indonesia. The area of Celukan Bawang Port has a coral reef ecosystem that is very rarely found in Indonesian ports. The coral reef has an important role for coral reef fish as their habitat. This study aims to conduct coral reef fish in the Celukan Bawang port area. A survey was conducted by using UVC (Underwater Visual Census) method at four (4) stations in October 2019. The coral-reef fish family identified in this research consisted of 853 individuals belonging to 14 families and 34 species. The dominant family were Pomacentridae (63.53%), Labridae (25.21%), Achanthuridae (2.70%), Chaetodontidae (1.17%), and Ptereleotrididae (1.17%). The most abundant species were Dascyllus trimaculatus (2270 ind/ha), Halichoeres prosopeion (1550 ind/ha), and Pomacentrus coelestis (95 ind/ha). Shannon-Wiener diversity index value was 2.414, and there were no dominant species observed.

The visual ecology of Holocentridae, a nocturnal coral reef fish family with a deep-sea-like multibank retina.

The visual systems of teleost fishes usually match their habitats and lifestyles. Since coral reefs are bright and colourful environments, the visual systems of their diurnal inhabitants have been more extensively studied than those of nocturnal species. In order to fill this knowledge gap, we conducted a detailed investigation of the visual system of the nocturnal reef fish family Holocentridae. Results showed that the visual system of holocentrids is well adapted to their nocturnal lifestyle with a rod-dominated retina. Surprisingly, rods in all species were arranged into 6-17 well-defined banks, a feature most commonly found in deep-sea fishes, that may increase the light sensitivity of the eye and/or allow colour discrimination in dim light. Holocentrids also have the potential for dichromatic colour vision during the day with the presence of at least two spectrally different cone types: single cones expressing the blue-sensitive SWS2A gene, and double cones expressing one or two green-sensitive RH2 genes. Some differences were observed between the two subfamilies, with Holocentrinae (squirrelfish) having a slightly more developed photopic visual system than Myripristinae (soldierfish). Moreover, retinal topography of both ganglion cells and cone photoreceptors showed specific patterns for each cell type, likely highlighting different visual demands at different times of the day, such as feeding. Overall, their well-developed scotopic visual systems and the ease of catching and maintaining holocentrids in aquaria, make them ideal models to investigate teleost dim-light vision and more particularly shed light on the function of the multibank retina and its potential for dim-light colour vision.

An updated checklist of the marine fish fauna of Redang Islands, Malaysia.

BackgroundRedang Islands Marine Park consists of nine islands in the state of Terengganu, Malaysia. Redang Island is one of the largest off the east coast of Peninsular Malaysia, which is famous for its crystal-clear waters and white sandy beaches. The ichthyofauna of the Redang archipelago was surveyed by underwater visual observations between August 2016 and May 2018. Census data were compiled with existing records into the checklist of the marine fish of the Redang archipelago presented herein. A total of 314 species belonging to 51 families were recorded. The most speciose families (Pomacentridae, Labridae, Scaridae, Serranidae, Apogonidae, Carangidae, Gobiidae, Chaetodontidae, Lutjanidae, Nemipteridae and Siganidae) were also amongst the most speciose at the neighbouring Tioman archipelago (except Chaetodontidae). The coral fish diversity index value for the six families of coral reef fishes (Chaetodontidae, Pomacanthidae, Pomacentridae, Labridae, Scaridae and Acanthuridae) of the study sites was 132. We estimated that there were 427 coral reef fish species in the Redang archipelago. According to the IUCN Red List, eight species are Near Threatened (Carcharhinus melanopterus, Chaetodon trifascialis, Choerodon schoenleinii, Epinephelus fuscoguttatus, E. polyphekadion, Plectropomus leopardus, Taeniura lymma and Triaenodon obesus), eleven are Vulnerable (Bolbometopon muricatum, Chaetodon trifasciatus, Chlorurus sordidus, Dascyllus trimaculatus, Epinephelus fuscoguttatus, E. polyphekadion, Halichoeres marginatus, Heniochus acuminatus, Nebrius ferrugineus, Neopomacentrus cyanomos and Plectropomus areolatus) and three are Endangered (Amphiprion clarkia, Cheilinus undulatus and Scarus ghobban) in the Redang archipelago.New informationFive species are new records for Malaysia (Ctenogobiops mitodes, Epibulus brevis, Halichoeres erdmanni, H. richmondi and Scarus caudofasciatus) and 25 species are newly recorded in the Redang archipelago.

Reproductive characteristics of coral-reef fishes, Pomacentridae, Monodactylidae and Chaetodontidae, in the east coast of Peninsula Malaysia

In order to understand the reproductive ecology of coral-reef fishes, fecundity which is the physiological maximum potential reproductive output, was examined in eleven families of coral-reef fishes in the east coast of Peninsula Malaysia. Three families, Pomacentridae, Monodactylidae and Chaetodontidae, with five species, Amphiprion ocellaris, Amphiprion perideraion, Abudefduf bengalensis, Monodactylus argenteus and Chaetodon octofasciatus, could collect female specimens, while all specimens were male in eight out of eleven families with sixteen species. Mean fecundities ranged from 693 to 122,247 with the lowest fecundity was found in Pomacentridae, and Chaetodontidae had the highest fecundity. Amphiprion ocellaris and A. perideraion practice parental care with demersal spawners, and such unique reproductive ecology might produce lower number of eggs to be able to increase their reproductive success compared to other coral reef fishes spawned pelagic eggs. This study provides an insight of baseline knowledge of the reproductive biology of coral-reef fishes for future studies of important fish species in coral ecosystem.

Coral reef fishes in the banks and rocky islands in the offshore waters of Binh Thuan province

Binh Thuan province is located in the South Central Coast of Vietnam with favorable conditions for living coral reefs. The coral reefs were mainly investigated in coastal water areas and Phu Quy island, meanwhile other areas such as the banks and rocky islands seem to lack information. This study was conducted to evaluate the species composition and distribution of coral reef fish communities in the Royal Bishop banks and around rocky islands in Julia shoal in the offshore waters of Binh Thuan province in April 2019. A total of 151 species belonging to 86 genera and 33 families of coral reef fishes were recorded. Among them, 4 species for the first time recorded in Vietnam are Helcogramma striata (Hansen, 1986) (Tripterygiidae), Pseudanthias squamipinnis (Peters, 1855) (Serranidae), Bodianus bilunulatus (Lacepède, 1801) and Coris aygula (Lacepède, 1801) (Labridae). The total average density of coral reef fish in the offshore waters of Binh Thuan is quite high at 1,104.9 ± 617 individuals/250 m2, most of them are small sized fish and ornamental fish group, the large sized fish and target fish group accounts for a relatively low rate, but their density here is much higher compared to that in the coastal waters of Binh Thuan province. The comparative analysis also shows that sites in coral reef around rocky islands have species richness and density of coral reef fish higher than the bank area.

Distribution of fish larvae within a weakly tidal mangrove lagoon

Mangroves have been shown to provide valuable nursery grounds to juvenile fishes, yet little is known regarding larval distribution and settlement processes in this habitat. To investigate fish larvae in mangrove habitat in a semi-isolated lagoon (surface area 750m2), we employed multiple catch methods: plankton tows, minnow traps, and light traps during June–August 2008 and 2009. Overall, nine families of fish larvae were caught in the light traps. Light traps caught significantly more fish larvae during the new moon compared with the full moon. Plankton tow nets caught early-stage, unidentifiable (without DNA analysis) larvae. Minnow traps only caught a total of three fish larvae. Overall, scarids (parrotfish) and lutjanids (snappers) were the most common larvae from coral-reef fish families and were found at sites over 1km upstream of the mouth of the mangrove lagoon. Without the aid of tidal influence (and nets requiring hydrodynamic force), sampling is difficult in these turbid, shallow waters.

Community assemblages of commercially important coral reef fishes inside and outside marine protected areas in the Philippines

Establishment of marine protected areas (MPA) is among the most commonly implemented initiatives for coral reef conservation and fisheries management in the Philippines. However, there are concerns that the MPAs in the country may not work because of their generally small sizes and high fishing pressures from the burgeoning highly resource-dependent population. In this study, we assessed the assemblages of seven commercially important coral reef fish families (Acanthuridae (excluding genus Zebrasoma), Labridae (subfamily Scarinae only), Lutjanidae, Serranidae (subfamily Epinephelinae only), Mullidae, Haemulidae and Lethrinidae) inside and outside MPAs in 37 coastal municipalities in the Philippines. A total of 12,354 individuals belonging to 114 species (33 species of Acanthuridae, 27 species of Scarinae, 17 species of Lutjanidae, 16 species of Epinephelinae, 9 species of Mullidae, 6 species of Haemulidae, and 6 species of Lethrinidae) were recorded. Overall, reef fishes inside MPAs were more diverse than outside MPAs based on Shannon–Wiener index of diversity. Reefs inside MPAs had an average of four more fish species than outside MPAs. Both inside and outside MPAs had comparable equitability values which are characterized by fish communities that are largely dominated by few species only. Higher fish densities, especially fishes with ⩾25cm (total length), were also recorded inside MPAs. However, we also found some patterns suggesting that more efforts must be made in order to effectively protect many of the commercially important coral reef fishes from the impacts of fishing. Our study provides valuable science-based insights that can be used to improve coral reef conservation and fisheries management initiatives in the country. Moreover, it can also serve as crucial information that can be used for monitoring and evaluation of MPA effectiveness, particularly on commercially important coral reef fishes in the country.

On the relationship between species age and geographical range in reef fishes: are widespread species older than they seem?

AbstractAimIn order to better understand processes of speciation, range‐size transformation and extinction, macroecological studies seek to identify the evolutionary dynamics of species geographical ranges. This requires accurate estimates of range size and species age. Species ages are attainable through recent success with techniques to estimate phylogenetic divergence time. Conceptual synthesis of the inherent problems with these techniques has been limited. Our aim is to address the effects of estimation of phylogenetic divergence time on the relationship between species age and geographical range.InnovationCommonly, estimates of divergence time from the nodes of a time‐calibrated phylogeny are used as indicators of ages of extant species. However, this method can sometimes produce misleading age estimates, specifically in the presence of extinction and ancestral persistence. An example of this is illustrated using a comprehensive genetic dataset of genera with near‐complete sampling of species from four of the major coral reef fish families. We present a method to minimize the impacts of extinction and ancestral persistence on divergence time estimation. The method focuses on recent divergences and involves pairing minimum divergence time estimates (as indicators of species ages) with the minimum geographical range area between two sister‐species, for all sister‐species pairs.Main conclusionsWhen applied to coral reef fishes, this method revealed trends in the relationship between species age and geographical range. The difference in the trend recovered from excluding potential biases associated with ancestral persistence suggests that ancestral persistence may be prevalent among coral reef fishes, with successive peripheral speciation affecting area–age relationships. The method may reveal the occurrence of successive peripheral speciation events across a broad range of taxa.

Local fishing influences coral reef fish behavior inside protected areas of the Indo-Pacific

Fishing is altering aquatic ecosystems through changes in the abundance, species composition and behavior of target species. Changes in fish behavior have received relatively little attention, despite significant evidence of behavioral change driven by human impacts mediating function and processes in terrestrial ecosystems, and emerging evidence that the same is true in marine systems even within marine reserves. Here, we measured the wariness of two families of coral reef fishes in both fished areas and marine reserves embedded within a fished seascape along an exploitation gradient ranging from wilderness sites (Chagos) to heavily fished areas (the Philippines). We used linear mixed effect models to identify relationships between fish flight initiation distance (FID) and fishing pressure, fish size, habitat complexity and life-history stage. Critically, fish FID increased with fishing pressure both in fished areas and inside marine reserves. These results imply that as fishing pressure increases in adjacent areas, progressively greater fish wariness may reduce the magnitude of some ecosystem functions within small marine reserves.

Larval dispersal and movement patterns of coral reef fishes, and implications for marine reserve network design.

Well-designed and effectively managed networks of marine reserves can be effective tools for both fisheries management and biodiversity conservation. Connectivity, the demographic linking of local populations through the dispersal of individuals as larvae, juveniles or adults, is a key ecological factor to consider in marine reserve design, since it has important implications for the persistence of metapopulations and their recovery from disturbance. For marine reserves to protect biodiversity and enhance populations of species in fished areas, they must be able to sustain focal species (particularly fishery species) within their boundaries, and be spaced such that they can function as mutually replenishing networks whilst providing recruitment subsidies to fished areas. Thus the configuration (size, spacing and location) of individual reserves within a network should be informed by larval dispersal and movement patterns of the species for which protection is required. In the past, empirical data regarding larval dispersal and movement patterns of adults and juveniles of many tropical marine species have been unavailable or inaccessible to practitioners responsible for marine reserve design. Recent empirical studies using new technologies have also provided fresh insights into movement patterns of many species and redefined our understanding of connectivity among populations through larval dispersal. Our review of movement patterns of 34 families (210 species) of coral reef fishes demonstrates that movement patterns (home ranges, ontogenetic shifts and spawning migrations) vary among and within species, and are influenced by a range of factors (e.g. size, sex, behaviour, density, habitat characteristics, season, tide and time of day). Some species move <0.1-0.5 km (e.g. damselfishes, butterflyfishes and angelfishes), <0.5-3 km (e.g. most parrotfishes, goatfishes and surgeonfishes) or 3-10 km (e.g. large parrotfishes and wrasses), while others move tens to hundreds (e.g. some groupers, emperors, snappers and jacks) or thousands of kilometres (e.g. some sharks and tuna). Larval dispersal distances tend to be <5-15 km, and self-recruitment is common. Synthesising this information allows us, for the first time, to provide species, specific advice on the size, spacing and location of marine reserves in tropical marine ecosystems to maximise benefits for conservation and fisheries management for a range of taxa. We recommend that: (i) marine reserves should be more than twice the size of the home range of focal species (in all directions), thus marine reserves of various sizes will be required depending on which species require protection, how far they move, and if other effective protection is in place outside reserves; (ii) reserve spacing should be <15 km, with smaller reserves spaced more closely; and (iii) marine reserves should include habitats that are critical to the life history of focal species (e.g. home ranges, nursery grounds, migration corridors and spawning aggregations), and be located to accommodate movement patterns among these. We also provide practical advice for practitioners on how to use this information to design, evaluate and monitor the effectiveness of marine reserve networks within broader ecological, socioeconomic and management contexts.

Temporal evolution of coral reef fishes: global patterns and disparity in isolated locations

AbstractAimMany coral reef regions have a history of isolation and extinction. Our aim was to test whether the disparate evolutionary and biogeographical histories of the world's coral reef regions have significantly impacted temporal patterns of speciation within regions. In essence, do assemblages in peripheral locations contain the youngest coral reef fish species?LocationPan‐tropical coral reef systems.MethodsMolecular data (mitochondrial 16S rRNA, 12S rRNA, CO1, cytochrome b; nuclear TMO‐4C4, S7 intron 1) were assembled for genera with near‐complete taxon sampling (minimum 70% nominal species) from four major coral reef fish families (Chaetodontidae, Labridae, Pomacanthidae and Serranidae). This was combined with fossil data to simultaneously infer the phylogeny and estimate species' divergence times. species' distributions were quantified using IUCN maps and the ages of species with different biogeographical extents were compared. Model fitting was used to compare the distribution of species' ages across the whole phylogeny with age distributions of species restricted to the Red Sea and Hawaiian Islands.ResultsTemporal patterns of coral reef fish divergence were similar among major marine realms and regions. However, notable differences were recorded between the Red Sea and Hawaiian Islands. Red Sea endemics have diverged consistently throughout the last 16 Myr, whereas endemic species colonized the Hawaiian Islands in two distinct waves (0–3 Ma and 8–12 Ma). Differences in the proportions of allopatric and sympatric sister‐species between Red Sea and Hawaiian endemics were also detected.Main conclusionsDespite differing geological histories, marine realms and regions have all experienced comparable and relatively recent divergences of extant coral reef fish species. Differences in age distributions and spatial relationships of endemic species in the Red Sea and Hawaiian Islands suggest that markedly different processes have shaped patterns of diversification in these peripherally isolated locations.

Sargo Amarelo, a traditionally recognized hybrid between two species of Brazilian reef fishes

Hybridization has been described in several families ofcoral reef fishes (Montanari et al. 2012), including grunts(genus Haemulon) (Rocha et al. 2008). Here, we report thepresence of a hybrid between two species of Anisotremusgrunts, the porkfish, A. virginicus, and the black margate, A.surinamensis, from Cabo Frio, Rio de Janeiro (23°S, 42°W).Interestingly, A. virginicus and A. surinamensis are notsister species (Bernardi et al. 2008), but both are commonin that region.On 1 December 2012, while collecting fish tissues formolecular studies at a local spearfishing tournament, weobserved one individual that showed typical morphologicaland coloration characteristics of both A. virginicus (goldlines along the body), and A. surinamensis (large bronzebody). DNA sequencing of that individual following pub-lished protocols (Tavera et al. 2012) showed that the mito-chondrial cytochrome oxydase 1 (CO1) was identical to A.virginicus, and the nuclear RAG2 gene displayed heterozy-gous peaks at all 6 fixed nucleotide positions that differbetween A. virginicus and A. surinamensis (Fig. 1)(GenBankaccessionnumbersKC844035–KC844036).The-se results are consistent with an F1 cross between these twospecies, with A. virginicus as a maternal lineage and thepresence of A. surinamensis in its paternal ancestry. Suchhybrids are not uncommon in the subtropical reefs of thesoutheasternregionofBrazil,wherefishermenrecognizethefish as a hybrid by its local name Sargo Amarelo ("yellowgrunt").