Coral Reef Fish Families Research Articles

A new versatile primer set targeting a short fragment of the mitochondrial COI region for metabarcoding metazoan diversity: application for characterizing coral reef fish gut contents

IntroductionThe PCR-based analysis of homologous genes has become one of the most powerful approaches for species detection and identification, particularly with the recent availability of Next Generation Sequencing platforms (NGS) making it possible to identify species composition from a broad range of environmental samples. Identifying species from these samples relies on the ability to match sequences with reference barcodes for taxonomic identification. Unfortunately, most studies of environmental samples have targeted ribosomal markers, despite the fact that the mitochondrial Cytochrome c Oxidase subunit I gene (COI) is by far the most widely available sequence region in public reference libraries. This is largely because the available versatile (“universal”) COI primers target the 658 barcoding region, whose size is considered too large for many NGS applications. Moreover, traditional barcoding primers are known to be poorly conserved across some taxonomic groups.ResultsWe first design a new PCR primer within the highly variable mitochondrial COI region, the “mlCOIintF” primer. We then show that this newly designed forward primer combined with the “jgHCO2198” reverse primer to target a 313 bp fragment performs well across metazoan diversity, with higher success rates than versatile primer sets traditionally used for DNA barcoding (i.e. LCO1490/HCO2198). Finally, we demonstrate how the shorter COI fragment coupled with an efficient bioinformatics pipeline can be used to characterize species diversity from environmental samples by pyrosequencing. We examine the gut contents of three species of planktivorous and benthivorous coral reef fish (family: Apogonidae and Holocentridae). After the removal of dubious COI sequences, we obtained a total of 334 prey Operational Taxonomic Units (OTUs) belonging to 14 phyla from 16 fish guts. Of these, 52.5% matched a reference barcode (>98% sequence similarity) and an additional 32% could be assigned to a higher taxonomic level using Bayesian assignment.ConclusionsThe molecular analysis of gut contents targeting the 313 COI fragment using the newly designed mlCOIintF primer in combination with the jgHCO2198 primer offers enormous promise for metazoan metabarcoding studies. We believe that this primer set will be a valuable asset for a range of applications from large-scale biodiversity assessments to food web studies.

Chemical alarm cues are conserved within the coral reef fish family Pomacentridae.

Fishes are known to use chemical alarm cues from both conspecifics and heterospecifics to assess local predation risks and enhance predator detection. Yet it is unknown how recognition of heterospecific cues arises for coral reef fishes. Here, we test if naïve juvenile fish have an innate recognition of heterospecific alarm cues. We also examine if there is a relationship between the intensity of the antipredator response to these cues and the degree to which species are related to each other. Naïve juvenile anemone fish, Amphiprion percula, were tested to see if they displayed antipredator responses to chemical alarm cues from four closely related heterospecific species (family Pomacentridae), a distantly related sympatric species (Asterropteryx semipunctatus) and a saltwater (control). Juveniles displayed significant reductions in foraging rate when exposed to all four confamilial heterospecific species but they did not respond to the distantly related sympatric species or the saltwater control. There was also a strong relationship between the intensity of the antipredator response and the extent to which species were related, with responses weakening as species became more distantly related. These findings demonstrate that chemical alarm cues are conserved within the pomacentrid family, providing juveniles with an innate recognition of heterospecific alarm cues as predicted by the phylogenetic relatedness hypothesis.

Specializing on vulnerable habitat: Acropora selectivity among damselfish recruits and the risk of bleaching-induced habitat loss

Coral reef habitats are increasingly being degraded and destroyed by a range of disturbances, most notably climate-induced coral bleaching. Habitat specialists, particularly those associated with susceptible coral species, are clearly among the most vulnerable to population decline or extinction. However, the degree of specialization on coral microhabitats is still unclear for one of the most ubiquitous, abundant and well studied of coral reef fish families—the damselfishes (Pomacentridae). Using high taxonomic resolution surveys of microhabitat use and availability, this study provides the first species-level description of patterns of Acropora selectivity among recruits of 10 damselfish species in order to determine their vulnerability to habitat degradation. In addition, surveys of the bleaching susceptibility of 16 branching coral species revealed which preferred recruitment microhabitats are at highest risk of decline as a result of chronic coral bleaching. Four species (i.e., Chrysiptera parasema, Pomacentrus moluccensis, Dascyllus melanurus and Chromis retrofasciata) were identified as highly vulnerable because they used only branching hard corals as recruitment habitat and primarily associated with only 2–4 coral species. The bleaching surveys revealed that five species of Acropora were highly susceptible to bleaching, with more than 50% of colonies either severely bleached or already dead. These highly susceptible corals included two of the preferred microhabitats of the specialist C. parasema and represented a significant proportion of its total recruitment microhabitat. In contrast, highly susceptible corals were rarely used by another specialist, P. moluccensis, suggesting that this species faces a lower risk of bleaching-induced habitat loss compared to C. parasema. As degradation to coral reef habitats continues, specialists will increasingly be forced to use alternative recruitment microhabitats, and this is likely to reduce population replenishment. Future research should focus on examining the fitness costs of using these alternative microhabitats.

Reconciling molecules and morphology: Molecular systematics and biogeography of Neotropical blennies (Acanthemblemaria)

Neotropical reef fish communities are species-poor compared to those of the Indo-West Pacific. An exception to that pattern is the blenny clade Chaenopsidae, one of only three rocky and coral reef fish families largely endemic to the Neotropics. Within the chaenopsids, the genus Acanthemblemaria is the most species-rich and is characterized by elaborate spinous processes on the skull. Here we construct a species tree using five nuclear markers and compare the results to those from Bayesian and parsimony phylogenetic analyses of 60 morphological characters. The sequence-based species tree conflicted with the morphological phylogenies for Acanthemblemaria, primarily due to the convergence of a suite of characters describing the distribution of spines on the head. However, we were able to resolve some of these conflicts by performing phylogenetic analyses on suites of characters not associated with head spines. By using the species tree as a guide, we used a quantitative method to identify suites of correlated morphological characters that, together, produce the distinctive skull phenotypes found in these fishes. A time calibrated phylogeny with nearly complete taxon sampling provided divergence time estimates that recovered a mid-Miocene origin for the genus, with a temporally and geographically complex pattern of speciation both before and after the closure of the Isthmus of Panama. Some sister taxa are broadly sympatric, but many occur in allopatry. The ability to infer the geography of speciation in Acanthemblemaria is complicated by extinctions, incomplete knowledge of their present geographic ranges and by wide-spread taxa that likely represent cryptic species complexes.

Coral reefs as drivers of cladogenesis: expanding coral reefs, cryptic extinction events, and the development of biodiversity hotspots

Diversification rates within four conspicuous coral reef fish families (Labridae, Chaetodontidae, Pomacentridae and Apogonidae) were estimated using Bayesian inference. Lineage through time plots revealed a possible late Eocene/early Oligocene cryptic extinction event coinciding with the collapse of the ancestral Tethyan/Arabian hotspot. Rates of diversification analysis revealed elevated cladogenesis in all families in the Oligocene/Miocene. Throughout the Miocene, lineages with a high percentage of coral reef-associated taxa display significantly higher net diversification rates than expected. The development of a complex mosaic of reef habitats in the Indo-Australian Archipelago (IAA) during the Oligocene/Miocene appears to have been a significant driver of cladogenesis. Patterns of diversification suggest that coral reefs acted as a refuge from high extinction, as reef taxa are able to sustain diversification at high extinction rates. The IAA appears to support both cladogenesis and survival in associated lineages, laying the foundation for the recent IAA marine biodiversity hotspot.

Fear of fishers: human predation explains behavioral changes in coral reef fishes.

Prey flight decisions in response to predation risk are increasingly being considered in conservation and management decisions in the terrestrial realm, but are rarely considered in marine systems. This field-based study investigated how the behavioral response of coral reef fish families varied along a gradient of subsistence fishing pressure in Papua New Guinea. Specifically, we examined how fishing pressure was related to pre-flight behavior and flight initiation distance (FID), and whether FID was influenced by body size (centimeters total length), group size (including both con- and hetero-specific individuals), or life-history phase. Fishing pressure was positively associated with higher FID, but only in families that were primarily targeted by spear guns. Among these families, there were variable responses in FID; some families showed increased FID monotonically with fishing pressure, while others showed increased FID only at the highest levels of fishing pressure. Body size was more significant in varying FID at higher levels of fishing pressure. Although family-level differences in pre-flight behavior were reported, such behavior showed low concordance with fishing pressure. FID shows promise as a tool by which compliance and effectiveness of management of reef fisheries can be assessed.

CORAL REEF FISHES IN THE COASTAL WATERS OF SOUTH-CENTRAL VIETNAM

Studies on coral reef fishes in the coastal waters of South Central Vietnam were conducted at 42 sites of coral reefs at the four major locations of Van Phong Bay, Nha Trang Bay, Ninh Hai - Ninh Thuan and Ca Na Bay from 2006 - 2007, and combined with available data of species composition from previous studies. A total of 578 species representing 180 genera and 40 families of coral reef fishes was recorded. The analysis and comparison indicate that diversity of coral reef fish fauna in the coastal waters of South Central Vietnam was higher than that in other locations in the coastal waters of Vietnam (the Tonkin Gulf, southeastern and southwestern waters of Vietnam), more or less similar to that in the Spratly Islands and many other locations around the world. In the coastal waters of South Central Vietnam, Nha Trang Bay supported a higher diversity and abundance of most of fish families than Van Phong Bay, Ninh Hai - Ninh Thuan and Ca Na Bay.

Using underwater cameras to assess the effects of snorkeler and SCUBA diver presence on coral reef fish abundance, family richness, and species composition

The results of underwater visual fish censuses (UVC) could be affected by fish changing their behavior in response to the snorkeler or diver conducting the survey. We used an underwater video camera to assess how fish abundance, family richness, and community composition were affected by the presence of snorkelers (n = 12) and self-contained underwater breathing apparatus (SCUBA) divers (n = 6) on a coral reef in Thailand. The total number of families, abundance of some fish families, and overall species composition showed significant differences before and during snorkeling disturbances. We did not detect significant and consistent changes to these parameters in the presence of a SCUBA diver; however, this could be a result of lower statistical power. We suggest that the use of a stationary video camera may help cross-check data that is collected through UVC to assess the true family composition and document the presence of rare and easily disturbed species.

Ontogeny of swimming speed in larvae of pelagic-spawning, tropical, marine fishes

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 349:255-267 (2007) - DOI: https://doi.org/10.3354/meps07107 Ontogeny of swimming speed in larvae of pelagic-spawning, tropical, marine fishes Jeffrey M. Leis1,3,*, Amanda C. Hay1, Matthew M. Lockett1, Jeng-Ping Chen2, Lee-Shing Fang2,4 1Ichthyology, Australian Museum, 6 College Street, Sydney, New South Wales 2010, Australia 2National Museum of Marine Biology and Aquarium, 2 Houwan Road, Checheng, Pingtung 944, Taiwan 3School of Biological Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia 4Present address: Department of Sport, Health and Leisure, Cheng Shiu University, 840 Chengcing Road, Niaosong hsiang, Kaohsiung County 83347, Taiwan *Email: jeff.leis@austmus.gov.au ABSTRACT: During the pelagic larval phase of teleost fishes, the larvae are subject to dispersal by currents. Dispersal trajectories can be substantially modified if the larvae have sufficient swimming abilities, so it is important to document how swimming ability develops during the pelagic larval phase. We used reared larvae (4 to 29 mm standard length) from commercial aquaculture farms in Taiwan to measure the development of swimming ability (critical speed, Ucrit) in larvae of 9 species (from 7 families) of Indo-Pacific coral reef and coastal fishes that hatch from pelagic eggs: Trachinotus blochii (Carangidae – jacks), Chanos chanos (Chanidae – milkfish), Platax teira (Ephippidae –batfishes), Leiognathus equulus (Leiognathidae – ponyfishes), Lutjanus malabaricus (Lutjanidae – snappers), Eleutheronema tetradactylum (Polynemidae – threadfins), and Epinephelus coioides, E. fuscoguttatus and E. malabaricus (Serranidae – groupers). Mean critical swimming speeds increased from <5 cm s–1 in the smallest larvae to a maximum of 47 cm s–1 in settlement stage larvae, with the increase in speed by the time of settlement ranging from 6- to 100-fold. Increase in swimming speed was more strongly correlated with size of larvae (R2 = 0.38 to 0.93, p < 0.005) than with age (correlation with age was absent in 3 species and explained 10 to 43% less variation than did size in the others). The relationship between speed and size was linear. In 6 species (T. blochii, C. chanos, L. malabaricus and the 3 Epinephelus species) speed increased at a rate of 2.1 to 2.6 cm s–1 for each 1 mm increase in size. Three species (P. teira, L. equulus and E. tetradactylum) had a significantly slower rate of increase of 1.3 to 1.7 cm s–1 for each 1 mm increase in size. On average, the best performers in each 1 mm size increment were 1.5 to 7.3 cm s–1 faster than mean performers, depending on species. Throughout development the vast majority of mean length-specific speeds were 10 to 20 body lengths (BL) s–1, and length-specific speed increased significantly with size in 6 species. Maximum length-specific speeds for each species reached 18 to 31 BL s–1. Although the ontogeny of swimming speed varies among species of tropical marine fishes, over similar size ranges, larvae that hatch from pelagic eggs have swimming abilities similar to those reported for larvae that hatch from demersal eggs. KEY WORDS: Marine fishes · Pelagic eggs · Pelagic larvae · Swimming speed · Ontogeny · Dispersal · Serranidae · Lutjanidae · Carangidae · Chanidae Full text in pdf format PreviousNextCite this article as: Leis JM, Hay AC, Lockett MM, Chen J, Fang L (2007) Ontogeny of swimming speed in larvae of pelagic-spawning, tropical, marine fishes. Mar Ecol Prog Ser 349:255-267. https://doi.org/10.3354/meps07107Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 349. Online publication date: November 08, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Distribution and factors influencing on structure of reef fish communities in Nha Trang Bay Marine Protected Area, South-Central Vietnam

Visual censuses of coral reef fishes in Nha Trang Bay Marine Protected Area (MPA) were conducted during September–October 2005. Nha Trang Bay MPA is relatively rich in reef fishes compared to other areas in Vietnam and the Pacific Ocean outside the ‘Coral Triangle,’ consistent with its biogeographic location in the western South China Sea. A total of 266 species of 40 families of coral reef fishes formed five distinct assemblages. Spatial variations in distribution and structure of the assemblages were associated with eight significant biological and physical variables which were cover of living hard corals, encrusting corals, branching corals, Acropora, Millepora, Montipora, depth and distance from the coast of the mainland. The six factors in front are likely related to provision of shelter and nutrition, while the distance factor is likely to represent a gradient in disturbance and impacts from various mainland sources including sedimentation and pollution discharge from nearby rivers. Local species richness ranged from 35 to 70 species 500 m−2 (mean: 51 ± 2 SE) for reef flat stations and from 23 to 68 species 500 m−2 (mean: 48 ± 4 SE) for reef slope stations. Total species richness at each site averaged 76 species (±4 SE), ranging from 56 to 110 species, dominated by wrasses, damselfishes, butterflyfishes, parrotfishes, surgeonfishes, groupers and goatfishes. Density of total fishes at each station ranged from 348 to 1,444 individuals 500 m−2 (mean: 722 ± 302 SE) for the reef flat stations and from 252 to 929 individuals 500 m−2 (mean: 536 ± 215.7 SE) for the reef slope stations. Overall mean density at each site averaged 628.9 (±238.4 SE) individuals 500 m−2. The highly protected sites supported higher mean density of fishes per site (ranged: 904.5–1,213 individuals 500 m−2 for Hon Mun and 1,167.5 individuals 500 m−2 for Hon Cau) compared to other sites (<800 individuals 500 m−2). Of the families included in the census, densities were dominated throughout the MPA by damselfishes and wrasses. Many target species, particularly groupers, snappers and emperors, were rare or absent and the low abundance of big fishes was consistent with over-harvesting. Similarly a low density of butterfly fishes and angelfishes is likely related to the supply for marine aquaria in Vietnam and overseas. This study provides an important baseline against which the success of present and future MPA management initiatives may be assessed.

Molecular phylogenetics of the butterflyfishes (Chaetodontidae): Taxonomy and biogeography of a global coral reef fish family

Marine butterflyfishes (10 genera, 114 species) are conspicuously beautiful and abundant animals found on coral reefs worldwide, and are well studied due to their ecological importance and commercial value. Several phylogenies based on morphological and molecular data exist, yet a well-supported molecular phylogeny at the species level for a wide range of taxa remains to be resolved. Here we present a molecular phylogeny of the butterflyfishes, including representatives of all genera (except Parachaetodon) and at least one representative of all commonly cited subgenera of Chaetodon (except Roa sensu Blum, 1988). Genetic data were collected for 71 ingroup and 13 outgroup taxa, using two nuclear and three mitochondrial genes that total 3332 nucleotides. Bayesian inference, parsimony, and maximum likelihood methods produced a well-supported phylogeny with strong support for a monophyletic Chaetodontidae. The Chaetodon subgenera Exornator and Chaetodon were found to be polyphyletic, and the genus Amphichaetodon was not the basal sister group to the rest of the family as had been previously proposed. Molecular phylogenetic analysis of data from 5 genes resolved some clades in agreement with previous phylogenetic studies, however the topology of relationships among major butterflyfish groups differed significantly from previous hypotheses. The analysis recovered a clade containing Amphichaetodon, Coradion, Chelmonops, Chelmon, Forcipiger, Hemitaurichthys, Johnrandallia, and Heniochus. Prognathodes was resolved as the sister to all Chaetodon, as in previous hypotheses, although the topology of subgeneric clades differed significantly from hypotheses based on morphology. We use the species-level phylogeny for the butterflyfishes to resolve long-standing questions regarding the use of subgenera in Chaetodon, to reconstruct molecular rates and estimated dates of diversification of major butterflyfish clades, and to examine global biogeographic patterns.

Life history patterns shape energy allocation among fishes on coral reefs

Although critically important, the link between animal life histories and ecosystem energetics is seldom explored. In the pursuit of ecological simplification, ecosystem properties are typically described by models based on static counts, where organisms are aggregated into trophic- or size-based groups. Consequently, output is often based on an assumption that larger group biomass equals greater energetic contribution. Here, we modelled the individual growth of over 58,000 fishes from 74 genera within a coral reef ecosystem to investigate the role and importance of taxon-specific life histories to the division, spatial distribution and relative contribution of biomass production within 14 coral reef fish families. Rank changes among families in standing biomass to biomass production indicated that small cryptic families (e.g. Gobiidae and Blenniidae) exhibit collective growth potentials equal to or exceeding those of many other common families composed of individuals with body-sizes 1-3 orders of magnitude larger. Remaining at high risk of predation throughout their lives as a consequence of their small size, these cryptic fishes also provide a constant food resource and supply of reproductive energy to coral reefs throughout the year. Enhanced further by the strength and diversity of their trophic relationships within food webs, the highly productive nature of these small cryptic fishes suggests they make a substantial contribution to the flow of energy in coral reef ecosystems via predatory pathways. It appears that life histories leave a strong imprint on ecosystem energy fluxes and illustrate the importance of incorporating taxon-specific features when assigning values to key ecosystem processes.

Ultraviolet photosensitivity and feeding in larval and juvenile coral reef fishes

The ability of young coral reef fishes to feed using solely ultraviolet-A (UV-A) radiation during ontogeny was examined using natural prey in experimental tanks. Larvae and juveniles of three coral reef fish species (Pomacentrus amboinensis, Premnas biaculeatus and Apogon compressus) are able to feed successfully using UV-A radiation alone during the later half of the pelagic larval phase. The minimum UV radiation intensities required for larval feeding occur in the field down to depths of 90–130 m in oceanic waters and 15–20 m in turbid inshore waters. There was no abrupt change in UV sensitivity after settlement, indicating that UV photosensitivity may continue to play a significant role in benthic juveniles on coral reefs. Tests of UV sensitivity in the field using light traps indicate that larval and juvenile stages of 16 coral reef fish families are able to detect and respond photopositively to UV wavelengths. These include representatives from families that are unlikely to possess UV sensitivity as adults due to the UV transmission characteristics of the ocular media. Functional UV sensitivity may be more widespread in young coral reef fishes than in the adults, and may play a significant role in detecting zooplanktonic prey.

The relationship between population genetic structure and pelagic larval duration in coral reef fishes on the Great Barrier Reef

Pelagic larval duration (PLD) is a commonly used proxy for dispersal potential in coral reef fishes. Here we examine the relationship between PLD, genetic structure and genetic variability in geographically widespread and ecological generalist species from one coral reef fish family (Pomacentridae) that differs in mean larval duration by more than a month. The genetic structure was estimated in eight species using a mitochondrial molecular marker (D-loop) and in a sub-set of five species using nuclear molecular markers (ISSRs). Estimates of genetic differentiation were similar among species with pelagic larvae, but differed between molecular markers. The mtDNA indicated no structure in all species except one, while the ISSR indicated some structure between the sampling locations in all species. We detected a relationship between PLD and genetic structure using both markers. These relationships, however, were caused by a single species, Acanthochromis polyacanthus, which differs from all the other species examined here in lacking a larval phase. With this species excluded, there was no relationship between PLD and genetic structure using either marker despite a range of PLDs of more than 20 days. Genetic diversities were generally high in all species and did not differ significantly among species and locations. Nucleotide diversity and total heterozygosity were negatively related to maximum PLD but again these relationships were caused by A. polyacanthus and disappeared when this species was excluded. These genetic patterns are consistent with moderate gene flow among well-connected locations and indicate that at this phylogenetic level (i.e., within family) the duration of the pelagic larval phase is unrelated to the patterns of genetic differentiation.

Wave energy and swimming performance shape coral reef fish assemblages

Physical factors often have an overriding influence on the distribution patterns of organisms, and can ultimately shape the long-term structure of communities. Although distribution patterns in sessile marine organisms have frequently been attributed to functional characteristics interacting with wave-induced water motion, similar evidence for mobile organisms is lacking. Links between fin morphology and swimming performance were examined in three diverse coral reef fish families from two major evolutionary lineages. Among-habitat variation in morphology and performance was directly compared with quantitative values of wave-induced water motion from seven coral reef habitats of different depth and wave exposure on the Great Barrier Reef. Fin morphology was strongly correlated with both field and experimental swimming speeds in all three families. The range of observed swimming speeds coincided closely with the magnitude of water velocities commonly found on coral reefs. Distribution patterns in all three families displayed highly congruent relationships between fin morphology and wave-induced water motion. Our findings indicate a general functional relationship between fin morphology and swimming performance in labriform-swimming fishes, and provide quantitative evidence that wave energy may directly influence the assemblage structure of coral reef fishes through interactions with morphology and swimming performance.

Wave-induced water motion and the functional implications for coral reef fish assemblages

Using a functional approach, we quantified water motion and the distribution of fish swimming modes across five habitat zones and four exposure regimes commonly found on coral reefs. There were major spatial variations in net flow velocity (7.4–43.2 cm s21) and rates of flow direction change (0.06–0.66 Hz) among habitats of different depth. Water motion within the shallow crest and flat habitats appeared to be largely wave driven, with rates of flow direction change (0.63–0.66 Hz) corresponding with approximately double the wave periodicity (0.31–0.36 Hz) and relatively little contribution (14–16%) from drift flow velocities. A similar variation in water motion was found among reefs of different exposure, with the highest and lowest velocities recorded in the exposed and sheltered locations, respectively. Exposed and oblique reef crests displayed greater temporal variation in wave height and water motion (24.4–59.5 cm s21 net velocities) when compared with the relatively static conditions in sheltered (6.2–12.6 cm s21) and lagoonal sites (17.1–25.3 cm s21). We examined the distribution and functional structure of seven coral reef fish families (156 species) across the full range of water motion variation on these reefs. Pectoral-swimming fishes were the most abundant group, predominating in areas with high levels of water motion; pectoral-caudal– and caudal-swimming fishes displayed the opposite trend. We suggest that these differences are the result of an interaction between water motion and the biomechanical and energetic attributes associated with each swimming mode.

Attraction of settlement-stage coral reef fishes to reef noise

We compared catches of settlement-stage reef fishes in light traps attached to under- water speakers playing reef sounds with those of silent traps during a summer recruitment season at Lizard Island, Great Barrier Reef, Australia. Of the total 40191 reef fishes we collected, significantly more (67%; Wilcoxon and Binomial tests: p< 0.001) appeared in the traps with broadcast reef noise. Traps deployed with speakers consistently caught a greater diversity of species (Wilcoxon test: p< 0.001, total 81 vs 68) than did silent traps. This study provides a clear demonstration that the settlement-stages of a broad range of families of coral reef fishes are attracted to reef sounds.

Diversity of pectoral fin structure and function in fishes with labriform propulsion

Aquatic propulsion generated by the pectoral fins occurs in many groups of perciform fishes, including numerous coral reef families. This study presents a detailed survey of pectoral fin musculoskeletal structure in fishes that use labriform propulsion as the primary mode of swimming over a wide range of speeds. Pectoral fin morphological diversity was surveyed in 12 species that are primarily pectoral swimmers, including members of all labroid families (Labridae, Scaridae, Cichlidae, Pomacentridae, and Embiotocidae) and five additional coral reef fish families. The anatomy of the pectoral fin musculature is described, including muscle origins, insertions, tendons, and muscle masses. Skeletal structures are also described, including fin shape, fin ray morphology, and the structure of the radials and pectoral girdle. Three novel muscle subdivisions, including subdivisions of the abductor superficialis, abductor profundus, and adductor medialis were discovered and are described here. Specific functional roles in fin control are proposed for each of the novel muscle subdivisions. Pectoral muscle masses show broad variation among species, particularly in the adductor profundus, abductor profundus, arrector dorsalis, and abductor superficialis. A previously undescribed system of intraradial ligaments was also discovered in all taxa studied. The morphology of these ligaments and functional ramifications of variation in this connective tissue system are described. Musculoskeletal patterns are interpreted in light of recent analyses of fin behavior and motor control during labriform swimming. Labriform propulsion has apparently evolved independently multiple times in coral reef fishes, providing an excellent system in which to study the evolution of pectoral fin propulsion.

Alimentary tract morphology and diet in three coral reef fish families

Alimentary tract morphology and its relationship with diet was examined in three coral reef fish families: Labridae, Chaetodontidae and Pomacentridae. Convergent patterns of dietary‐related morphological variation were evident across the three families, with corallivores possessing long and narrow intestines, carnivores relatively short and wide intestines and herbivores relatively long and wide intestines. Between‐family differences were also evident: chaetodontids typically possessed long and narrow intestines, pomacentrids long and wide intestines and labrids generally possessed short and wide intestines. Overall, intestinal length variation was most strongly attributable to diet, whilst intestinal diameter varied most widely among families. Relative intestinal length appears as a useful predictor of dietary variation, particularly within families. Relative intestinal diameter appears as a less reliable measure, but rather, a useful adjunct to intestinal length comparisons.

The importance of sound for navigation at settlement in coral reef fishes, with reference to the development of the auditory response

The behavioral mechanisms that larval coral reef fishes employ to locate suitable settlement habitats on their return from the plankton are poorly understood. The response of settlement-stage reef fishes to reef noise was studied at Lizard Island, Great Barrier Reef, Australia. Catches of fishes in light traps attached to underwater speakers playing reef sounds were twice those of silent traps. To demonstrate that this attraction is important during settlement, sound was used to favorably attract settlers to noisy (over silent) artificial reefs. Many coral reef fish families lay eggs demersally on the reef. By monitoring the heart rates of clownfish embryos in response to artificial noise signals, a broadening of the spectral range of response and a lowering of the threshold of response (an increase in sensitivity) was identified during their development. The thresholds suggest that these embryonic fish will have experienced coral reef noises prior to leaving the reef. These studies clearly demonstrate the use of sound as a navigation cue for settlement-stage coral reef fishes, and suggest the potential for imprinting. Our findings not only have major implications for how we model recruitment, but also offer some potential management tools for reef systems. [Work supported by Natural Environment Research Council (UK), British Association, Australian Institute of Marine Science, National Organization for Hearing Research (USA), Institute of Museum and Library Services (USA), Department of Education (USA).]