Morphohistology of the Digestive Tract of the Damsel Fish Stegastes fuscus (Osteichthyes: Pomacentridae

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Bhaskara Canan

2012-01-01

Full Text Available This study investigated the morphohistology of the digestive tract and the mean intestinal coefficient of the damsel fish Stegastes fuscus captured from the tidal pools of Northeastern Brazil. The wall of the digestive tract of S. fuscus is composed of the tunica mucosa, tunica muscularis, and tunica serosa. The esophagus is short with sphincter and thick distensible wall with longitudinally folded mucosa. Mucous glands are predominant, and the muscular layer of the esophagus presented striated fibers all along its extension. The transition region close to the stomach shows plain and striated muscular fibers. Between the stomach and intestine, there are three pyloric caeca. The intestine is long and thin with four folds around the stomach. The anterior intestine presents folds similar to those of pyloric caeca. The estimated mean intestinal coefficient and characteristics of the digestive system of S. fuscus present morphological adequacy for both herbivorous and omnivorous feeding habits.

Whole gut microbiome composition of damselfish and cardinalfish before and after reef settlement

OpenAIRE

Parris, Darren J.; Brooker, Rohan M.; Morgan, Michael A.; Dixson, Danielle L.; Stewart, Frank J.

2016-01-01

The Pomacentridae (damselfish) and Apogonidae (cardinalfish) are among the most common fish families on coral reefs and in the aquarium trade. Members of both families undergo a pelagic larvae phase prior to settlement on the reef, where adults play key roles in benthic habitat structuring and trophic interactions. Fish-associated microbial communities (microbiomes) significantly influence fish health and ecology, yet little is known of how microbiomes change with life stage. We quantified th...

Bipartite life cycle of coral reef fishes promotes increasing shape disparity of the head skeleton during ontogeny: an example from damselfishes (Pomacentridae

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Vandewalle Pierre

2011-03-01

Full Text Available Abstract Background Quantitative studies of the variation of disparity during ontogeny exhibited by the radiation of coral reef fishes are lacking. Such studies dealing with the variation of disparity, i.e. the diversity of organic form, over ontogeny could be a first step in detecting evolutionary mechanisms in these fishes. The damselfishes (Pomacentridae have a bipartite life-cycle, as do the majority of demersal coral reef fishes. During their pelagic dispersion phase, all larvae feed on planktonic prey. On the other hand, juveniles and adults associated with the coral reef environment show a higher diversity of diets. Using geometric morphometrics, we study the ontogenetic dynamic of shape disparity of different head skeletal units (neurocranium, suspensorium and opercle, mandible and premaxilla in this fish family. We expected that larvae of different species might be relatively similar in shapes. Alternatively, specialization may become notable even in the juvenile and adult phase. Results The disparity levels increase significantly throughout ontogeny for each skeletal unit. At settlement, all larval shapes are already species-specific. Damselfishes show high levels of ontogenetic allometry during their post-settlement growth. The divergence of allometric patterns largely explains the changes in patterns and levels of shape disparity over ontogeny. The rate of shape change and the length of ontogenetic trajectories seem to be less variable among species. We also show that the high levels of shape disparity at the adult stage are correlated to a higher level of ecological and functional diversity in this stage. Conclusion Diversification throughout ontogeny of damselfishes results from the interaction among several developmental novelties enhancing disparity. The bipartite life-cycle of damselfishes exemplifies a case where the variation of environmental factors, i.e. the transition from the more homogeneous oceanic environment to the

Bipartite life cycle of coral reef fishes promotes increasing shape disparity of the head skeleton during ontogeny: an example from damselfishes (Pomacentridae)

Science.gov (United States)

2011-01-01

Background Quantitative studies of the variation of disparity during ontogeny exhibited by the radiation of coral reef fishes are lacking. Such studies dealing with the variation of disparity, i.e. the diversity of organic form, over ontogeny could be a first step in detecting evolutionary mechanisms in these fishes. The damselfishes (Pomacentridae) have a bipartite life-cycle, as do the majority of demersal coral reef fishes. During their pelagic dispersion phase, all larvae feed on planktonic prey. On the other hand, juveniles and adults associated with the coral reef environment show a higher diversity of diets. Using geometric morphometrics, we study the ontogenetic dynamic of shape disparity of different head skeletal units (neurocranium, suspensorium and opercle, mandible and premaxilla) in this fish family. We expected that larvae of different species might be relatively similar in shapes. Alternatively, specialization may become notable even in the juvenile and adult phase. Results The disparity levels increase significantly throughout ontogeny for each skeletal unit. At settlement, all larval shapes are already species-specific. Damselfishes show high levels of ontogenetic allometry during their post-settlement growth. The divergence of allometric patterns largely explains the changes in patterns and levels of shape disparity over ontogeny. The rate of shape change and the length of ontogenetic trajectories seem to be less variable among species. We also show that the high levels of shape disparity at the adult stage are correlated to a higher level of ecological and functional diversity in this stage. Conclusion Diversification throughout ontogeny of damselfishes results from the interaction among several developmental novelties enhancing disparity. The bipartite life-cycle of damselfishes exemplifies a case where the variation of environmental factors, i.e. the transition from the more homogeneous oceanic environment to the coral reef offering a wide

Whole gut microbiome composition of damselfish and cardinalfish before and after reef settlement.

Science.gov (United States)

Parris, Darren J; Brooker, Rohan M; Morgan, Michael A; Dixson, Danielle L; Stewart, Frank J

2016-01-01

The Pomacentridae (damselfish) and Apogonidae (cardinalfish) are among the most common fish families on coral reefs and in the aquarium trade. Members of both families undergo a pelagic larvae phase prior to settlement on the reef, where adults play key roles in benthic habitat structuring and trophic interactions. Fish-associated microbial communities (microbiomes) significantly influence fish health and ecology, yet little is known of how microbiomes change with life stage. We quantified the taxonomic (16S rRNA gene) composition of whole gut microbiomes from ten species of damselfish and two species of cardinalfish from Lizard Island, Australia, focusing specifically on comparisons between pelagic larvae prior to settlement on the reef versus post-settlement juvenile and adult individuals. On average, microbiome phylogenetic diversity increased from pre- to post-settlement, and was unrelated to the microbial composition in the surrounding water column. However, this trend varied among species, suggesting stochasticity in fish microbiome assembly. Pre-settlement fish were enriched with bacteria of the Endozoicomonaceae, Shewanellaceae, and Fusobacteriaceae, whereas settled fish harbored higher abundances of Vibrionaceae and Pasteurellaceae. Several individual operational taxonomic units, including ones related to Vibrio harveyi, Shewanella sp., and uncultured Endozoicomonas bacteria, were shared between both pre and post-settlement stages and may be of central importance in the intestinal niche across development. Richness of the core microbiome shared among pre-settlement fish was comparable to that of settled individuals, suggesting that changes in diversity with adulthood are due to the acquisition or loss of host-specific microbes. These results identify a key transition in microbiome structure across host life stage, suggesting changes in the functional contribution of microbiomes over development in two ecologically dominant reef fish families.

Whole gut microbiome composition of damselfish and cardinalfish before and after reef settlement

Directory of Open Access Journals (Sweden)

Darren J. Parris

2016-08-01

Full Text Available The Pomacentridae (damselfish and Apogonidae (cardinalfish are among the most common fish families on coral reefs and in the aquarium trade. Members of both families undergo a pelagic larvae phase prior to settlement on the reef, where adults play key roles in benthic habitat structuring and trophic interactions. Fish-associated microbial communities (microbiomes significantly influence fish health and ecology, yet little is known of how microbiomes change with life stage. We quantified the taxonomic (16S rRNA gene composition of whole gut microbiomes from ten species of damselfish and two species of cardinalfish from Lizard Island, Australia, focusing specifically on comparisons between pelagic larvae prior to settlement on the reef versus post-settlement juvenile and adult individuals. On average, microbiome phylogenetic diversity increased from pre- to post-settlement, and was unrelated to the microbial composition in the surrounding water column. However, this trend varied among species, suggesting stochasticity in fish microbiome assembly. Pre-settlement fish were enriched with bacteria of the Endozoicomonaceae, Shewanellaceae, and Fusobacteriaceae, whereas settled fish harbored higher abundances of Vibrionaceae and Pasteurellaceae. Several individual operational taxonomic units, including ones related to Vibrio harveyi, Shewanella sp., and uncultured Endozoicomonas bacteria, were shared between both pre and post-settlement stages and may be of central importance in the intestinal niche across development. Richness of the core microbiome shared among pre-settlement fish was comparable to that of settled individuals, suggesting that changes in diversity with adulthood are due to the acquisition or loss of host-specific microbes. These results identify a key transition in microbiome structure across host life stage, suggesting changes in the functional contribution of microbiomes over development in two ecologically dominant reef fish

An Indo-Pacific damselfish (Neopomacentrus cyanomos) in the Gulf of Mexico: origin and mode of introduction.

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Robertson, D Ross; Dominguez-Dominguez, Omar; Victor, Benjamin; Simoes, Nuno

2018-01-01

The Indo-West Pacific (IWP) coral-reef damselfish Neopomacentrus cyanomos is well established across the south-west Gulf of Mexico (SwGoMx). Comparisons of mtDNA sequences of the SwGoMx population with those from conspecifics from 16 sites scattered across its native geographic range show that the SwGoMx population is derived from two of four native lineages: one from the north-west Pacific Ocean, the other from the northern Indian Ocean. Three hypotheses address how this species was introduced to the SwGoMX: (1) aquarium release; (2) borne by cargo-ship; and (3) carried by offshore petroleum platform (petro-platform). The first is unlikely because this species rarely features in the aquarium trade, and " N. cyanomos " traded to the USA from the sole IWP source we are aware of are a misidentified congener, N. taeniurus . The second hypothesis is unlikely because shipping has not been associated with the introduction of alien damselfishes, there is little international shipping between the IWP and the SwGoMx, and voyages between those areas would be lengthy and along environmentally unfavorable routes. Various lines of evidence support the third hypothesis: (i) bio-fouled petro-platforms represent artificial reefs that can sustain large and diverse populations of tropical reef-fishes, including N. cyanomos in the SwGoMx; (ii) relocation of such platforms has been implicated in trans-oceanic introductions leading to establishment of non-native populations of such fishes; and (iii) genetic characteristics of the SwGoMx population indicate that it was established by a large and diverse group of founders drawn from the IWP regions where many petro-platforms currently in the SwGoMx and other Atlantic offshore oilfields originated.

An Indo-Pacific damselfish (Neopomacentrus cyanomos in the Gulf of Mexico: origin and mode of introduction

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D. Ross Robertson

2018-02-01

Full Text Available The Indo-West Pacific (IWP coral-reef damselfish Neopomacentrus cyanomos is well established across the south-west Gulf of Mexico (SwGoMx. Comparisons of mtDNA sequences of the SwGoMx population with those from conspecifics from 16 sites scattered across its native geographic range show that the SwGoMx population is derived from two of four native lineages: one from the north-west Pacific Ocean, the other from the northern Indian Ocean. Three hypotheses address how this species was introduced to the SwGoMX: (1 aquarium release; (2 borne by cargo-ship; and (3 carried by offshore petroleum platform (petro-platform. The first is unlikely because this species rarely features in the aquarium trade, and “N. cyanomos” traded to the USA from the sole IWP source we are aware of are a misidentified congener, N. taeniurus. The second hypothesis is unlikely because shipping has not been associated with the introduction of alien damselfishes, there is little international shipping between the IWP and the SwGoMx, and voyages between those areas would be lengthy and along environmentally unfavorable routes. Various lines of evidence support the third hypothesis: (i bio-fouled petro-platforms represent artificial reefs that can sustain large and diverse populations of tropical reef-fishes, including N. cyanomos in the SwGoMx; (ii relocation of such platforms has been implicated in trans-oceanic introductions leading to establishment of non-native populations of such fishes; and (iii genetic characteristics of the SwGoMx population indicate that it was established by a large and diverse group of founders drawn from the IWP regions where many petro-platforms currently in the SwGoMx and other Atlantic offshore oilfields originated.

An Indo-Pacific damselfish (Neopomacentrus cyanomos) in the Gulf of Mexico: origin and mode of introduction

Science.gov (United States)

Dominguez-Dominguez, Omar; Victor, Benjamin; Simoes, Nuno

2018-01-01

The Indo-West Pacific (IWP) coral-reef damselfish Neopomacentrus cyanomos is well established across the south-west Gulf of Mexico (SwGoMx). Comparisons of mtDNA sequences of the SwGoMx population with those from conspecifics from 16 sites scattered across its native geographic range show that the SwGoMx population is derived from two of four native lineages: one from the north-west Pacific Ocean, the other from the northern Indian Ocean. Three hypotheses address how this species was introduced to the SwGoMX: (1) aquarium release; (2) borne by cargo-ship; and (3) carried by offshore petroleum platform (petro-platform). The first is unlikely because this species rarely features in the aquarium trade, and “N. cyanomos” traded to the USA from the sole IWP source we are aware of are a misidentified congener, N. taeniurus. The second hypothesis is unlikely because shipping has not been associated with the introduction of alien damselfishes, there is little international shipping between the IWP and the SwGoMx, and voyages between those areas would be lengthy and along environmentally unfavorable routes. Various lines of evidence support the third hypothesis: (i) bio-fouled petro-platforms represent artificial reefs that can sustain large and diverse populations of tropical reef-fishes, including N. cyanomos in the SwGoMx; (ii) relocation of such platforms has been implicated in trans-oceanic introductions leading to establishment of non-native populations of such fishes; and (iii) genetic characteristics of the SwGoMx population indicate that it was established by a large and diverse group of founders drawn from the IWP regions where many petro-platforms currently in the SwGoMx and other Atlantic offshore oilfields originated. PMID:29441235

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

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Bonin, M. C.

2012-03-01

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

Social structure affects mating competition in a damselfish

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Wacker, Sebastian; Ness, Miriam Horstad; Östlund-Nilsson, Sara; Amundsen, Trond

2017-12-01

The strength of mating competition and sexual selection varies over space and time in many animals. Such variation is typically driven by ecological and demographic factors, including adult sex ratio and consequent availability of mates. The spatial scale at which demographic factors affect mating competition and sexual selection may vary but is not often investigated. Here, we analyse variation in size and sex ratio of social groups, and how group structure affects mating competition, in the site-attached damselfish Chrysiptera cyanea. Site-attached reef fishes are known to show extensive intraspecific variation in social structure. Previous work has focused on species for which the size and dynamics of social groups are constrained by habitat, whereas species with group structure unconstrained by habitat have received little attention. Chrysiptera cyanea is such a species, with individuals occurring in spatial clusters that varied widely in size and sex ratio. Typically, only one male defended a nest in multi-male groups. Nest-holding males were frequently visited by mate-searching females, with more visits in groups with more females, suggesting that courtship and mating mostly occur within groups and that male mating success depends on the number of females in the group. Male-male aggression was frequent in multi-male groups but absent in single-male groups. These findings demonstrate that groups are distinct social units. In consequence, the dynamics of mating and reproduction are mainly a result of group structure, largely unaffected short term by overall population demography which would be important in open social systems. Future studies of the C. cyanea model system should analyse longer-term dynamics, including how groups are formed, how they vary in relation to density and time of season and how social structure affects sexual selection.

Dopamine D1 receptor activation leads to object recognition memory in a coral reef fish.

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Hamilton, Trevor J; Tresguerres, Martin; Kline, David I

2017-07-01

Object recognition memory is the ability to identify previously seen objects and is an adaptive mechanism that increases survival for many species throughout the animal kingdom. Previously believed to be possessed by only the highest order mammals, it is now becoming clear that fish are also capable of this type of memory formation. Similar to the mammalian hippocampus, the dorsolateral pallium regulates distinct memory processes and is modulated by neurotransmitters such as dopamine. Caribbean bicolour damselfish ( Stegastes partitus ) live in complex environments dominated by coral reef structures and thus likely possess many types of complex memory abilities including object recognition. This study used a novel object recognition test in which fish were first presented two identical objects, then after a retention interval of 10 min with no objects, the fish were presented with a novel object and one of the objects they had previously encountered in the first trial. We demonstrate that the dopamine D 1 -receptor agonist (SKF 38393) induces the formation of object recognition memories in these fish. Thus, our results suggest that dopamine-receptor mediated enhancement of spatial memory formation in fish represents an evolutionarily conserved mechanism in vertebrates. © 2017 The Author(s).

Loss of live coral compromises predator-avoidance behaviour in coral reef damselfish.

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Boström-Einarsson, Lisa; Bonin, Mary C; Munday, Philip L; Jones, Geoffrey P

2018-05-17

Tropical reefs have experienced an unprecedented loss of live coral in the past few decades and the biodiversity of coral-dependent species is under threat. Many reef fish species decline in abundance as coral cover is lost, yet the mechanisms responsible for these losses are largely unknown. A commonly hypothesised cause of fish decline is the loss of shelter space between branches as dead corals become overgrown by algae. Here we tested this hypothesis by quantifying changes in predator-avoidance behaviour of a common damselfish, Pomacentrus moluccensis, before and after the death of their coral colony. Groups of P. moluccensis were placed on either healthy or degraded coral colonies, startled using a visual stimulus and their sheltering responses compared over a 7-week period. P. moluccensis stopped sheltering amongst the coral branches immediately following the death of the coral, despite the presence of ample shelter space. Instead, most individuals swam away from the dead coral, potentially increasing their exposure to predators. It appears that the presence of live coral rather than shelter per se is the necessary cue that elicits the appropriate behavioural response to potential predators. The disruption of this link poses an immediate threat to coral-associated fishes on degrading reefs.

Effect of Three-spot Seahorse Petroleum Ether Extract on Lipopolysaccharide Induced Macrophage RAW264.7 Inflammatory Cytokine Nitric Oxide and Composition Analysis.

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Chen, LiPing; Shen, XuanRi; Chen, GuoHua; Cao, XianYing; Yang, Jian

2015-01-01

Three-Spot seahorse is a traditional medicine in Asian countries. However, the alcohol extract is largely unknown for its anti-inflammatory activity. This study aimed at elucidating fraction of potent anti-inflammatory activity of seahorse. A systematic solvent extraction method of liquid-liquid fractionation of ethanol crude extract gave four fractions petroleum ether (PE), and ethyl acetate (EtOAc), water saturated butanol (n-BuOH), water (H2O). In this study, PE extract was selected for further study after preliminary screening test, and was connected to silica column chromatography and eluted with different polarity of mobile phases, and obtained four active fractions (Fr I, Fr II, Fr III, Fr IV). Effect of separated fractions on inflammation was investigated in lipopolysaccharide (LPS) stimulated murine RAW264.7 cells in vitro. The result shows that seahorse extract was capable of inhibiting the production of nitric oxide (NO) significantly in a dose dependent manner and exhibited no notable cytotoxicity on cell viability. IC50 of fraction IV was 36.31 μg/mL, indicating that separated fraction possessed potent NO inhibitory activity against LPS-induced inflammatory response, thus, demonstrated its in vitro anti-inflammatory potentiality, it may be at least partially explained by the presence of anti-inflammation active substances, phenolic compounds, phospholipids and polyunsaturated fatty acids, especially phospholipids and polyunsaturated fatty acids. It could be suggested that seahorse lipid-soluble components could be used in functional food and anti-inflammatory drug preparations.

Regional-scale variation in the distribution and abundance of farming damselfishes on Australia's Great Barrier Reef

KAUST Repository

Emslie, Michael J.; Logan, Murray; Ceccarelli, Daniela M.; Cheal, Alistair J.; Hoey, Andrew; Miller, Ian R.; Sweatman, Hugh P A

2012-01-01

Territorial damselfishes that manipulate ("farm") the algae in their territories can have a marked effect on benthic community structure and may influence coral recovery following disturbances. Despite the numerical dominance of farming species on many reefs, the importance of their grazing activities is often overlooked, with most studies only examining their roles over restricted spatial and temporal scales. We used the results of field surveys covering 9.5° of latitude of the Great Barrier Reef to describe the distribution, abundance and temporal dynamics of farmer communities. Redundancy analysis revealed unique subregional assemblages of farming species that were shaped by the combined effects of shelf position and, to a lesser extent, by latitude. These spatial patterns were largely stable through time, except when major disturbances altered the benthic community. Such disturbances affected the functional guilds of farmers in different ways. Since different guilds of farmers modify benthic community structure and affect survival of juvenile corals in different ways, these results have important implications for coral recovery following disturbances. © 2012 Springer-Verlag.

Regional-scale variation in the distribution and abundance of farming damselfishes on Australia's Great Barrier Reef

KAUST Repository

Emslie, Michael J.

2012-03-15

Territorial damselfishes that manipulate ("farm") the algae in their territories can have a marked effect on benthic community structure and may influence coral recovery following disturbances. Despite the numerical dominance of farming species on many reefs, the importance of their grazing activities is often overlooked, with most studies only examining their roles over restricted spatial and temporal scales. We used the results of field surveys covering 9.5° of latitude of the Great Barrier Reef to describe the distribution, abundance and temporal dynamics of farmer communities. Redundancy analysis revealed unique subregional assemblages of farming species that were shaped by the combined effects of shelf position and, to a lesser extent, by latitude. These spatial patterns were largely stable through time, except when major disturbances altered the benthic community. Such disturbances affected the functional guilds of farmers in different ways. Since different guilds of farmers modify benthic community structure and affect survival of juvenile corals in different ways, these results have important implications for coral recovery following disturbances. © 2012 Springer-Verlag.

Productivity and sea surface temperature are correlated with the pelagic larval duration of damselfishes in the Red Sea.

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Robitzch, Vanessa S N; Lozano-Cortés, Diego; Kandler, Nora M; Salas, Eva; Berumen, Michael L

2016-04-30

We examined the variation of pelagic larval durations (PLDs) among three damselfishes, Dascyllus aruanus, D. marginatus, and D. trimaculatus, which live under the influence of an environmental gradient in the Red Sea. PLDs were significantly correlated with latitude, sea surface temperature (SST), and primary production (CHLA; chlorophyll a concentrations). We find a consistent decrease in PLDs with increasing SST and primary production (CHLA) towards the southern Red Sea among all species. This trend is likely related to higher food availability and increased metabolic rates in that region. We suggest that food availability is a potentially stronger driver of variation in PLD than temperature, especially in highly oligotrophic regions. Additionally, variations in PLDs were particularly high among specimens of D. marginatus, suggesting a stronger response to local environmental differences for endemic species. We also report the first average PLD for this species over a broad geographic range (19.82 ± 2.92 days). Copyright © 2015 Elsevier Ltd. All rights reserved.

Productivity and sea surface temperature are correlated with the pelagic larval duration of damselfishes in the Red Sea

KAUST Repository

Robitzch, Vanessa S.N.

2015-12-01

We examined the variation of pelagic larval durations (PLDs) among three damselfishes, Dascyllus aruanus, D. marginatus, and D. trimaculatus, which live under the influence of an environmental gradient in the Red Sea. PLDs were significantly correlated with latitude, sea surface temperature (SST), and primary production (CHLA; chlorophyll a concentrations). We find a consistent decrease in PLDs with increasing SST and primary production (CHLA) towards the southern Red Sea among all species. This trend is likely related to higher food availability and increased metabolic rates in that region. We suggest that food availability is a potentially stronger driver of variation in PLD than temperature, especially in highly oligotrophic regions. Additionally, variations in PLDs were particularly high among specimens of D. marginatus, suggesting a stronger response to local environmental differences for endemic species. We also report the first average PLD for this species over a broad geographic range (19.82 ± 2.92 days).

Productivity and sea surface temperature are correlated with the pelagic larval duration of damselfishes in the Red Sea

KAUST Repository

Robitzch, Vanessa S.N.; Lozano-Corté s, Diego; Kandler, Nora; Salas, Eva; Berumen, Michael L.

2015-01-01

We examined the variation of pelagic larval durations (PLDs) among three damselfishes, Dascyllus aruanus, D. marginatus, and D. trimaculatus, which live under the influence of an environmental gradient in the Red Sea. PLDs were significantly correlated with latitude, sea surface temperature (SST), and primary production (CHLA; chlorophyll a concentrations). We find a consistent decrease in PLDs with increasing SST and primary production (CHLA) towards the southern Red Sea among all species. This trend is likely related to higher food availability and increased metabolic rates in that region. We suggest that food availability is a potentially stronger driver of variation in PLD than temperature, especially in highly oligotrophic regions. Additionally, variations in PLDs were particularly high among specimens of D. marginatus, suggesting a stronger response to local environmental differences for endemic species. We also report the first average PLD for this species over a broad geographic range (19.82 ± 2.92 days).

Predator effects on reef fish settlement depend on predator origin and recruit density.

Science.gov (United States)

Benkwitt, Cassandra E

2017-04-01

During major life-history transitions, animals often experience high mortality rates due to predation, making predator avoidance particularly advantageous during these times. There is mixed evidence from a limited number of studies, however, regarding how predator presence influences settlement of coral-reef fishes and it is unknown how other potentially mediating factors, including predator origin (native vs. nonnative) or interactions among conspecific recruits, mediate the non-consumptive effects of predators on reef fish settlement. During a field experiment in the Caribbean, approximately 52% fewer mahogany snapper (Lutjanus mahogoni) recruited to reefs with a native predator (graysby grouper, Cephalopholis cruentata) than to predator-free control reefs and reefs with an invasive predator (red lionfish, Pterois volitans) regardless of predator diet. These results suggest that snapper recruits do not recognize nonnative lionfish as a threat. However, these effects depended on the density of conspecific recruits, with evidence that competition may limit the response of snapper to even native predators at the highest recruit densities. In contrast, there was no effect of predator presence or conspecific density on the recruitment of bicolor damselfish (Stegastes partitus). These context-dependent responses of coral-reef fishes to predators during settlement may influence individual survival and shape subsequent population and community dynamics. © 2017 by the Ecological Society of America.

Temperature influences selective mortality during the early life stages of a coral reef fish.

Directory of Open Access Journals (Sweden)

Tauna L Rankin

2011-05-01

Full Text Available For organisms with complex life cycles, processes occurring at the interface between life stages can disproportionately impact survival and population dynamics. Temperature is an important factor influencing growth in poikilotherms, and growth-related processes are frequently correlated with survival. We examined the influence of water temperature on growth-related early life history traits (ELHTs and differential mortality during the transition from larval to early juvenile stage in sixteen monthly cohorts of bicolor damselfish Stegastes partitus, sampled on reefs of the upper Florida Keys, USA over 6 years. Otolith analysis of settlers and juveniles coupled with environmental data revealed that mean near-reef water temperature explained a significant proportion of variation in pelagic larval duration (PLD, early larval growth, size-at-settlement, and growth during early juvenile life. Among all cohorts, surviving juveniles were consistently larger at settlement, but grew more slowly during the first 6 d post-settlement. For the other ELHTs, selective mortality varied seasonally: during winter and spring months, survivors exhibited faster larval growth and shorter PLDs, whereas during warmer summer months, selection on PLD reversed and selection on larval growth became non-linear. Our results demonstrate that temperature not only shapes growth-related traits, but can also influence the direction and intensity of selective mortality.

Protogyny in a tropical damselfish: females queue for future benefit

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Mark I. McCormick

2016-06-01

Full Text Available Membership of the group is a balance between the benefits associated with group living and the cost of socially constrained growth and breeding opportunities, but the costs and benefits are seldom examined. The goal of the present study was to explore the trade-offs associated with group living for a sex-changing, potentially protogynous coral reef fish, the Ambon damselfish, Pomacentrus amboinensis. Extensive sampling showed that the species exhibits resource defence polygyny, where dominant males guard a nest site that is visited by females. P. amboinensis have a longevity of about 6.5 years on the northern Great Barrier Reef. While the species can change sex consistent with being a protogynous hermaphrodite, it is unclear the extent to which the species uses this capability. Social groups are comprised of one reproductive male, 1–7 females and a number of juveniles. Females live in a linear dominance hierarchy, with the male being more aggressive to the beta-female than the alpha-female, who exhibits lower levels of ovarian cortisol. Surveys and a tagging study indicated that groups were stable for at least three months. A passive integrated transponder tag study showed that males spawn with females from their own group, but also females from neighbouring groups. In situ behavioural observations found that alpha-females have priority of access to the nest site that the male guarded, and access to higher quality foraging areas. Male removal studies suggest that the alpha-females can change sex to take over from the male when the position becomes available. Examination of otolith microstructure showed that those individuals which change sex to males have different embryonic characteristics at hatching, suggesting that success may involve a component that is parentally endowed. The relative importance of parental effects and social organisation in affecting the importance of female queuing is yet to be studied, but will likely depend on the

Protogyny in a tropical damselfish: females queue for future benefit.

Science.gov (United States)

McCormick, Mark I

2016-01-01

Membership of the group is a balance between the benefits associated with group living and the cost of socially constrained growth and breeding opportunities, but the costs and benefits are seldom examined. The goal of the present study was to explore the trade-offs associated with group living for a sex-changing, potentially protogynous coral reef fish, the Ambon damselfish, Pomacentrus amboinensis. Extensive sampling showed that the species exhibits resource defence polygyny, where dominant males guard a nest site that is visited by females. P. amboinensis have a longevity of about 6.5 years on the northern Great Barrier Reef. While the species can change sex consistent with being a protogynous hermaphrodite, it is unclear the extent to which the species uses this capability. Social groups are comprised of one reproductive male, 1-7 females and a number of juveniles. Females live in a linear dominance hierarchy, with the male being more aggressive to the beta-female than the alpha-female, who exhibits lower levels of ovarian cortisol. Surveys and a tagging study indicated that groups were stable for at least three months. A passive integrated transponder tag study showed that males spawn with females from their own group, but also females from neighbouring groups. In situ behavioural observations found that alpha-females have priority of access to the nest site that the male guarded, and access to higher quality foraging areas. Male removal studies suggest that the alpha-females can change sex to take over from the male when the position becomes available. Examination of otolith microstructure showed that those individuals which change sex to males have different embryonic characteristics at hatching, suggesting that success may involve a component that is parentally endowed. The relative importance of parental effects and social organisation in affecting the importance of female queuing is yet to be studied, but will likely depend on the strength of social

Physiological Plasticity to Water Flow Habitat in the Damselfish, Acanthochromis polyacanthus: Linking Phenotype to Performance

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Binning, Sandra A.; Ros, Albert F. H.; Nusbaumer, David; Roche, Dominique G.

2015-01-01

The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology. PMID:25807560

Growth effect on liver fatty acid composition of damselfishes genus Abudefduf collected in coral reef habitats of the Malaysian South China Sea.

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Arai, Takaomi; Amalina, Razikin; Bachok, Zainudin

2015-01-01

In order to understand feeding ecology, habitat use and migration of coral reef fish, fatty acid composition was examined in damselfish species Abudefduf bengalensis and A. sexfasciatus collected in the Malaysian South China Sea. Proportions of saturated fatty acids (SAFA) ranged from 49.5% to 74.2%, with the highest proportions in fatty acids, the second highest was monounsaturated fatty acids (MUFA) ranged from 21.4% to 47.4% and the proportion of polyunsaturated fatty acids (PUFA) was the lowest ranged from 3.1% to 6.0%. Palmitic acid (16:0) was the most common in SAFA, oleic acid (C18:1ω9c) was the dominant in MUFA and linolenic acid (C18:3n3) showed the highest proportion in PUFA. Fatty acid concentrations, especially in SAFA and MUFA, could be related to physiological condition, sexual development, and recent feeding events. The diet shift revealed by the fatty acid composition suggests changes in habitat use and migration scale in coral reef environment of genus Abudefduf.

Existence of a photoinducible phase for ovarian development and photoperiod-related alteration of clock gene expression in a damselfish.

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Takeuchi, Yuki; Hada, Noriko; Imamura, Satoshi; Hur, Sung-Pyo; Bouchekioua, Selma; Takemura, Akihiro

2015-10-01

The sapphire devil, Chrysiptera cyanea, is a reef-associated damselfish and their ovarian development can be induced by a long photoperiod. In this study, we demonstrated the existence of a photoinducible phase for the photoperiodic ovarian development in the sapphire devil. Induction of ovarian development under night-interruption light schedules and Nanda-Hamner cycles revealed that the photoinducible phase appeared in a circadian manner between ZT12 and ZT13. To characterize the effect of photoperiod on clock gene expression in the brain of this species, we determined the expression levels of the sdPer1, sdPer2, sdCry1, and sdCry2 clock genes under constant light and dark conditions (LL and DD) and photoperiodic (short and long photoperiods). The expression of sdPer1 exhibited clear circadian oscillation under both LL and DD conditions, while sdPer2 and sdCry1 expression levels were lower under DD than under LL conditions and sdCry2 expression was lower under LL than under DD conditions. These results suggest a key role for sdPer1 in circadian clock cycling and that sdPer2, sdCry1, and sdCry2 are light-responsive clock genes in the sapphire devil. After 1 week under a long photoperiod, we observed photoperiod-related changes in sdPer1, sdPer2, and sdCry2 expression, but not in sdCry1 expression. These results suggest that the expression patterns of some clock genes exhibit seasonal variation according to seasonal changes in day length and that such seasonal alteration of clock gene expression may contribute to seasonal recognition by the sapphire devil. Copyright © 2015 Elsevier Inc. All rights reserved.

Consumption of coral propagules after mass spawning enhances larval quality of damselfish through maternal effects.

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McCormick, Mark I

2003-06-01

The synchronized spawning of corals in many parts of the Indo-Pacific represents a huge injection of biological material into the waters around reefs. Much of this material is consumed by fishes and filter-feeding invertebrates in the 5 or so days following spawning. The present study is the first to document the effect of the consumption of coral propagules on a population of facultatively planktivorous fish and the transference of physiological condition across generations. The study compares two populations of the damselfish Pomacentrus amboinensis that fed to differing degrees on coral propagules for 5 days after the annual mass spawning of corals at Lizard Island, Great Barrier Reef, Australia. Wind blew coral slicks over the outer lagoon to the inner lagoon some 1.5 km away. While coral propagules were abundant in the water column in the windward location, they were scarce by the time the water mass reached the inner lagoon. Behavioral observations 2-5 days after coral spawning showed that a significantly higher proportion of P. amboinensis was feeding on coral propagules in the windward location than in the inner lagoon location. Windward location females consumed coral propagules almost exclusively and had fuller guts than females from the inner lagoonal location. Five days after the mass coral spawning, windward location females had a higher condition factor and a larger liver mass relative to body mass compared to females within the inner lagoon or females from both locations 2 months later. Fish eggs laid by the windward location females soon after coral spawning yielded larvae that had 25% larger yolk sacs and 100% larger oil globules than did larvae produced from the females from the inner lagoon location, or larvae produced at either location prior to or well after coral spawning in 2 previous years. Larger yolk sacs and oil globules have been shown to have direct survival benefits in the transition from endogenous to exogenous feeding. A feeding

On the misidentification of a common sandy beach crab belonging to ...

African Journals Online (AJOL)

1992-07-09

Jul 9, 1992 ... three-spot swimming crab, a member of the genus Ovalipes. Rathbun, 1898. Members ... coastal and estuarine waters of temperate oceans and are especially .... salinity and temperature tolerances of its zoeae. S. Afr. J. Zool.

50 CFR 665.421 - Definitions.

Science.gov (United States)

2010-10-01

.... harlequin tuskfish, red-breasted wrasse Cheilinus fasciatus. ring-tailed wrasse Oxycheilinus unifasciatus... margaritacous. three-spot wrasse Halichoeres trimaculatus. surge wrasse Thalassoma purpureum. red ribbon wrasse... javanicus. undulated moray eel Gymnothorax undulatus. Octopodidae (Octopus) gamsun octopus Octopus cyanea...

Distribution of the portunid crab Ova/ipes punctatus (De Haan) in ...

African Journals Online (AJOL)

(De Haan) in Algoa Bay and salinity and temperature tolerances of its ... The three-spot swimming crab Ovalipes punctatus is commonly found in surf zones off ..... recorded in the Sundays River or Swartkops River estuaries. (p.E.D. Winter and ...

An endoparasitic trichodinid (Ciliophora: Peritrichia) from the urinary ...

African Journals Online (AJOL)

1988-09-07

Sep 7, 1988 ... During parasitological surveys in Gazankulu, an infection of a trichodinid peritrich was found in the urinary bladder and ureters of the three-spot barb, Barbus trimaculatus Peters, 1852, collected from Hudson-. Ntsanwisi Dam in the Olifants River system. A taxonomic description of this new species, ...

Compensatory immigration depends on adjacent population size and habitat quality but not on landscape connectivity.

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Turgeon, Katrine; Kramer, Donald L

2012-11-01

1. Populations experiencing localized mortality can recover in the short term by net movement of individuals from adjacent areas, a process called compensatory immigration or spillover. Little is known about the factors influencing the magnitude of compensatory immigration or its impact on source populations. Such information is important for understanding metapopulation dynamics, the use of protected areas for conservation, management of exploited populations and pest control. 2. Using two small, territorial damselfish species (Stegastes diencaeus and S. adustus) in their naturally fragmented habitat, we quantified compensatory immigration in response to localized mortality, assessed its impact on adjacent source populations and examined the importance of potential immigrants, habitat quality and landscape connectivity as limiting factors. On seven experimental sites, we repeatedly removed 15% of the initial population size until none remained and immigration ceased. 3. Immigrants replaced 16-72% of original residents in S. diencaeus and 0-69% in S. adustus. The proportion of the source population that immigrated into depleted areas varied from 9% to 61% in S. diencaeus and from 3% to 21% in S. adustus. In S. diencaeus, compensatory immigration was strongly affected by habitat quality, to a lesser extent by the abundance of potential immigrants and not by landscape connectivity. In S. adustus, immigration was strongly affected by the density of potential migrants and not by habitat quality and landscape connectivity. On two control sites, immigration in the absence of creation of vacancies was extremely rare. 4. Immigration occurred in response to localized mortality and was therefore compensatory. It was highly variable, sometimes producing substantial impacts on both depleted and source populations. The magnitude of compensatory immigration was influenced primarily by the availability of immigrants and by the potential improvement in territory quality that they

Comunidad de parásitos metazoarios de la charra Cichlasoma trimaculatum en la laguna de Tres Palos, Guerrero, México Metazoan parasite community in the three-spot cichlid Cichlasoma trimaculatum from Tres Palos Lagoon, Guerrero, Mexico

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Juan Violante-González

2008-12-01

Full Text Available Entre abril de 2000 y noviembre de 2002 se examinó la composición de la comunidad de parásitos metazoarios de la charra, Cichlasoma trimaculatum a partir de muestras temporales. Fueron recuperadas 12 especies de parásitos (40 969 individuos de 231 hospederos examinados; 10 helmintos: Ascocotyle (Phagicola longa, Austrodiplostomum compactum, Cladocystis trifolium, Clinostomum complanatum, Crassicutis cichlasomae, Posthodiplostomum minimum, Pseudoacanthostomum panamense, Neoechinorhynchus golvani, Southwellina hispida y Contracaecum sp., y 2 crustáceos: Argulus sp. y Ergasilus sp. La comunidad se caracterizó por un número mayor de parásitos generalistas y pocos especialistas de cíclidos, además por ser pobre en especies. De las 5 especies comunes dentro de la comunidad, 4 presentaron variación temporal en su dinámica de infección a lo largo del tiempo, la cual fue asociada con cambios ambientales generados durante las temporadas de secas y lluvias. La variación en la dinámica de infección de las especies comunes fue capaz de generar cambios en la estructura, tanto en el nivel de componente como en el de infracomunidad; sin embargo, no se observó un patrón claro, lo que indica que la comunidad puede ser poco predecible, como se sugiere para otras comunidades de parásitos de peces dulceacuícolas.We analyzed metazoan parasite community composition in the three-spot cichlid Cichlasoma trimaculatum using seasonal samples taken between April 2000 and November 2002 from the Tres Palos Lagoon, Guerrero, Mexico. A total of 231 hosts were examined. Of the 12 parasite species recovered (40,969 individuals, 10 were helminths: Ascocotyle (Phagicola longa, Austrodiplostomum compactum, Cladocystis trifolium, Clinostomum complanatum, Crassicutis cichlasomae, Posthodiplostomum minimum, Pseudoacanthostomum panamense, Neoechinorhynchus golvani, Southwellina hispida, and Contracaecum sp. The remaining 2 were the crustaceans Argulus sp. and

Expression profile of doublesex/male abnormal-3-related transcription factor-1 during gonadal sex change in the protogynous wrasse, Halichoeres trimaculatus.

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Nozu, Ryo; Horiguchi, Ryo; Kobayashi, Yasuhisa; Nakamura, Masaru

2015-11-01

Sex change in fish involves a dramatic transformation of gonadal tissue and a switch in gametogenesis. Doublesex/male abnormal-3-related transcription factor-1 (DMRT1), encoded by the DMRT1 gene, is involved in testicular differentiation in a wide range of vertebrates as well as in sexual differentiation and gonadal sex change. In the present study, we investigated changes in the expression of dmrt1 during artificial gonadal sex change in the three-spot wrasse, Halichoeres trimaculatus, by real-time quantitative PCR and immunolocalization, using an anti-wrasse-Dmrt1 antibody that we prepared. We found that dmrt1 expression was predominantly observed in the testes, and that Dmrt1 was expressed in Sertoli cells of testes and a few granulosa cells surrounding vitellogenic oocytes of the ovary. Additionally, the upregulation of dmrt1 expression was consistent with an increase in spermatogenic cyst quantity rather than proliferation of presumptive spermatogonia, suggesting that dmrt1 is involved in the progression of spermatogenesis during sex change. Changes in the localization of Dmrt1 during gonadal sex change further implied that Sertoli cells originate from somatic cells adjacent to gonial germ cells during testicular formation in the three-spot wrasse. © 2015 Wiley Periodicals, Inc.

Territorial hypothesis predicts the trade-off between reproductive opportunities and parental care in three species of damselfishes (Pomacentridae: Actinopterygii La hipótesis territorial predice la compensación entre las oportunidades reproductivas y el cuidado parental en tres especies de peces damisela (Pomacentridae: Actinopterygii

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Eduardo Bessa

2012-03-01

Full Text Available Paternal care is rare in most animals, but common in fishes, including Pomacentridae. One way of explaining it is through the territorial hypothesis, which predicts that paternal care may evolve when caring for a territory with eggs will not cost more than territories without eggs. Here we describe the reproductive behavior of three pomacentrids from São Paulo, Brazil, and evaluate if the territorial hypothesis explains their behavioral variation through five predictions. We checked if females have multiple spawns (prediction 1, if they forage more (prediction 2 and if territory defence demands more when eggs are present (prediction 3. We also described how visible eggs are (prediction 4 and how available nesting sites are (prediction 5. Chromis multilineata differed from Abudefduf saxatilis and Stegastes fuscus by not guarding the eggs, spending less time with territoriality and fanning eggs; and more time feeding and foraging. Females of the three species are iteroparous. Females' A. saxatilis and S. fuscus foraged more than males, which spent the same amount of time in territorial defence before and after eggs were delivered. These two species also have very conspicuous egg clutches on clean rock surfaces defended by them. On the other hand, males and females of C. multilineata spent the same time foraging, while territoriality took more effort after eggs were present and it spawns cryptic eggs amid Sargassum, a common and disperse micro-environment in São Paulo rocky shores. Territorial hypothesis explains why paternal care by A. saxatilis and S. fuscus lasts longer than by C. multilineata.El cuidado paterno es raro en la mayoría de los animales, pero común en los peces, incluyendo los Pomacentridae. Una forma de explicar este fenómeno es la hipótesis territorial, que predice que el cuidado paterno puede evolucionar cuando la protección de un territorio con huevos no cuesta más que la de territorios sin huevos. Aquí se describe el

Putting prey and predator into the CO2 equation--qualitative and quantitative effects of ocean acidification on predator-prey interactions.

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Ferrari, Maud C O; McCormick, Mark I; Munday, Philip L; Meekan, Mark G; Dixson, Danielle L; Lonnstedt, Öona; Chivers, Douglas P

2011-11-01

Little is known about the impact of ocean acidification on predator-prey dynamics. Herein, we examined the effect of carbon dioxide (CO(2)) on both prey and predator by letting one predatory reef fish interact for 24 h with eight small or large juvenile damselfishes from four congeneric species. Both prey and predator were exposed to control or elevated levels of CO(2). Mortality rate and predator selectivity were compared across CO(2) treatments, prey size and species. Small juveniles of all species sustained greater mortality at high CO(2) levels, while large recruits were not affected. For large prey, the pattern of prey selectivity by predators was reversed under elevated CO(2). Our results demonstrate both quantitative and qualitative consumptive effects of CO(2) on small and larger damselfish recruits respectively, resulting from CO(2)-induced behavioural changes likely mediated by impaired neurological function. This study highlights the complexity of predicting the effects of climate change on coral reef ecosystems. © 2011 Blackwell Publishing Ltd/CNRS.

Lethal effects of habitat degradation on fishes through changing competitive advantage.

Science.gov (United States)

McCormick, Mark I

2012-10-07

Coral bleaching has caused catastrophic changes to coral reef ecosystems around the world with profound ecological, social and economic repercussions. While its occurrence is predicted to increase in the future, we have little understanding of mechanisms that underlie changes in the fish community associated with coral degradation. The present study uses a field-based experiment to examine how the intensity of interference competition between juveniles of two species of damselfish changes as healthy corals degrade through thermal bleaching. The mortality of a damselfish that is a live coral specialist (Pomacentrus moluccensis) increased on bleached and dead coral in the presence of the habitat generalist (Pomacentrus amboinensis). Increased mortality of the specialist was indirectly owing to enhanced aggression by the generalist forcing the specialist higher up and further away from shelter on bleached and dead coral. Evidence from this study stresses the importance of changing interspecific interactions to community dynamics as habitats change.

Effects of season, sex and body size on the feeding ecology of turtle-headed sea snakes ( Emydocephalus annulatus) on IndoPacific inshore coral reefs

Science.gov (United States)

Goiran, C.; Dubey, S.; Shine, R.

2013-06-01

In terrestrial snakes, many cases of intraspecific shifts in dietary habits as a function of predator sex and body size are driven by gape limitation and hence are most common in species that feed on relatively large prey and exhibit a wide body-size range. Our data on sea snakes reveal an alternative mechanism for intraspecific niche partitioning, based on sex-specific seasonal anorexia induced by reproductive activities. Turtle-headed sea snakes ( Emydocephalus annulatus) on coral reefs in the New Caledonian Lagoon feed entirely on the eggs of demersal-spawning fishes. DNA sequence data (cytochrome b gene) on eggs that we palpated from stomachs of 37 snakes showed that despite this ontogenetic stage specialization, the prey comes from a taxonomically diverse array of species including damselfish (41 % of samples, at least 5 species), blennies (41 %, 4 species) and gobies (19 %, 5 species). The composition of snake diets shifted seasonally (with damselfish dominating in winter but not summer), presumably reflecting seasonality of fish reproduction. That seasonal shift affects male and female snakes differently, because reproduction is incompatible with foraging. Adult female sea snakes ceased feeding when they became heavily distended with developing embryos in late summer, and males ceased feeding while they were mate searching in winter. The sex divergence in foraging habits may be amplified by sexual size dimorphism; females grow larger than males, and larger snakes (of both sexes) feed more on damselfish (which often lay their eggs in exposed sites) than on blennies and gobies (whose eggs are hidden within narrow crevices). Specific features of reproductive biology of coral reef fish (seasonality and nest type) have generated intraspecific niche partitioning in these sea snakes, by mechanisms different from those that apply to terrestrial snakes.

Effects of ocean acidification on learning in coral reef fishes.

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Maud C O Ferrari

Full Text Available Ocean acidification has the potential to cause dramatic changes in marine ecosystems. Larval damselfish exposed to concentrations of CO(2 predicted to occur in the mid- to late-century show maladaptive responses to predator cues. However, there is considerable variation both within and between species in CO(2 effects, whereby some individuals are unaffected at particular CO(2 concentrations while others show maladaptive responses to predator odour. Our goal was to test whether learning via chemical or visual information would be impaired by ocean acidification and ultimately, whether learning can mitigate the effects of ocean acidification by restoring the appropriate responses of prey to predators. Using two highly efficient and widespread mechanisms for predator learning, we compared the behaviour of pre-settlement damselfish Pomacentrus amboinensis that were exposed to 440 µatm CO(2 (current day levels or 850 µatm CO(2, a concentration predicted to occur in the ocean before the end of this century. We found that, regardless of the method of learning, damselfish exposed to elevated CO(2 failed to learn to respond appropriately to a common predator, the dottyback, Pseudochromis fuscus. To determine whether the lack of response was due to a failure in learning or rather a short-term shift in trade-offs preventing the fish from displaying overt antipredator responses, we conditioned 440 or 700 µatm-CO(2 fish to learn to recognize a dottyback as a predator using injured conspecific cues, as in Experiment 1. When tested one day post-conditioning, CO(2 exposed fish failed to respond to predator odour. When tested 5 days post-conditioning, CO(2 exposed fish still failed to show an antipredator response to the dottyback odour, despite the fact that both control and CO(2-treated fish responded to a general risk cue (injured conspecific cues. These results indicate that exposure to CO(2 may alter the cognitive ability of juvenile fish and render

Algal growth and species composition under experimental control of herbivory, phosphorus and coral abundance in Glovers Reef, Belize.

Science.gov (United States)

McClanahan, T R; Cokos, B A; Sala, E

2002-06-01

The proliferation of algae on disturbed coral reefs has often been attributed to (1) a loss of large-bodied herbivorous fishes, (2) increases in sea water nutrient concentrations, particularly phosphorus, and (3) a loss of hard coral cover or a combination of these and other factors. We performed replicated small-scale caging experiments in the offshore lagoon of Glovers Reef atoll, Belize where three treatments had closed-top (no large-bodied herbivores) and one treatment had open-top cages (grazing by large-bodied herbivores). Closed-top treatments simulated a reduced-herbivory situation, excluding large fishes but including small herbivorous fishes such as damselfishes and small parrotfishes. Treatments in the closed-top cages included the addition of high phosphorus fertilizer, live branches of Acropora cervicornis and a third unmanipulated control treatment. Colonization, algal biomass and species composition on dead A. palmata "plates" were studied weekly for 50 days in each of the four treatments. Fertilization doubled the concentration of phosphorus from 0.35 to 0.77 microM. Closed-top cages, particularly the fertilizer and A. cervicornis additions, attracted more small-bodied parrotfish and damselfish than the open-top cages such that there was moderate levels of herbivory in closed-top cages. The open-top cages did, however, have a higher abundance of the chemically and morphologically defended erect algal species including Caulerpa cupressoides, Laurencia obtusa, Dictyota menstrualis and Lobophora variegata. The most herbivore-resistant calcareous green algae (i.e. Halimeda) were, however, uncommon in all treatments. Algal biomass increased and fluctuated simultaneously in all treatments over time, but algal biomass, as measured by wet, dry and decalcified weight, did not differ greatly between the treatments with only marginally higher biomass (p reefs except for creating space. In contrast, A. cervicornis appears to attract aggressive damselfish that

Extended exposure to elevated temperature affects escape response behaviour in coral reef fishes

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Donald T. Warren

2017-08-01

Full Text Available The threat of predation, and the prey’s response, are important drivers of community dynamics. Yet environmental temperature can have a significant effect on predation avoidance techniques such as fast-start performance observed in marine fishes. While it is known that temperature increases can influence performance and behaviour in the short-term, little is known about how species respond to extended exposure during development. We produced a startle response in two species of damselfish, the lemon damsel Pomacentrus moluccensis, and the Ambon damselfish Pomacentrus amboinensis, by the repeated use of a drop stimulus. We show that the length of thermal exposure of juveniles to elevated temperature significantly affects this escape responses. Short-term (4d exposure to warmer temperature affected directionality and responsiveness for both species. After long-term (90d exposure, only P. moluccensis showed beneficial plasticity, with directionality returning to control levels. Responsiveness also decreased in both species, possibly to compensate for higher temperatures. There was no effect of temperature or length of exposure on latency to react, maximum swimming speed, or escape distance suggesting that the physical ability to escape was maintained. Evidence suggests that elevated temperature may impact some fish species through its effect on the behavioural responses while under threat rather than having a direct influence on their physical ability to perform an effective escape response.

Effects of elevated CO2 on predator avoidance behaviour by reef fishes is not altered by experimental test water

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Philip L. Munday

2016-10-01

Full Text Available Pioneering studies into the effects of elevated CO2 on the behaviour of reef fishes often tested high-CO2 reared fish using control water in the test arena. While subsequent studies using rearing treatment water (control or high CO2 in the test arena have confirmed the effects of high CO2 on a range of reef fish behaviours, a further investigation into the use of different test water in the experimental arena is warranted. Here, we used a fully factorial design to test the effect of rearing treatment water (control or high CO2 and experimental test water (control or high CO2 on antipredator responses of larval reef fishes. We tested antipredator behaviour in larval clownfish Amphiprion percula and ambon damselfish Pomacentrus amboinensis, two species that have been used in previous high CO2 experiments. Specifically, we tested if: (1 using control or high CO2 water in a two channel flume influenced the response of larval clownfish to predator odour; and (2 using control or high CO2 water in the test arena influenced the escape response of larval damselfish to a startle stimulus. Finally, (3 because the effects of high CO2 on fish behaviour appear to be caused by altered function of the GABA-A neurotransmitter we tested if antipredator behaviours were restored in clownfish treated with a GABA antagonist (gabazine in high CO2 water. Larval clownfish reared from hatching in control water (496 µatm strongly avoided predator cue whereas larval clownfish reared from hatching in high CO2 (1,022 µatm were attracted to the predator cue, as has been reported in previous studies. There was no effect on fish responses of using either control or high CO2 water in the flume. Larval damselfish reared for four days in high CO2 (1,051 µatm exhibited a slower response to a startle stimulus and slower escape speed compared with fish reared in control conditions (464 µatm. There was no effect of test water on escape responses. Treatment of high-CO2 reared

Fitness consequences of habitat variability, trophic position, and energy allocation across the depth distribution of a coral-reef fish

Science.gov (United States)

Goldstein, E. D.; D'Alessandro, E. K.; Sponaugle, S.

2017-09-01

Environmental clines such as latitude and depth that limit species' distributions may be associated with gradients in habitat suitability that can affect the fitness of an organism. With the global loss of shallow-water photosynthetic coral reefs, mesophotic coral ecosystems ( 30-150 m) may be buffered from some environmental stressors, thereby serving as refuges for a range of organisms including mobile obligate reef dwellers. Yet habitat suitability may be diminished at the depth boundary of photosynthetic coral reefs. We assessed the suitability of coral-reef habitats across the majority of the depth distribution of a common demersal reef fish ( Stegastes partitus) ranging from shallow shelf (SS, restrict foraging. Fish in MP environments had a broader diet niche, higher trophic position, and higher muscle C:N ratios compared to shallower environments. High C:N ratios suggest increased tissue lipid content in fish in MP habitats that coincided with higher investment in reproduction based on gonado-somatic index. These results suggest that peripheral MP reefs are suitable habitats for demersal reef fish and may be important refuges for organisms common on declining shallow coral reefs.

SPECTRAL AND SPATIAL SELECTIVITY OF LUMINANCE VISION IN REEF FISH

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Ulrike E Siebeck

2014-09-01

Full Text Available Luminance vision has high spatial resolution and is used for form vision and texture discrimination. In humans, birds and bees luminance channel is spectrally selective – it depends on the signals of the long-wavelength sensitive photoreceptors (bees or on the sum of long- and middle- wavelength sensitive cones (humans, but not on the signal of the short-wavelength sensitive (blue photoreceptors. The reasons of such selectivity are not fully understood. The aim of this study is to reveal the inputs of cone signals to high resolution luminance vision in reef fish. 16 freshly caught damselfish, Pomacentrus amboinensis, were trained to discriminate stimuli differing either in their colour or in their fine patterns (stripes vs. cheques. Three colours (‘bright green’, ‘dark green’ and ‘blue’ were used to create two sets of colour and two sets of pattern stimuli. The ‘bright green’ and ‘dark green’ were similar in their chromatic properties for fish, but differed in their lightness; the ‘dark green’ differed from ‘blue’ in the signal for the blue cone, but yielded similar signals in the long-wavelength and middle-wavelength cones. Fish easily learned to discriminate ‘bright green’ from ‘dark green’ and ‘dark green’ from ‘blue’ stimuli. Fish also could discriminate the fine patterns created from ‘dark green’ and ‘bright green’. However, fish failed to discriminate fine patterns created from ‘blue’ and ‘dark green’ colours, i.e. the colours that provided contrast for the blue-sensitive photoreceptor, but not for the long-wavelength sensitive one. High resolution luminance vision in damselfish, Pomacentrus amboinensis, does not have input from the blue-sensitive cone, which may indicate that the spectral selectivity of luminance channel is a general feature of visual processing in both aquatic and terrestrial animals.

Cleaning interactions by gobies on a tropical eastern Pacific coral reef.

Science.gov (United States)

Quimbayo, J P; Zapata, F A

2018-04-01

The present study describes the cleaning interactions among species of cleaner gobies Tigrigobius spp. and Elacatinus puncticulatus (family Gobiidae) and the client fish species they clean in a coral reef of Gorgona Island, Colombia. In 419 cleaning events, we observed 27 species acting as clients of Tigrigobius spp., whereas only nine were clients of E. puncticulatus. Paranthias colonus and Cephalopholis panamensis were the species most commonly cleaned by Tigrigobius spp., while Ophioblennius steindachneri and Stegastes acalpulcoensis were the clients most commonly cleaned by E. puncticulatus. The abundance (but not the body size) of clients was an important variable predicting the cleaning frequency observed for clients of Tigrigobius spp., but this was not the case for clients of E. puncticulatus. Additionally, Tigrigobius spp. preferred cleaning planktivores, sessile invertebrate feeders and territorial herbivores (Ivlev's index >0·15), whereas E. puncticulatus did not exhibit any preference. We observed two major peaks of cleaning activity for Tigrigobius spp., one in the early morning and another one in the late afternoon. These results suggest that Tigrigobius spp. is a specialized cleaner goby, whereas E. puncticulatus is a facultative cleaner that cleans sporadically. © 2018 The Fisheries Society of the British Isles.

Coral reef fish predator maintains olfactory acuity in degraded coral habitats.

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Michael Natt

Full Text Available Coral reefs around the world are rapidly degrading due to a range of environmental stressors. Habitat degradation modifies the sensory landscape within which predator-prey interactions occur, with implications for olfactory-mediated behaviours. Predator naïve settlement-stage damselfish rely on conspecific damage-released odours (i.e., alarm odours to inform risk assessments. Yet, species such as the Ambon damselfish, Pomacentrus amboinensis, become unable to respond appropriately to these cues when living in dead-degraded coral habitats, leading to increased mortality through loss of vigilance. Reef fish predators also rely on odours from damaged prey to locate, assess prey quality and engage in prey-stealing, but it is unknown whether their responses are also modified by the change to dead-degraded coral habitats. Implications for prey clearly depend on how their predatory counterparts are affected, therefore the present study tested whether olfactory-mediated foraging responses in the dusky dottyback, Pseudochromis fuscus, a common predator of P. amboinensis, were similarly affected by coral degradation. A y-maze was used to measure the ability of Ps. fuscus to detect and move towards odours, against different background water sources. Ps. fuscus were exposed to damage-released odours from juvenile P. amboinensis, or a control cue of seawater, against a background of seawater treated with either healthy or dead-degraded hard coral. Predators exhibited an increased time allocation to the chambers of y-mazes injected with damage-released odours, with comparable levels of response in both healthy and dead-degraded coral treated waters. In control treatments, where damage-released odours were replaced with a control seawater cue, fish showed no increased preference for either chamber of the y-maze. Our results suggest that olfactory-mediated foraging behaviours may persist in Ps. fuscus within dead-degraded coral habitats. Ps. fuscus may

First report of scuticociliatosis caused by Uronema sp. in ornamental reef fish imported into Brazil

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Pedro Henrique Magalhães Cardoso

Full Text Available Abstract Scuticociliatosis, which is caused by an opportunistic ciliate protozoan, is responsible for significant economic losses in marine ornamental fish. This study reports the occurrence of Uronema sp., which was found to be parasitizing three species of marine reef fish imported into Brazil and maintained in quarantine: Vanderbilt’s Chromis (Chromis vanderbilti, blue-green damselfish (Chromis viridis, and sea goldie (Pseudanthias squamipinnis. During the quarantine period, some fish presented with behavioral disorders and hemorrhages and ulcerative lesions on the body surface. Histopathological analysis showed hemorrhages, inflammation comprising mononuclear and granular cells in the skeletal muscle, and necrosis of the skin and the secondary lamellae of the gills, and parasites were also observed in the renal capsule. The absence of transboundary measures available to prevent the occurrence of ornamental fish diseases is also discussed.

Otolith growth of Springer's demoiselle, Chrysiptera springeri (Pomacentridae, Allen & Lubbock), on a protected and non-protected coral reef

DEFF Research Database (Denmark)

Retzel, A.; Hansen, A.D.; Grønkjær, P.

2007-01-01

The structural complexity of coral reefs is important for their function as shelter and feeding habitats for coral reef fishes, but physical disturbance by human activities often reduce complexity of the reefs by selectively destroying fragile and more complex coral species. The damselfish Springer......'s demoiselle Chrysiptera springeri primarily utilize complex coral heads for shelter and are hence vulnerable to human disturbance. In order to evaluate the potential effect of habitat degradation on juvenile fish growth, coral reef cover, fish age at settling and otolith growth, juvenile Springer's demoiselle...... was investigated on a protected and non-protected coral reef in Darvel Bay, Borneo. The protected reef had higher coverage of complex branching corals and exhibited a more complex 3-dimensional structure than the non-protected reef. Springer's demoiselle settled at the same age on non-protected and protected reefs...

Effects of Nautical Traffic and Noise on Foraging Patterns of Mediterranean Damselfish (Chromis chromis)

Science.gov (United States)

Bracciali, Claudia; Campobello, Daniela; Giacoma, Cristina; Sarà, Gianluca

2012-01-01

Chromis chromis is a key species in the Mediterranean marine coastal ecosystems where, in summer, recreational boating and its associated noise overlap. Anthropogenic noise could induce behavioural modifications in marine organisms, thereby affecting population dynamics. In the case of an important species for the ecosystem like C. chromis, this could rebound on the community structure. Here, we measured nautical traffic during the summer of 2007 in a Southern Mediterranean Marine Protected Area (MPA) and simultaneously the feeding behaviour of C. chromis was video-recorded, within both the no-take A-zone and the B-zone where recreational use is allowed. Feeding frequencies, escape reaction and school density were analysed. C. chromis specimens were also collected from 2007 to 2008 to evaluate their physiological state using the Body Condition Index as a proxy of feeding efficiency. The MPA was more exploited by nautical tourism during holidays than on weekdays, particularly in the middle of the day. Greater traffic volume corresponded with lower feeding frequencies. The escape reaction was longer in duration (>1 min) when boat passed nearby, while moored boats did not induce an escape response. We found no differences in density between schools in the A- and B-zones and worse body conditions among those individuals inhabiting the B-zone in one area only. Overall, our findings revealed a significant modification of the daily foraging habits of C. chromis due to boat noise, which was slightly buffered by no-take zones established within the MPA. PMID:22792375

Temporal constraints on predation risk assessment in a changing world

International Nuclear Information System (INIS)

Chivers, Douglas P.; Ramasamy, Ryan A.; McCormick, Mark I.; Watson, Sue-Ann; Siebeck, Ulrike E.; Ferrari, Maud C.O.

2014-01-01

Habitat degradation takes various forms and likely represents the most significant threat to our global biodiversity. Recently, we have seen considerable attention paid to increasing global CO 2 emissions which lead to ocean acidification (OA). Other stressors, such as changing levels of ultraviolet radiation (UVR), also impact biodiversity but have received much less attention in the recent past. Here we examine fundamental questions about temporal aspects of risk assessment by coral reef damselfish and provide critical insights into how OA and UVR influence this assessment. Chemical cues released during a predator attack provide a rich source of information that other prey animals use to mediate their risk of predation and are the basis of the majority of trait-mediated indirect interactions in aquatic communities. However, we have surprisingly limited information about temporal aspects of risk assessment because we lack knowledge about how long chemical cues persist after they are released into the environment. Here, we showed that under ambient CO 2 conditions (∼ 385 μatm), alarm cues of ambon damselfish (Pomacentrus amboinensis) did not degrade within 30 min in the absence of ultraviolet radiation (UVR), but were degraded within 15 min when the CO 2 was increased to ∼ 905 μatm. In experiments that used filters to eliminate UVR, we found minimal degradation of alarm cues within 30 min, whereas under ambient UVR conditions, alarm cues were completely degraded within 15 min. Moreover, in the presence of both UVR and elevated CO 2 , alarm cues were broken down within 5 min. Our results highlight that alarm cues degrade surprisingly quickly under natural conditions and that anthropogenic changes have the potential to dramatically change rates of cue degradation in the wild. This has considerable implications for risk assessment and consequently the importance of trait-mediated indirect interactions in coral-reef communities. - Highlights: • We have limited

Soundscapes from a Tropical Eastern Pacific reef and a Caribbean Sea reef

Science.gov (United States)

Staaterman, E.; Rice, A. N.; Mann, D. A.; Paris, C. B.

2013-06-01

Underwater soundscapes vary due to the abiotic and biological components of the habitat. We quantitatively characterized the acoustic environments of two coral reef habitats, one in the Tropical Eastern Pacific (Panama) and one in the Caribbean (Florida Keys), over 2-day recording durations in July 2011. We examined the frequency distribution, temporal variability, and biological patterns of sound production and found clear differences. The Pacific reef exhibited clear biological patterns and high temporal variability, such as the onset of snapping shrimp noise at night, as well as a 400-Hz daytime band likely produced by damselfish. In contrast, the Caribbean reef had high sound levels in the lowest frequencies, but lacked clear temporal patterns. We suggest that acoustic measures are an important element to include in reef monitoring programs, as the acoustic environment plays an important role in the ecology of reef organisms at multiple life-history stages.

The effect of adult aggression on habitat selection by settlers of two coral-dwelling damselfishes.

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Ofer Ben-Tzvi

Full Text Available Coral-reef fishes experience a major challenge when facing settlement in a multi-threat environment, within which, using settlement cues, they need to select a suitable site. Studies in laboratories and artificial setups have shown that the presence of conspecific adults often serves as a positive settlement cue, whose value is explained by the increased survival of juveniles in an already proven fit environment. However, settlement in already inhabited corals may expose the recruits to adult aggression. Daily observations and manipulation experiments were used in the present study, which was conducted in the natural reef. We revealed differential strategies of settlers, which do not necessarily join conspecific adults. Dascyllus aruanus prefer to settle near (not with their aggressive adults, and to join them only after gaining in size; whereas Dascyllus marginatus settlers in densely populated reefs settle independently of their adult distribution. Our results present different solutions to the challenges faced by fish recruits while selecting their microhabitat, and emphasize the complexity of habitat selection by the naïve settlers. Although laboratory experiments are important to the understanding of fish habitat selection, further studies in natural habitats are essential in order to elucidate the actual patterns of settlement and habitat selection, which are crucial for the survival of coral-reef fish populations.

Do otolith increments allow correct inferences about age and growth of coral reef fishes?

Science.gov (United States)

Booth, D. J.

2014-03-01

Otolith increment structure is widely used to estimate age and growth of marine fishes. Here, I test the accuracy of the long-term otolith increment analysis of the lemon damselfish Pomacentrus moluccensis to describe age and growth characteristics. I compare the number of putative annual otolith increments (as a proxy for actual age) and widths of these increments (as proxies for somatic growth) with actual tagged fish-length data, based on a 6-year dataset, the longest time course for a coral reef fish. Estimated age from otoliths corresponded closely with actual age in all cases, confirming annual increment formation. However, otolith increment widths were poor proxies for actual growth in length [linear regression r 2 = 0.44-0.90, n = 6 fish] and were clearly of limited value in estimating annual growth. Up to 60 % of the annual growth variation was missed using otolith increments, suggesting the long-term back calculations of otolith growth characteristics of reef fish populations should be interpreted with caution.

Novel life-history data for threatened seahorses provide insight into fishery effects.

Science.gov (United States)

Lawson, J M; Foster, S J; Lim, A C O; Chong, V C; Vincent, A C J

2015-01-01

Life-history variables for three incidentally captured species of seahorse (Kellogg's seahorse Hippocampus kelloggi, the hedgehog seahorse Hippocampus spinosissimus and the three-spot seahorse Hippocampus trimaculatus) were established using specimens obtained from 33 fisheries landing sites in Peninsular Malaysia. When samples were pooled by species across the peninsula, sex ratios were not significantly different from unity, and height and mass relationships were significant for all species. For two of these species, height at physical maturity (HM ) was smaller than the height at which reproductive activity (HR ) commenced: H. spinosissimus (HM = 99·6 mm, HR = 123·2 mm) and H. trimaculatus (HM = 90·5 mm, HR = 121·8 mm). For H. kelloggi, HM could not be estimated as all individuals were physically mature, while HR = 167·4 mm. It appears that all three Hippocampus spp. were, on average, caught before reproducing; height at 50% capture (HC ) was ≥HM but ≤HR . The results from this study probe the effectiveness of assessment techniques for data-poor fisheries that rely heavily on estimates of length at maturity, especially if maturity is poorly defined. Findings also question the sustainability of H. trimaculatus catches in the south-west region of Peninsular Malaysia, where landed specimens had a notably smaller mean height (86·2 mm) and markedly skewed sex ratio (6% males) compared with samples from the south-east and north-west of the peninsula. © 2014 The Fisheries Society of the British Isles.

Temporal constraints on predation risk assessment in a changing world

Energy Technology Data Exchange (ETDEWEB)

Chivers, Douglas P., E-mail: doug.chivers@usask.ca [Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5E2 (Canada); Ramasamy, Ryan A.; McCormick, Mark I.; Watson, Sue-Ann [ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville Qld4811 (Australia); School of Marine and Tropical Biology, James Cook University, Townsville Qld4811 (Australia); Siebeck, Ulrike E. [School of Biomedical Sciences, University of Queensland, Brisbane Qld4072 (Australia); Ferrari, Maud C.O. [Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK S7W 5B4 (Canada)

2014-12-01

Habitat degradation takes various forms and likely represents the most significant threat to our global biodiversity. Recently, we have seen considerable attention paid to increasing global CO{sub 2} emissions which lead to ocean acidification (OA). Other stressors, such as changing levels of ultraviolet radiation (UVR), also impact biodiversity but have received much less attention in the recent past. Here we examine fundamental questions about temporal aspects of risk assessment by coral reef damselfish and provide critical insights into how OA and UVR influence this assessment. Chemical cues released during a predator attack provide a rich source of information that other prey animals use to mediate their risk of predation and are the basis of the majority of trait-mediated indirect interactions in aquatic communities. However, we have surprisingly limited information about temporal aspects of risk assessment because we lack knowledge about how long chemical cues persist after they are released into the environment. Here, we showed that under ambient CO{sub 2} conditions (∼ 385 μatm), alarm cues of ambon damselfish (Pomacentrus amboinensis) did not degrade within 30 min in the absence of ultraviolet radiation (UVR), but were degraded within 15 min when the CO{sub 2} was increased to ∼ 905 μatm. In experiments that used filters to eliminate UVR, we found minimal degradation of alarm cues within 30 min, whereas under ambient UVR conditions, alarm cues were completely degraded within 15 min. Moreover, in the presence of both UVR and elevated CO{sub 2}, alarm cues were broken down within 5 min. Our results highlight that alarm cues degrade surprisingly quickly under natural conditions and that anthropogenic changes have the potential to dramatically change rates of cue degradation in the wild. This has considerable implications for risk assessment and consequently the importance of trait-mediated indirect interactions in coral-reef communities. - Highlights: �

CO2-induced ocean acidification does not affect individual or group behaviour in a temperate damselfish.

Science.gov (United States)

Kwan, Garfield Tsz; Hamilton, Trevor James; Tresguerres, Martin

2017-07-01

Open ocean surface CO 2 levels are projected to reach approximately 800 µatm, and ocean pH to decrease by approximately 0.3 units by the year 2100 due to anthropogenic CO 2 emissions and the subsequent process of ocean acidification (OA). When exposed to these CO 2 /pH values, several fish species display abnormal behaviour in laboratory tests, an effect proposed to be linked to altered neuronal GABA A- receptor function. Juvenile blacksmith ( Chromis punctipinnis ) are social fish that regularly experience CO 2 /pH fluctuations through kelp forest diurnal primary production and upwelling events, so we hypothesized that they might be resilient to OA. Blacksmiths were exposed to control conditions (pH ∼ 7.92; p CO 2  ∼ 540 µatm), constant acidification (pH ∼ 7.71; p CO 2  ∼ 921 µatm) and oscillating acidification (pH ∼ 7.91, p CO 2  ∼ 560 µatm (day), pH ∼ 7.70, p CO 2  ∼ 955 µatm (night)), and caught and tested in two seasons of the year when the ocean temperature was different: winter (16.5 ± 0.1°C) and summer (23.1 ± 0.1°C). Neither constant nor oscillating CO 2 -induced acidification affected blacksmith individual light/dark preference, inter-individual distance in a shoal or the shoal's response to a novel object, suggesting that blacksmiths are tolerant to projected future OA conditions. However, blacksmiths tested during the winter demonstrated significantly higher dark preference in the individual light/dark preference test, thus confirming season and/or water temperature as relevant factors to consider in behavioural tests.

Reef fish community in presence of the lionfish (Pterois volitans in Santa Marta, Colombian Caribbean

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Rocío García-Urueña

2015-11-01

Full Text Available Objective. Fish species community structure and benthic organisms coverage were studied in five localities in Santa Marta where the lionfish is present. Materials and methods. Abundance of fish species, including lion fish, was established using 30 m random visual censuses and video transects; trophic guilds were established according to available references. On the other hand benthic coverage was evaluated using the software Coral Point Count (CPCe 4.0. Results. Families with higher species numbers were Serranidae, Labridae, and Pomacentridae. Lionfish abundances were low (2.6±2.1 ind/120 m2, but in any case Pterois volitans was observed as the eleventh more abundant species, surpassing species of commercial value such as Cephalopholis cruentata. Species that were found in larger numbers (>100, Thalassoma bifasciatum, Haemulon aurolineatum, Canthigaster rostrata, Abudefduf saxatilis, Chromis cyanea, and Stegastes partitus were mainly invertebrate eaters, planctivores, and territorial herbivores. Coral coverage showed higher coral percentages in Chengue (69.9% and Cinto (27.4%, larger sponge percentages in Morro (32.7%; Isla Aguja and Remanso showed the larger figures for abiotic substrate (41.6 and 37%, respectively; corals, sponges, and gorgonians were the components best explaining fish community, but not for the lion fish, which inhabit all studied reef formations. Conclusions. Lion fish is ranked between the 20 more abundant species, with none commercially important species larger, hence no species may qualify as a natural control. Lion fish has as well become a relatively abundant species in Santa Marta reefs, independent of benthic coverage.

Peroxiredoxin 6 from the Antarctic emerald rockcod: molecular characterization of its response to warming.

Science.gov (United States)

Tolomeo, A M; Carraro, A; Bakiu, R; Toppo, S; Place, S P; Ferro, D; Santovito, G

2016-01-01

In the present study, we describe the purification and molecular characterization of two peroxiredoxins (Prdxs), referred to as Prdx6A and Prdx6B, from Trematomus bernacchii, a teleost widely distributed in many areas of Antarctica, that plays a pivotal role in the Antarctic food chain. The two putative amino acid sequences were compared with Prdx6 orthologs from other fish, highlighting a high percentage of identity and similarity with the respective variant, in particular for the residues that are essential for the characteristic peroxidase and phospholipase activities of these enzymes. Phylogenetic analyses suggest the appearance of the two prdx6 genes through a duplication event before the speciation that led to the differentiation of fish families and that the evolution of the two gene variants seems to proceed together with the evolution of fish orders and families. The temporal expression of Prdx6 mRNA in response to short-term thermal stress showed a general upregulation of prdx6b and inhibition of prdx6a, suggesting that the latter is the variant most affected by temperature increase. The variations of mRNA accumulation are more conspicuous in heart than the liver, probably related to behavioral changes of the specimens in response to elevated temperature. These data, together with the peculiar differences between the molecular structures of the two Prdx6s in T. bernacchii as well as in the tropical species Stegastes partitus, suggest an adaptation that allowed these poikilothermic aquatic vertebrates to colonize very different environments, characterized by different temperature ranges.

To fear or to feed: the effects of turbidity on perception of risk by a marine fish.

Science.gov (United States)

Leahy, Susannah M; McCormick, Mark I; Mitchell, Matthew D; Ferrari, Maud C O

2011-12-23

Coral reefs are currently experiencing a number of worsening anthropogenic stressors, with nearshore reefs suffering from increasing sedimentation because of growing human populations and development in coastal regions. In habitats where vision and olfaction serve as the primary sources of information, reduced visual input from suspended sediment may lead to significant alterations in prey fish behaviour. Here, we test whether prey compensate for reduced visual information by increasing their antipredator responses to chemically mediated risk cues in turbid conditions. Experiments with the spiny damselfish, Acanthochromis polyacanthus, found that baseline activity levels were reduced by 23 per cent in high turbidity conditions relative to low turbidity conditions. Furthermore, risk cues elicited strong antipredator responses at all turbidity levels; the strongest antipredator responses were observed in high turbidity conditions, with fish reducing their foraging by almost 40 per cent, as compared with 17 per cent for fish in clear conditions. This provides unambiguous evidence of sensory compensation in a predation context for a tropical marine fish, and suggests that prey fish may be able to behaviourally offset some of the fitness reductions resulting from anthropogenic sedimentation of their habitats.

Molecular signatures of transgenerational response to ocean acidification in a species of reef fish

KAUST Repository

Schunter, Celia Marei; Welch, Megan J.; Ryu, Tae Woo; Zhang, Huoming; Berumen, Michael L.; Nilsson, Gö ran E.; Munday, Philip L.; Ravasi, Timothy

2016-01-01

The impact of ocean acidification on marine ecosystems will depend on species capacity to adapt. Recent studies show that the behaviour of reef fishes is impaired at projected CO levels; however, individual variation exists that might promote adaptation. Here, we show a clear signature of parental sensitivity to high CO in the brain molecular phenotype of juvenile spiny damselfish, Acanthochromis polyacanthus, primarily driven by circadian rhythm genes. Offspring of CO -tolerant and CO -sensitive parents were reared at near-future CO (754 μatm) or present-day control levels (414 μatm). By integrating 33 brain transcriptomes and proteomes with a de novo assembled genome we investigate the molecular responses of the fish brain to increased CO and the expression of parental tolerance to high CO in the offspring molecular phenotype. Exposure to high CO resulted in differential regulation of 173 and 62 genes and 109 and 68 proteins in the tolerant and sensitive groups, respectively. Importantly, the majority of differences between offspring of tolerant and sensitive parents occurred in high CO conditions. This transgenerational molecular signature suggests that individual variation in CO sensitivity could facilitate adaptation of fish populations to ocean acidification.

Ultimate predators: lionfish have evolved to circumvent prey risk assessment abilities.

Science.gov (United States)

Lönnstedt, Oona M; McCormick, Mark I

2013-01-01

Invasive species cause catastrophic alterations to communities worldwide by changing the trophic balance within ecosystems. Ever since their introduction in the mid 1980's common red lionfish, Pterois volitans, are having dramatic impacts on the Caribbean ecosystem by displacing native species and disrupting food webs. Introduced lionfish capture prey at extraordinary rates, altering the composition of benthic communities. Here we demonstrate that the extraordinary success of the introduced lionfish lies in its capacity to circumvent prey risk assessment abilities as it is virtually undetectable by prey species in its native range. While experienced prey damselfish, Chromis viridis, respond with typical antipredator behaviours when exposed to a common predatory rock cod (Cephalopholis microprion) they fail to visibly react to either the scent or visual presentation of the red lionfish, and responded only to the scent (not the visual cue) of a lionfish of a different genus, Dendrochirus zebra. Experienced prey also had much higher survival when exposed to the two non-invasive predators compared to P. volitans. The cryptic nature of the red lionfish has enabled it to be destructive as a predator and a highly successful invasive species.

Lionfish misidentification circumvents an optimized escape response by prey.

Science.gov (United States)

McCormick, Mark I; Allan, Bridie J M

2016-01-01

Invasive lionfish represent an unprecedented problem in the Caribbean basin, where they are causing major changes to foodwebs and habitats through their generalized predation on fishes and invertebrates. To ascertain what makes the red lionfish ( Pterois volitans ) such a formidable predator, we examined the reaction of a native damselfish prey, the whitetail damsel ( Pomacentrus chrysurus ), to a repeatable startle stimulus once they had been forewarned of the sight or smell of lionfish. Fast-start responses were compared with prey forewarned of a predatory rockcod ( Cephalopholis microprion ), a corallivorous butterflyfish ( Chaetodon trifasctiatus ) and experimental controls. Forewarning of the sight, smell or a combination of the two cues from a rockcod led to reduced escape latencies and higher response distances, speed and maximal speed compared with controls, suggesting that forewarning primed the prey and enabled a more effective escape response. In contrast, forewarning of lionfish did not affect the fast-start kinematics measured, which were the same as in the control and non-predatory butterflyfish treatments. Lionfish appear to be able to circumvent mechanisms commonly used by prey to identify predators and were misclassified as non-predatory, and this is likely to contribute to their success as predators.

Ultimate predators: lionfish have evolved to circumvent prey risk assessment abilities.

Directory of Open Access Journals (Sweden)

Oona M Lönnstedt

Full Text Available Invasive species cause catastrophic alterations to communities worldwide by changing the trophic balance within ecosystems. Ever since their introduction in the mid 1980's common red lionfish, Pterois volitans, are having dramatic impacts on the Caribbean ecosystem by displacing native species and disrupting food webs. Introduced lionfish capture prey at extraordinary rates, altering the composition of benthic communities. Here we demonstrate that the extraordinary success of the introduced lionfish lies in its capacity to circumvent prey risk assessment abilities as it is virtually undetectable by prey species in its native range. While experienced prey damselfish, Chromis viridis, respond with typical antipredator behaviours when exposed to a common predatory rock cod (Cephalopholis microprion they fail to visibly react to either the scent or visual presentation of the red lionfish, and responded only to the scent (not the visual cue of a lionfish of a different genus, Dendrochirus zebra. Experienced prey also had much higher survival when exposed to the two non-invasive predators compared to P. volitans. The cryptic nature of the red lionfish has enabled it to be destructive as a predator and a highly successful invasive species.

To fear or to feed: the effects of turbidity on perception of risk by a marine fish

Science.gov (United States)

Leahy, Susannah M.; McCormick, Mark I.; Mitchell, Matthew D.; Ferrari, Maud C. O.

2011-01-01

Coral reefs are currently experiencing a number of worsening anthropogenic stressors, with nearshore reefs suffering from increasing sedimentation because of growing human populations and development in coastal regions. In habitats where vision and olfaction serve as the primary sources of information, reduced visual input from suspended sediment may lead to significant alterations in prey fish behaviour. Here, we test whether prey compensate for reduced visual information by increasing their antipredator responses to chemically mediated risk cues in turbid conditions. Experiments with the spiny damselfish, Acanthochromis polyacanthus, found that baseline activity levels were reduced by 23 per cent in high turbidity conditions relative to low turbidity conditions. Furthermore, risk cues elicited strong antipredator responses at all turbidity levels; the strongest antipredator responses were observed in high turbidity conditions, with fish reducing their foraging by almost 40 per cent, as compared with 17 per cent for fish in clear conditions. This provides unambiguous evidence of sensory compensation in a predation context for a tropical marine fish, and suggests that prey fish may be able to behaviourally offset some of the fitness reductions resulting from anthropogenic sedimentation of their habitats. PMID:21849308

Molecular signatures of transgenerational response to ocean acidification in a species of reef fish

KAUST Repository

Schunter, Celia Marei

2016-07-29

The impact of ocean acidification on marine ecosystems will depend on species capacity to adapt. Recent studies show that the behaviour of reef fishes is impaired at projected CO levels; however, individual variation exists that might promote adaptation. Here, we show a clear signature of parental sensitivity to high CO in the brain molecular phenotype of juvenile spiny damselfish, Acanthochromis polyacanthus, primarily driven by circadian rhythm genes. Offspring of CO -tolerant and CO -sensitive parents were reared at near-future CO (754 μatm) or present-day control levels (414 μatm). By integrating 33 brain transcriptomes and proteomes with a de novo assembled genome we investigate the molecular responses of the fish brain to increased CO and the expression of parental tolerance to high CO in the offspring molecular phenotype. Exposure to high CO resulted in differential regulation of 173 and 62 genes and 109 and 68 proteins in the tolerant and sensitive groups, respectively. Importantly, the majority of differences between offspring of tolerant and sensitive parents occurred in high CO conditions. This transgenerational molecular signature suggests that individual variation in CO sensitivity could facilitate adaptation of fish populations to ocean acidification.

Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach.

Science.gov (United States)

McMahon, Kelton W; Thorrold, Simon R; Houghton, Leah A; Berumen, Michael L

2016-03-01

Coral reefs support spectacularly productive and diverse communities in tropical and sub-tropical waters throughout the world's oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon (C). We coupled compound-specific stable C isotope ratio (δ(13)C) analyses with Bayesian mixing models to quantify C flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ(13)C values of essential amino acids from all baseline C sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single-source end-member often dominated dietary C assimilation of a given species, even for highly mobile, generalist top predators. Microbially reworked detritus was an important secondary C source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, Lutjanus ehrenbergii showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13 % of dietary C) to a phytoplankton-based food web (72 ± 11 %) on oceanic reefs. Our work provides insights into the roles that diverse C sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.

Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach

KAUST Repository

McMahon, Kelton

2015-11-21

Coral reefs support spectacularly productive and diverse communities in tropical and sub-tropical waters throughout the world’s oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon (C). We coupled compound-specific stable C isotope ratio (δ13C) analyses with Bayesian mixing models to quantify C flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ13C values of essential amino acids from all baseline C sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single-source end-member often dominated dietary C assimilation of a given species, even for highly mobile, generalist top predators. Microbially reworked detritus was an important secondary C source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, Lutjanus ehrenbergii showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13 % of dietary C) to a phytoplankton-based food web (72 ± 11 %) on oceanic reefs. Our work provides insights into the roles that diverse C sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.

Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea

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Maha T. Khalil

2017-06-01

Full Text Available Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3–24 km from shore in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals. All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal.

Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea.

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Khalil, Maha T; Bouwmeester, Jessica; Berumen, Michael L

2017-01-01

Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3-24 km from shore) in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals . All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal.

Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea

KAUST Repository

Khalil, Maha T.

2017-06-06

Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3–24 km from shore) in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals. All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal.

Spatial variation in coral reef fish and benthic communities in the central Saudi Arabian Red Sea

KAUST Repository

Khalil, Maha T.; Bouwmeester, Jessica; Berumen, Michael L.

2017-01-01

Local-scale ecological information is critical as a sound basis for spatial management and conservation and as support for ongoing research in relatively unstudied areas. We conducted visual surveys of fish and benthic communities on nine reefs (3–24 km from shore) in the Thuwal area of the central Saudi Arabian Red Sea. Fish biomass increased with increasing distance from shore, but was generally low compared to reefs experiencing minimal human influence around the world. All reefs had a herbivore-dominated trophic structure and few top predators, such as sharks, jacks, or large groupers. Coral cover was considerably lower on inshore reefs, likely due to a 2010 bleaching event. Community analyses showed inshore reefs to be characterized by turf algae, slower-growing corals, lower herbivore diversity, and highly abundant turf-farming damselfishes. Offshore reefs had more planktivorous fishes, a more diverse herbivore assemblage, and faster-growing corals. All reefs appear to be impacted by overfishing, and inshore reefs seem more vulnerable to thermal bleaching. The study provides a description of the spatial variation in biomass and community structure in the central Saudi Arabian Red Sea and provides a basis for spatial prioritization and subsequent marine protected area design in Thuwal.

Spot the difference: mimicry in a coral reef fish.

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Monica Gagliano

Full Text Available Eyespots on the body of many animals have long been assumed to confer protection against predators, but empirical evidence has recently demonstrated that this may not always be the case and suggested that such markings may also serve other purposes. Clearly, this raises the unresolved question of what functions do these markings have and do they contribute to an individual's evolutionary fitness in the wild. Here, we examined the occurrence of eyespots on the dorsal fin of a coral reef damselfish (Pomacentrus amboinensis, where these markings are typical of the juvenile stage and fade away as the fish approaches sexual maturation to then disappear completely in the vast majority of, but not all, adult individuals. By exploring differences in body shape among age and gender groups, we found that individuals retaining the eyespot into adulthood are all sexually mature males, suggesting that these eyespots may be an adult deceptive signal. Interestingly, the body shape of these individuals resembled more closely that of immature females than mature dominant males. These results suggest that eyespots have multiple roles and their functional significance changes within the lifetime of an animal from being a juvenile advertisement to a deceptive adult signal. Male removal experiments or colour manipulations may be necessary to establish specific functions.

Spot the difference: mimicry in a coral reef fish.

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Gagliano, Monica; Depczynski, Martial

2013-01-01

Eyespots on the body of many animals have long been assumed to confer protection against predators, but empirical evidence has recently demonstrated that this may not always be the case and suggested that such markings may also serve other purposes. Clearly, this raises the unresolved question of what functions do these markings have and do they contribute to an individual's evolutionary fitness in the wild. Here, we examined the occurrence of eyespots on the dorsal fin of a coral reef damselfish (Pomacentrus amboinensis), where these markings are typical of the juvenile stage and fade away as the fish approaches sexual maturation to then disappear completely in the vast majority of, but not all, adult individuals. By exploring differences in body shape among age and gender groups, we found that individuals retaining the eyespot into adulthood are all sexually mature males, suggesting that these eyespots may be an adult deceptive signal. Interestingly, the body shape of these individuals resembled more closely that of immature females than mature dominant males. These results suggest that eyespots have multiple roles and their functional significance changes within the lifetime of an animal from being a juvenile advertisement to a deceptive adult signal. Male removal experiments or colour manipulations may be necessary to establish specific functions.

Population assessment of Acropora palmata (Scleractinia: Acroporidae: relationship between habitat and reef associated species

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K. Martínez

2014-09-01

Full Text Available Three decades ago, Acropora palmata was one of the main reef-building coral species throughout the Caribbean, forming an essential component of the structural complexity of shallow coral reef habitats. These colonies still provide microhabitats for settlement, food and shelter to many vertebrates and invertebrates. The recent decline of A. palmata has been followed by a significant loss in spatial heterogeneity and possibly in species diversity. Studies addressing whether dead and living stands of Acropora hold different fish and benthic assemblages are scarce. The status of Acropora colonies and their associated species were assessed in October 2012, at two reef zones of Cayo Sombrero, Venezuela. Visual censuses of fish abundance and the number of macrofaunal individuals were recorded for both live and dead zones. Living Acropora colonies had the lowest abundance (˂31%. In both zoned the fish community was dominated by damselfishes (˂53% and wrasses (˂36%, the benthic macrofauna by peracarid crustaceans (˂40% and polychaetes (˂38%. Fish and benthic communities were not correlated with the condition (live or dead of the Acropora habitats; possibly branching structures provide the necessary shelter and protection no matter if they are dead or alive. More replication is necessary to test this unexpected result.

Identifying carbon sources and trophic position of coral reef fishes using diet and stable isotope (δ15N and δ13C) analyses in two contrasted bays in Moorea, French Polynesia

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Letourneur, Y.; Lison de Loma, T.; Richard, P.; Harmelin-Vivien, M. L.; Cresson, P.; Banaru, D.; Fontaine, M.-F.; Gref, T.; Planes, S.

2013-12-01

Stable isotope ratios (δ15N and δ13C) and diet of three fish species, Stegastes nigricans, Chaetodon citrinellus and Epinephelus merra, were analyzed on the fringing coral reefs of two bays that are differentially exposed to river runoff on Moorea Island, French Polynesia. S. nigricans and C. citrinellus relied mostly on turf algae and presented similar trophic levels and δ15N values, whereas E. merra fed on large invertebrates (crabs and shrimps) and had higher trophic levels and δ15N values. Discrepancies existed between stomach content and stable isotope analyses for the relative importance of food items. Bayesian mixing models indicated that sedimented organic matter was also an important additional food for S. nigricans and C. citrinellus, and fishes for E. merra. The main sources of organic matter involved in the food webs ending with these species were algal turfs and surface sediments, while water particulate organic matter was barely used. Significant spatial differences in C and N isotopic ratios for sources and fishes were found within and between bays. Lower 13C and higher 15N values were observed for various compartments of the studied trophic network at the end of each bay than at the entrance. Differences were observed between bays, with organic sources and consumers being, on average, slightly more 13C-depleted and 15N-enriched in Cook's Bay than in Opunohu Bay, linked with a higher mean annual flow of the river at Cook's Bay. Our results suggest that rivers bring continental material into these two bays, which is partly incorporated into the food webs of fringing coral reefs at least close to river mouths. Thus, continental inputs can influence the transfer of organic matter within coral reef food webs depending on the diet of organisms.

Immigration Rates during Population Density Reduction in a Coral Reef Fish

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Turgeon, Katrine; Kramer, Donald L.

2016-01-01

Although the importance of density-dependent dispersal has been recognized in theory, few empirical studies have examined how immigration changes over a wide range of densities. In a replicated experiment using a novel approach allowing within-site comparison, we examined changes in immigration rate following the gradual removal of territorial damselfish from a limited area within a much larger patch of continuous habitat. In all sites, immigration occurred at intermediate densities but did not occur before the start of removals and only rarely as density approached zero. In the combined data and in 5 of 7 sites, the number of immigrants was a hump-shaped function of density. This is the first experimental evidence for hump-shaped, density-dependent immigration. This pattern may be more widespread than previously recognized because studies over more limited density ranges have identified positive density dependence at low densities and negative density dependence at high densities. Positive density dependence at low density can arise from limits to the number of potential immigrants and from behavioral preferences for settling near conspecifics. Negative density dependence at high density can arise from competition for resources, especially high quality territories. The potential for non-linear effects of local density on immigration needs to be recognized for robust predictions of conservation reserve function, harvest impacts, pest control, and the dynamics of fragmented populations. PMID:27271081

The ART of mating: alternative reproductive tactics and mating success in a nest-guarding fish.

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Mascolino, S; Benvenuto, C; Gubili, C; Sacchi, C; Boufana, B; Mariani, S

2016-12-01

Behavioural observations in the field of male Mediterranean damselfish Chromis chromis were combined with molecular analyses, using bi-parentally and maternally inherited markers, to investigate reproductive success patterns of alternative reproductive tactics (ARTs) in terms of number of eggs sired and number of females contributing to each nest. Cuckoldry was observed in every nest sampled, with at least two and up to seven sneaker males per nest. The nesting male, however, always significantly fertilized the greater number of eggs (on average 49%) in each clutch, whereas each sneaker fertilized around 7% of the clutch. The average number of females whose eggs were fertilized by nesting males was 6·76 (range 2-13), while each sneaker on average fertilized the eggs of 1·74 (range 1-8) females. Using this sibship reconstruction, some of the factors involved in the regulation of the dynamic equilibrium of reproductive success were investigated between the two ARTs shown by C. chromis males. Results show that the sneakers' reproductive success was positively linked to egg clutch size; the density of individuals in the nesting area negatively affected the size of egg clutches; the rate of defence behaviours performed by nesting males negatively influenced the number of females contributing to each nest. © 2016 The Fisheries Society of the British Isles.

Climate-driven coral reorganisation influences aggressive behaviour in juvenile coral-reef fishes

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Kok, Judith E.; Graham, Nicholas A. J.; Hoogenboom, Mia O.

2016-06-01

Globally, habitat degradation is altering the abundance and diversity of species in a variety of ecosystems. This study aimed to determine how habitat degradation, in terms of changing coral composition under climate change, affected abundance, species richness and aggressive behaviour of juveniles of three damselfishes ( Pomacentrus moluccensis, P. amboinensis and Dischistodus perspicillatus, in order of decreasing reliance on coral). Patch reefs were constructed to simulate two types of reefs: present-day reefs that are vulnerable to climate-induced coral bleaching, and reefs with more bleaching-robust coral taxa, thereby simulating the likely future of coral reefs under a warming climate. Fish communities were allowed to establish naturally on the reefs during the summer recruitment period. Climate-robust reefs had lower total species richness of coral-reef fishes than climate-vulnerable reefs, but total fish abundance was not significantly different between reef types (pooled across all species and life-history stages). The nature of aggressive interactions, measured as the number of aggressive chases, varied according to coral composition; on climate-robust reefs, juveniles used the substratum less often to avoid aggression from competitors, and interspecific aggression became relatively more frequent than intraspecific aggression for juveniles of the coral-obligate P. moluccensis. This study highlights the importance of coral composition as a determinant of behaviour and diversity of coral-reef fishes.

Impact of motorboats on fish embryos depends on engine type.

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Jain-Schlaepfer, Sofia; Fakan, Eric; Rummer, Jodie L; Simpson, Stephen D; McCormick, Mark I

2018-01-01

Human generated noise is changing the natural underwater soundscapes worldwide. The most pervasive sources of underwater anthropogenic noise are motorboats, which have been found to negatively affect several aspects of fish biology. However, few studies have examined the effects of noise on early life stages, especially the embryonic stage, despite embryo health being critical to larval survival and recruitment. Here, we used a novel setup to monitor heart rates of embryos from the staghorn damselfish ( Amblyglyphidodon curacao ) in shallow reef conditions, allowing us to examine the effects of in situ boat noise in context with real-world exposure. We found that the heart rate of embryos increased in the presence of boat noise, which can be associated with the stress response. Additionally, we found 2-stroke outboard-powered boats had more than twice the effect on embryo heart rates than did 4-stroke powered boats, showing an increase in mean individual heart rate of 1.9% and 4.6%, respectively. To our knowledge this is the first evidence suggesting boat noise elicits a stress response in fish embryo and highlights the need to explore the ecological ramifications of boat noise stress during the embryo stage. Also, knowing the response of marine organisms caused by the sound emissions of particular engine types provides an important tool for reef managers to mitigate noise pollution.

Expression and localization of forkhead transcriptional factor 2 (Foxl2 in the gonads of protogynous wrasse, Halichoeres trimaculatus

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Kobayashi Yasuhisa

2010-11-01

Full Text Available Abstract Background Three-spot wrasse, Halichoeres trimaculatus, is a marine protogynous hermaphrodite fish. Individuals mature either as initial phase (IP males or females. Appropriate social cues induce the sex change from IP female to terminal phase (TP male. However, the molecular mechanisms behind such a sex change remain largely unknown. Recently, the forkhead transcription factor 2 (Foxl2 was identified as an essential regulator of vertebrate ovarian development/function/phenotype. Inspired by this information, we characterized the expression patterns of Foxl2 in the protogynous wrasse assuming Foxl2 as the female-specific marker in this species. Methods First, we clonedFoxl2 cDNA from ovary by reverse transcription polymerase chain reaction (RT-PCR followed by rapid amplification of cDNA ends (RACE. Next, we analysed expression pattern of Foxl2 messenger RNA (mRNA and protein in gonads of different sexual phases by real time quantitative PCR assay and flour fluorescence immunohistochemical method, respectively. Additionally, we studied the changes in Foxl2 expression pattern during aromatase inhibitor (AI-induced sex change. Results The amino acid sequence (306 AA of wrasse Foxl2, especially the forkhead domain, shows high identity with that of other reported teleost Foxl2s. Quite unexpectedly, no sexual dimorphism was observable between the testes and ovary in the expression pattern of Foxl2. In female phase fish, signals for Foxl2 protein were detectable in the granulosa cells, but not the theca cells. Transcript levels of Foxl2 in the testes of IP and TP males were identical to that in the ovaries of females and, further, Foxl2 protein was found to be localized in the interstitial cells including tubules and Leydig cells. Treatment with AI induced sex change in male gonads and an up-regulation was seen in the expression of Foxl2 in these gonads. Conclusions Unlike in other vertebrates, including teleosts, Foxl2 may have a different

Behaviourally mediated phenotypic selection in a disturbed coral reef environment.

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Mark I McCormick

2009-09-01

Full Text Available Natural and anthropogenic disturbances are leading to changes in the nature of many habitats globally, and the magnitude and frequency of these perturbations are predicted to increase under climate change. Globally coral reefs are one of the most vulnerable ecosystems to climate change. Fishes often show relatively rapid declines in abundance when corals become stressed and die, but the processes responsible are largely unknown. This study explored the mechanism by which coral bleaching may influence the levels and selective nature of mortality on a juvenile damselfish, Pomacentrus amboinensis, which associates with hard coral. Recently settled fish had a low propensity to migrate small distances (40 cm between habitat patches, even when densities were elevated to their natural maximum. Intraspecific interactions and space use differ among three habitats: live hard coral, bleached coral and dead algal-covered coral. Large fish pushed smaller fish further from the shelter of bleached and dead coral thereby exposing smaller fish to higher mortality than experienced on healthy coral. Small recruits suffered higher mortality than large recruits on bleached and dead coral. Mortality was not size selective on live coral. Survival was 3 times as high on live coral as on either bleached or dead coral. Subtle behavioural interactions between fish and their habitats influence the fundamental link between life history stages, the distribution of phenotypic traits in the local population and potentially the evolution of life history strategies.

Unusual “Knob-Like Chimney” Growth Forms on Acropora Species in the Caribbean

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Andrea Rivera-Sosa

2018-02-01

Full Text Available This manuscript provides new insights on an unusual morphological plasticity growth form on Acropora spp. in the Caribbean. This abnormal knob-shaped growth is thought to be a progression from the damselfish “chimneys” that are commonly seen in coral-algal farms. However, the diameters of the observed knobs tend to be much larger on Acropora palmata, where they range from 1.37 to 5.44 cm in diameter, and they tend to be slightly smaller on A. prolifera, where they range from 1.1 to 2.72 cm in diameter. These knob-like chimney growths can affect entire colonies. The knobs are mostly covered with live tissue, while some knobs compete with turf algae. We hypothesize that these growths may be linked to stress from multiple predation and environmental conditions. Local stressors could synergistically influence the regeneration of scarred tissue and skeleton that result from predatory lesions, possibly leading to the formation of the knobs. Therefore, we provide preliminary data from a shallow reef site in coastal Honduras located within the Mesoamerican region where we found the knobs. To the best of our knowledge, the conditions that drive the occurrence of these unusual “knob-like chimneys” on Acropora spp. have not been previously assessed. Thus, we propose a series of guidelines to research the coral morphological plasticity that may be linked to this knob-like chimney phenomenon.

Potential of Pigeon Creek, San Salvador, Bahamas, as Nursery Habitat for Juvenile Reef Fish

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Conboy, Ian Christopher

2011-10-01

Full Text Available This project assessed the significance of Pigeon Creek, San Salvador, Bahamas as a nursery habitat for coral reef fishes. Pigeon Creek’s perimeter is lined with mangrove and limestone bedrock. The bottom is sand or seagrass and ranges in depth from exposed at low tide to a 3-m deep, tide-scoured channel. In June 2006 and January 2007, fish were counted and their maturity was recorded while sampling 112 of 309 possible 50-m transects along the perimeter of the Pigeon Creek. Excluding silversides (Atherinidae, 52% of fish counted, six families each comprised >1% of the total abundance (Scaridae/parrotfishes, 35.3%; Lutjanidae/snappers, 23.9%; Haemulidae/grunts, 21.0%; Gerreidae/mojarras, 8.5%; Pomacentridae/damselfishes, 6.1%; Labridae/wrasses, 2.4%. There were few differences in effort-adjusted counts among habitats (mangrove, bedrock, mixed, sections (north, middle, southwest and seasons (summer 2006 and winter 2007. Red Mangrove (Rhizophora mangle, covering 68% of the perimeter was where 62% of the fish were counted. Snappers, grunts and parrotfishes are important food fishes and significant families in terms of reef ecology around San Salvador. Mangrove was the most important habitat for snappers and grunts; bedrock was most important for parrotfishes. The southwest section was important for snappers, grunts and parrotfishes, the north section for grunts and parrotfishes, and the middle section for snappers. Among the non-silverside fish counted, 91.2% were juveniles. These results suggest that Pigeon Creek is an important nursery for the coral reefs surrounding San Salvador and should be protected from potential disturbances.

The importance of sponges and mangroves in supporting fish communities on degraded coral reefs in Caribbean Panama.

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Seemann, Janina; Yingst, Alexandra; Stuart-Smith, Rick D; Edgar, Graham J; Altieri, Andrew H

2018-01-01

Fish communities associated with coral reefs worldwide are threatened by habitat degradation and overexploitation. We assessed coral reefs, mangrove fringes, and seagrass meadows on the Caribbean coast of Panama to explore the influences of their proximity to one another, habitat cover, and environmental characteristics in sustaining biomass, species richness and trophic structure of fish communities in a degraded tropical ecosystem. We found 94% of all fish across all habitat types were of small body size (≤10 cm), with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes) and Gobiidae (gobies). Total fish biomass was very low, with the trend of small fishes from low trophic levels over-represented, and top predators under-represented, relative to coral reefs elsewhere in the Caribbean. For example, herbivorous fishes comprised 27% of total fish biomass in Panama relative to 10% in the wider Caribbean, and the small parrotfish Scarus iseri comprised 72% of the parrotfish biomass. We found evidence that non-coral biogenic habitats support reef-associated fish communities. In particular, the abundance of sponges on a given reef and proximity of mangroves were found to be important positive correlates of reef fish species richness, biomass, abundance and trophic structure. Our study indicates that a diverse fish community can persist on degraded coral reefs, and that the availability and arrangement within the seascape of other habitat-forming organisms, including sponges and mangroves, is critical to the maintenance of functional processes in such ecosystems.

The importance of sponges and mangroves in supporting fish communities on degraded coral reefs in Caribbean Panama

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Janina Seemann

2018-03-01

Full Text Available Fish communities associated with coral reefs worldwide are threatened by habitat degradation and overexploitation. We assessed coral reefs, mangrove fringes, and seagrass meadows on the Caribbean coast of Panama to explore the influences of their proximity to one another, habitat cover, and environmental characteristics in sustaining biomass, species richness and trophic structure of fish communities in a degraded tropical ecosystem. We found 94% of all fish across all habitat types were of small body size (≤10 cm, with communities dominated by fishes that usually live in habitats of low complexity, such as Pomacentridae (damselfishes and Gobiidae (gobies. Total fish biomass was very low, with the trend of small fishes from low trophic levels over-represented, and top predators under-represented, relative to coral reefs elsewhere in the Caribbean. For example, herbivorous fishes comprised 27% of total fish biomass in Panama relative to 10% in the wider Caribbean, and the small parrotfish Scarus iseri comprised 72% of the parrotfish biomass. We found evidence that non-coral biogenic habitats support reef-associated fish communities. In particular, the abundance of sponges on a given reef and proximity of mangroves were found to be important positive correlates of reef fish species richness, biomass, abundance and trophic structure. Our study indicates that a diverse fish community can persist on degraded coral reefs, and that the availability and arrangement within the seascape of other habitat-forming organisms, including sponges and mangroves, is critical to the maintenance of functional processes in such ecosystems.

Reef odor: a wake up call for navigation in reef fish larvae.

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Claire B Paris

Full Text Available The behavior of reef fish larvae, equipped with a complex toolbox of sensory apparatus, has become a central issue in understanding their transport in the ocean. In this study pelagic reef fish larvae were monitored using an unmanned open-ocean tracking device, the drifting in-situ chamber (DISC, deployed sequentially in oceanic waters and in reef-born odor plumes propagating offshore with the ebb flow. A total of 83 larvae of two taxonomic groups of the families Pomacentridae and Apogonidae were observed in the two water masses around One Tree Island, southern Great Barrier Reef. The study provides the first in-situ evidence that pelagic reef fish larvae discriminate reef odor and respond by changing their swimming speed and direction. It concludes that reef fish larvae smell the presence of coral reefs from several kilometers offshore and this odor is a primary component of their navigational system and activates other directional sensory cues. The two families expressed differences in their response that could be adapted to maintain a position close to the reef. In particular, damselfish larvae embedded in the odor plume detected the location of the reef crest and swam westward and parallel to shore on both sides of the island. This study underlines the critical importance of in situ Lagrangian observations to provide unique information on larval fish behavioral decisions. From an ecological perspective the central role of olfactory signals in marine population connectivity raises concerns about the effects of pollution and acidification of oceans, which can alter chemical cues and olfactory responses.

Influence of habitat degradation on fish replenishment

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McCormick, M. I.; Moore, J. A. Y.; Munday, P. L.

2010-09-01

Temperature-induced coral bleaching is a major threat to the biodiversity of coral reef ecosystems. While reductions in species diversity and abundance of fish communities have been documented following coral bleaching, the mechanisms that underlie these changes are poorly understood. The present study examined the impacts of coral bleaching on the early life-history processes of coral reef fishes. Daily monitoring of fish settlement patterns found that ten times as many fish settled to healthy coral than sub-lethally bleached coral. Species diversity of settling fishes was least on bleached coral and greatest on dead coral, with healthy coral having intermediate levels of diversity. Laboratory experiments using light-trap caught juveniles showed that different damselfish species chose among healthy, bleached and dead coral habitats using different combinations of visual and olfactory cues. The live coral specialist, Pomacentrus moluccensis, preferred live coral and avoided bleached and dead coral, using mostly visual cues to inform their habitat choice. The habitat generalist, Pomacentrus amboinensis, also preferred live coral and avoided bleached and dead coral but selected these habitats using both visual and olfactory cues. Trials with another habitat generalist, Dischistodus sp., suggested that vision played a significant role. A 20 days field experiment that manipulated densities of P. moluccensis on healthy and bleached coral heads found an influence of fish density on juvenile weight and growth, but no significant influence of habitat quality. These results suggests that coral bleaching will affect settlement patterns and species distributions by influencing the visual and olfactory cues that reef fish larvae use to make settlement choices. Furthermore, increased fish density within the remaining healthy coral habitats could play an important role in influencing population dynamics.

A comparison of measures of boldness and their relationships to survival in young fish.

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James R White

Full Text Available Boldness is the propensity of an animal to engage in risky behavior. Many variations of novel-object or novel-environment tests have been used to quantify the boldness of animals, although the relationship between test outcomes has rarely been investigated. Furthermore, the relationship of outcomes to any ecological aspect of fitness is generally assumed, rather than measured directly. Our study is the first to compare how the outcomes of the same test of boldness differ among observers and how different tests of boldness relate to the survival of individuals in the field. Newly-metamorphosed lemon damselfish, Pomacentrus moluccensis, were placed onto replicate patches of natural habitat. Individual behavior was quantified using four tests (composed of a total of 12 different measures of behavior: latency to enter a novel environment, activity in a novel environment, and reactions to threatening and benign novel objects. After behavior was quantified, survival was monitored for two days during which time fish were exposed to natural predators. Variation among observers was low for most of the 12 measures, except distance moved and the threat test (reaction to probe thrust, which displayed unacceptable amounts of inter-observer variation. Overall, the results of the behavioral tests suggested that novel environment and novel object tests quantified similar behaviors, yet these behavioral measures were not interchangeable. Multiple measures of behavior within the context of novel environment or object tests were the most robust way to assess boldness and these measures have a complex relationship with survivorship of young fish in the field. Body size and distance ventured from shelter were the only variables that had a direct and positive relationship with survival.

Contrasting Evolutionary Paths Among Indo-Pacific Pomacentrus Species Promoted by Extensive Pericentric Inversions and Genome Organization of Repetitive Sequences.

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Getlekha, Nuntaporn; Cioffi, Marcelo de Bello; Maneechot, Nuntiya; Bertollo, Luiz Antônio Carlos; Supiwong, Weerayuth; Tanomtong, Alongklod; Molina, Wagner Franco

2018-02-01

Pomacentrus (damselfishes) is one of the most characteristic groups of fishes in the Indo-Pacific coral reef. Its 77 described species exhibit a complex taxonomy with cryptic lineages across their extensive distribution. Periods of evolutionary divergences between them are very variable, and the cytogenetic events that followed their evolutionary diversification are largely unknown. In this respect, analyses of chromosomal divergence, within a phylogenetic perspective, are particularly informative regarding karyoevolutionary trends. As such, we conducted conventional cytogenetic and cytogenomic analyses in four Pomacentrus species (Pomacentrus similis, Pomacentrus auriventris, Pomacentrus moluccensis, and Pomacentrus cuneatus), through the mapping of repetitive DNA classes and transposable elements, including 18S rDNA, 5S rDNA, (CA) 15 , (GA) 15 , (CAA) 10 , Rex6, and U2 snDNA as markers. P. auriventris and P. similis, belonging to the Pomacentrus coelestis complex, have indistinguishable karyotypes (2n = 48; NF = 48), with a peculiar syntenic organization of ribosomal genes. On the other hand, P. moluccensis and P. cuneatus, belonging to another clade, exhibit very different karyotypes (2n = 48, NF = 86 and 92, respectively), with a large number of bi-armed chromosomes, where multiple pericentric inversions played a significant role in their karyotype organization. In this sense, different chromosomal pathways followed the phyletic diversification in the Pomacentrus genus, making possible the characterization of two well-contrasting species groups regarding their karyotype features. Despite this, pericentric inversions act as an effective postzygotic barrier in many organisms, which appear to be also the case for P. moluccensis and P. cuneatus; the extensive chromosomal similarities in the two species of P. coelestis complex suggest minor participation of chromosomal postzygotic barriers in the phyletic diversification of these species.

Possible recovery of Acropora palmata (Scleractinia:Acroporidae within the Veracruz Reef System, Gulf of Mexico: a survey of 24 reefs to assess the benthic communities

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Elizabeth A. Larson

2014-09-01

Full Text Available Recent evidence shows that Acropora palmata within the Veracruz Reef System, located in the southwestern Gulf of Mexico, may be recovering after the die off from the flooding of the Jamapa River and a dramatic cold water event in the 1970s. Since this decline, few surveys have documented the status of A. palmata. The 28 named reefs in the system are divided into 13 northern and 15 southern groups by the River. Between 2007 and 2013, we surveyed 24 reefs to assess the benthic communities. Seven of the 11 reefs surveyed in the northern group and all in the southern group had A. palmata. Colonies were typically found on the windward side of the reefs in shallow waters along the reef edges or crest. We also recorded colony diameter and condition along belt transects at two reefs in the north (Anegada de Adentro and Verde and two in the south (Periferico and Sargazo, between 2011 and 2013. In addition, eight permanent transects were surveyed at Rizo (south. A total of 1 804 colonies were assessed; densities ranged from 0.02 to 0.28 colonies/m² (mean (±SD, colony diameter of 58 ± 73cm, and 89 ± 18% live tissue per colony. Total prevalence of predation by damselfish was 5%, by snails 2%, and <1% by fireworms, disease prevalence was <3%. Size frequency distributions indicated that all of the sites had a moderate to high spawning potential, 15-68% of the colonies at each site were mature, measuring over 1 600cm². The presence of these healthy and potentially reproductive colonies is important for species recovery, particularly because much of the greater Caribbean still shows little to no signs of recovery. Conservation and management efforts of these reefs are vital.

Post-Disturbance Stability of Fish Assemblages Measured at Coarse Taxonomic Resolution Masks Change at Finer Scales.

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Ceccarelli, Daniela M; Emslie, Michael J; Richards, Zoe T

2016-01-01

Quantifying changes to coral reef fish assemblages in the wake of cyclonic disturbances is challenging due to spatial variability of damage inherent in such events. Often, fish abundance appears stable at one spatial scale (e.g. reef-wide), but exhibits substantial change at finer scales (e.g. site-specific decline or increase). Taxonomic resolution also plays a role; overall stability at coarse taxonomic levels (e.g. family) may mask species-level turnover. Here we document changes to reef fish communities after severe Tropical Cyclone Ita crossed Lizard Island, Great Barrier Reef. Coral and reef fish surveys were conducted concurrently before and after the cyclone at four levels of exposure to the prevailing weather. Coral cover declined across all exposures except sheltered sites, with the largest decline at exposed sites. There was no significant overall reduction in the total density, biomass and species richness of reef fishes between 2011 and 2015, but individual fish taxa (families and species) changed in complex and unpredictable ways. For example, more families increased in density and biomass than decreased following Cyclone Ita, particularly at exposed sites whilst more fish families declined at lagoon sites even though coral cover did not decline. All sites lost biomass of several damselfish species, and at most sites there was an increase in macroinvertivores and grazers. Overall, these results suggest that the degree of change measured at coarse taxonomic levels masked high species-level turnover, although other potential explanations include that there was no impact of the storm, fish assemblages were impacted but underwent rapid recovery or that there is a time lag before the full impacts become apparent. This study confirms that in high-complexity, high diversity ecosystems such as coral reefs, species level analyses are essential to adequately capture the consequences of disturbance events.

Effects of isolation and fishing on the marine ecosystems of Easter Island and Salas y Gómez, Chile

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Friedlander, Alan M.; Ballesteros, Enric; Beets, Jim; Berkenpas, Eric; Gaymer, Carlos F.; Gorny, Matthias; Sala, Enric

2013-01-01

1. An expedition to Salas y Gómez and Easter islands was conducted to develop a comprehensive baseline of the nearshore marine ecosystem, to survey seamounts of the recently created Motu Motiro Hiva Marine Park (MMHMP) – a no-take marine reserve of 150 000 km2 – and to compare these results with Easter Island where the marine ecosystem is similar but has no marine protection. 2. Live coral cover was surprisingly high at both Easter Island (53%) and Salas y Gómez (44%), especially considering their sub-tropical location, high wave energy environments, and geographic isolation. 3. Endemic and regionally-endemic species comprised 77% of the fish abundance at Easter Island and 73% at Salas y Gómez. Fish biomass at Salas y Gómez was relatively high (1.2 t ha-1) and included a large proportion of apex predators (43%), whereas at Easter Island it was almost three times lower (0.45 t ha-1) with large predators accounting for less than 2% of the biomass, despite good habitat quality. 4. The large cohort of small sharks and the absence of larger sharks at Salas y Gómez suggest mesopredator release consistent with recent shark fishing. The fish fauna at the seamounts between Easter Island and Salas y Gómez, outside of MMHMP, harboured 46% endemic species, including a new species of damselfish (Chromis sp. nov.) and probably a new species of Chimaera (Hydrolagus). Numerous seamounts adjacent to Salas y Gómez are currently not included in the MMHMP. 5. This expedition highlights the high biodiversity value of this remote part of the Pacific owing to the uniqueness (endemicity) of the fauna, large apex predator biomass, and geographic isolation.

High prevalence of homing behaviour among juvenile coral-reef fishes and the role of body size

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Streit, Robert P.; Bellwood, David R.

2017-12-01

Adult coral-reef fishes display a remarkable ability to return home after being displaced. However, we know very little about homing behaviour in juvenile fishes. Homing behaviour in juvenile fishes is of interest because it will shape subsequent spatial distributions of adult fish communities. Comparing multiple species, families and functional groups allows us to distinguish between species-specific traits and more generalised, species-independent traits that may drive homing behaviour. Using displacement experiments of up to 150 m, we quantified homing behaviour of juvenile, newly recruited reef fishes of seven species in three families, including herbivorous parrotfishes and rabbitfishes, carnivorous wrasse and planktivorous damselfishes. All species showed the ability to home successfully, but success rates differed among species. Juvenile parrotfishes were the most successful (67% returning home), while return rates in the other species ranged from 10.5% ( Siganus doliatus) to 28.9% ( Coris batuensis). However, across all species body size appeared to be the main driver of homing success, rather than species-specific traits. With every cm increase in body size, odds of returning home almost tripled (170% increase) across all species. Interestingly, the probability of getting lost was not related to body size, which suggests that mortality was not a major driver of unsuccessful homing. Homing probability halved beyond displacement distances of 10 m and then remained stable. Higher likelihood of homing over short distances may suggest that different sensory cues are used to navigate. Overall, our results suggest that homing ability is a widespread trait among juvenile reef fishes. A `sense of home' and site attachment appear to develop early during ontogeny, especially above taxon-specific size thresholds. Hence, spatial flexibility exists only in a brief window after settlement, with direct implications for subsequent patterns of connectivity and ecosystem

Potential for adaptation to climate change in a coral reef fish.

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Munday, Philip L; Donelson, Jennifer M; Domingos, Jose A

2017-01-01

Predicting the impacts of climate change requires knowledge of the potential to adapt to rising temperatures, which is unknown for most species. Adaptive potential may be especially important in tropical species that have narrow thermal ranges and live close to their thermal optimum. We used the animal model to estimate heritability, genotype by environment interactions and nongenetic maternal components of phenotypic variation in fitness-related traits in the coral reef damselfish, Acanthochromis polyacanthus. Offspring of wild-caught breeding pairs were reared for two generations at current-day and two elevated temperature treatments (+1.5 and +3.0 °C) consistent with climate change projections. Length, weight, body condition and metabolic traits (resting and maximum metabolic rate and net aerobic scope) were measured at four stages of juvenile development. Additive genetic variation was low for length and weight at 0 and 15 days posthatching (dph), but increased significantly at 30 dph. By contrast, nongenetic maternal effects on length, weight and body condition were high at 0 and 15 dph and became weaker at 30 dph. Metabolic traits, including net aerobic scope, exhibited high heritability at 90 dph. Furthermore, significant genotype x environment interactions indicated potential for adaptation of maximum metabolic rate and net aerobic scope at higher temperatures. Net aerobic scope was negatively correlated with weight, indicating that any adaptation of metabolic traits at higher temperatures could be accompanied by a reduction in body size. Finally, estimated breeding values for metabolic traits in F2 offspring were significantly affected by the parental rearing environment. Breeding values at higher temperatures were highest for transgenerationally acclimated fish, suggesting a possible role for epigenetic mechanisms in adaptive responses of metabolic traits. These results indicate a high potential for adaptation of aerobic scope to higher temperatures

Sediment-induced turbidity impairs foraging performance and prey choice of planktivorous coral reef fishes.

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Johansen, J L; Jones, G P

2013-09-01

Sedimentation is a substantial threat to aquatic ecosystems and a primary cause of habitat degradation on near-shore coral reefs. Although numerous studies have demonstrated major impacts of sedimentation and turbidity on corals, virtually nothing is known of the sensitivity of reef fishes. Planktivorous fishes are an important trophic group that funnels pelagic energy sources into reef ecosystems. These fishes are visual predators whose foraging is likely to be impaired by turbidity, but the threshold for such effects and their magnitude are unknown. This study examined the effect of sediment-induced turbidity on foraging in four species of planktivorous damselfishes (Pomacentridae) of the Great Barrier Reef, including inshore and offshore species that potentially differ in tolerance for turbidity. An experimental flow tunnel was used to quantify their ability to catch mobile and immobile planktonic prey under different levels of turbidity and velocity in the range encountered on natural and disturbed reefs. Turbidity of just 4 NTU (nephelometric turbidity units) reduced average attack success by up to 56%, with higher effect sizes for species with offshore distributions. Only the inshore species (Neopomacentrus bankieri), which frequently encounters this turbidity on coastal reefs, could maintain high prey capture success. At elevated turbidity similar to that found on disturbed reefs (8 NTU), attack success was reduced in all species examined by up to 69%. These reductions in attack success led to a 21-24% decrease in foraging rates for all mid to outer-shelf species, in spite of increasing attack rates at high turbidity. Although effects of turbidity varied among species, it always depended heavily on prey mobility and ambient velocity. Attack success was up to 14 times lower on mobile prey, leaving species relatively incapable of foraging on anything but immobile prey at high turbidity. Effects of turbidity were particularly prominent at higher velocities, as

Beyond the transect: An alternative microchemical imaging method for fine scale analysis of trace elements in fish otoliths during early life

International Nuclear Information System (INIS)

McGowan, Nicole; Fowler, Ashley M.; Parkinson, Kerryn; Bishop, David P.; Ganio, Katherine; Doble, Philip A.; Booth, David J.; Hare, Dominic J.

2014-01-01

Microchemical analysis of otolith (calcified ‘ear stones’ used for balance and orientation) of fishes is an important tool for studying their environmental history and management. However, the spatial resolution achieved is often too coarse to examine short-term events occurring in early life. Current methods rely on single points or transects across the otolith surface, which may provide a limited view of elemental distributions, a matter that has not previously been investigated. Imaging by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) permits microchemical analyses of short-term events in early life with high (< 10 μm) resolution, two-dimensional (2D) visualization of elemental distributions. To demonstrate the potential of this method, we mapped the concentrations of Sr and Ba, two key trace elements, in a small number of juvenile otoliths of neon damselfish (Pomacentrus coelestis) using an 8 μm beam diameter (laser fluence of 13.8 ± 3.5 J cm −2 ). Quantification was performed using the established method by Longerich et al. (1996), which is applied to 2D imaging of a biological matrix here for the first time. Accuracy of > 97% was achieved using a multi-point non matrix-matched calibration of National Institute of Standards and Technology (NIST) 610 and 612 (trace elements in glass) using Longerich's calculation method against the matrix-matched standard FEBS-1 (powdered red snapper [Lutjanus campechanus] otolith). The spatial resolution achieved in the otolith corresponded to a time period of 2 ± 1 days during the larval phase, and 4 ± 1 days during the post-settlement juvenile phase. This method has the potential to improve interpretations of early life-history events at scales corresponding to specific events. While the images showed gradients in Sr and Ba across the larval settlement zone more clearly than single transects, the method proved sample homogeneity throughout the structure; demonstrating that 2D

The Assessment of Current Biogeographic Patterns of Coral Reef Fishes in the Red Sea by Incorporating Their Evolutionary and Ecological Background

KAUST Repository

Robitzch Sierra, Vanessa S. N.

2017-03-01

The exceptional environment of the Red Sea has lead to high rates of endemism and biodiversity. Located at the periphery of the world’s coral reefs distribution, its relatively young reefs offer an ideal opportunity to study biogeography and underlying evolutionary and ecological triggers. Here, I provide baseline information on putative seasonal recruitment patterns of reef fishes along a cross shelf gradient at an inshore, mid-shelf, and shelf-edge reef in the central Saudi Arabian Red Sea. I propose a basic comparative model to resolve biogeographic patterns in endemic and cosmopolitan reef fishes. Therefore, I chose the genetically, biologically, and ecologically similar coral-dwelling damselfishes Dascyllus aruanus and D. marginatus as a model species-group. As a first step, basic information on the distribution, population structure, and genetic diversity is evaluated within and outside the Red Sea along most of their global distribution. Second, pelagic larval durations (PLDs) within the Red Sea environmental gradient are explored. For the aforementioned, PLDs of the only other Red Sea Dascyllus, D. trimaculatus, are included for a more comprehensive comparison. Third, to further assess ongoing pathways of connectivity and geneflow related to larval behavior and dispersal in Red Sea reef fishes, the genetic composition and kinship of a single recruitment cohort of D. aruanus arriving together at one single reef is quantified using single nuclear polymorphisms (SNPs). Genetic diversity and relatedness of the recruits are compared to that of the standing population at the settlement reef, providing insight into putative dispersal strategies and behavior of coral reef fish larvae. As a fourth component to study traits shaping biogeography, the ecology and adaptive potential of the cosmopolitan D. aruanus is described by studying morphometric-geometrics of the body structure in relation to the stomach content and prey type from specimen along the cross

Beyond the transect: An alternative microchemical imaging method for fine scale analysis of trace elements in fish otoliths during early life

Energy Technology Data Exchange (ETDEWEB)

McGowan, Nicole [Elemental Bio-imaging Facility, University of Technology, Sydney, New South Wales (Australia); CCFS ARC Centre of Excellence, Department of Earth and Planetary Sciences, Macquarie University, Sydney (Australia); Fowler, Ashley M.; Parkinson, Kerryn [Fish Ecology Laboratory, School of the Environment, University of Technology, Sydney, New South Wales (Australia); Bishop, David P. [Elemental Bio-imaging Facility, University of Technology, Sydney, New South Wales (Australia); Ganio, Katherine [Florey Department of Neuroscience and Mental Health, University of Melbourne, Victoria (Australia); Doble, Philip A. [Elemental Bio-imaging Facility, University of Technology, Sydney, New South Wales (Australia); Booth, David J. [Fish Ecology Laboratory, School of the Environment, University of Technology, Sydney, New South Wales (Australia); Hare, Dominic J., E-mail: dominic.hare@uts.edu.au [Elemental Bio-imaging Facility, University of Technology, Sydney, New South Wales (Australia); Florey Department of Neuroscience and Mental Health, University of Melbourne, Victoria (Australia)

2014-10-01

Microchemical analysis of otolith (calcified ‘ear stones’ used for balance and orientation) of fishes is an important tool for studying their environmental history and management. However, the spatial resolution achieved is often too coarse to examine short-term events occurring in early life. Current methods rely on single points or transects across the otolith surface, which may provide a limited view of elemental distributions, a matter that has not previously been investigated. Imaging by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) permits microchemical analyses of short-term events in early life with high (< 10 μm) resolution, two-dimensional (2D) visualization of elemental distributions. To demonstrate the potential of this method, we mapped the concentrations of Sr and Ba, two key trace elements, in a small number of juvenile otoliths of neon damselfish (Pomacentrus coelestis) using an 8 μm beam diameter (laser fluence of 13.8 ± 3.5 J cm{sup −2}). Quantification was performed using the established method by Longerich et al. (1996), which is applied to 2D imaging of a biological matrix here for the first time. Accuracy of > 97% was achieved using a multi-point non matrix-matched calibration of National Institute of Standards and Technology (NIST) 610 and 612 (trace elements in glass) using Longerich's calculation method against the matrix-matched standard FEBS-1 (powdered red snapper [Lutjanus campechanus] otolith). The spatial resolution achieved in the otolith corresponded to a time period of 2 ± 1 days during the larval phase, and 4 ± 1 days during the post-settlement juvenile phase. This method has the potential to improve interpretations of early life-history events at scales corresponding to specific events. While the images showed gradients in Sr and Ba across the larval settlement zone more clearly than single transects, the method proved sample homogeneity throughout the structure; demonstrating that 2D

Paradigm Lost: Ocean Acidification Will Overturn the Concept of Larval-Fish Biophysical Dispersal

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Jeffrey M. Leis

2018-02-01

Full Text Available Most marine ecologists have in the past 25 years changed from supporting a passive-dispersal paradigm for larval marine fishes to supporting a biophysical-dispersal paradigm wherein the behaviour of larvae plays a central role. Research shows larvae of demersal perciform fishes have considerable swimming and orientation abilities over a major portion of their pelagic larval duration. These abilities depend on sensory function, and some recent research has indicated anthropogenic acidification of the oceans will by the end of the century result in sensory dysfunction. This could strongly alter the ability of fish larvae to orientate in the pelagic environment, to locate suitable settlement habitat, to bet-hedge, and to colonize new locations. This paper evaluates the available publications on the effects of acidification on senses and behaviours relevant to dispersal of fish early life-history stages. A large majority of studies tested CO2 values predicted for the middle to end of the century. Larvae of fourteen families—all but two perciform—were studied. However, half of studies used Damselfishes (Pomacentridae, and except for swimming, most studies used settlement-stage larvae or later stages. In spite of these taxonomic and ontogenetic restrictions, all but two studies on sensory function (chemosensation, hearing, vision, detection of estuarine cues found deleterious effects from acidification. The four studies on lateralization and settlement timing all found deleterious effects from acidification. No clear effect of acidification on swimming ability was found. If fish larvae cannot orientate due to sensory dysfunction, their dispersal will, in effect, conform to the passive dispersal paradigm. Modelling incorporating larval behaviour derived from empirical studies indicates that relative to active larvae, passive larvae will have less self-recruitment, higher median and mean dispersal distances, and lower settlement rates: further, bet

Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden.

Science.gov (United States)

Khalaf, Maroof A; Abdallah, Mohamed

2014-01-01

The spatial distribution of 50 ornamental fish species from shallow water habitats on coral reefs were investigated using visual census techniques, between latitudes 11-29°N in the Red Sea, in Jordan, Egypt, Saudi Arabia, and Yemen, and in the adjacent Gulf of Aden in Djibouti. One hundred eighteen transects (each 100×5 m) were examined in 29 sites (3-8 sites per country). A total of 522,523 fish individuals were counted during this survey, with mean abundance of 4428.2 ± 87.26 individual per 500 m² transect. In terms of relative abundance (RA), the most abundant species were Blue green damselfish, Chromis viridis (RA=54.4%),followed bySea goldie, Pseudanthias squamipinnis (RA= 34.7), Whitetail dascyllus, Dascyllus aruanus (RA= 2.6%), Marginate dascyllus, Dascyllus marginatus (RA= 2.0),Red Sea eightline flasher Paracheilinus octotaenia (RA=1.0),andKlunzinger's wrasse, Thalassoma rueppellii (0.7%). The highest number of species (S) per 500 m² transect was found on reefs at the latitude 20° in Saudi Arabia (S=21.8), and the lowest number of species was found at the latitude 15° in Djibouti (S=11.11). The highest mean abundance (8565.8) was found on reefs at latitude 20° in Saudi Arabia and the lowest mean abundance (230) was found on reefs at latitude 22°, also in Saudi Arabia. Whereas, the highest Shannon-Wiener Diversity Index was found in reefs at the latitude 22° (H`=2.4) and the lowest was found in reefs at the latitude 20° (H`=0.6). This study revealed marked differences in the structure of ornamental fish assemblages with latitudinal distribution. The data support the presence of two major biogeographic groups of fishes in the Red Sea and Gulf of Aden: the southern Red Sea and Gulf of Aden group and the group in the northern and central Red Sea. Strong correlations were found between live coral cover and the number of fish species, abundance and Shannon-Wiener Diversity indices, and the strength of these correlations varied among the reefs. A

Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden

Directory of Open Access Journals (Sweden)

Maroof Khalaf

2014-01-01

Full Text Available The spatial distribution of 50 ornamental fish species from shallow water habitats on coral reefs were investigated using visual census techniques, between latitudes 11−29°N in the Red Sea, in Jordan, Egypt, Saudi Arabia, and Yemen, and in the adjacent Gulf of Aden in Djibouti. One hundred eighteen transects (each 100×5 m were examined in 29 sites (3−8 sites per country. A total of 522,523 fish individuals were counted during this survey, with mean abundance of 4428.2 ± 87.26 individual per 500 m² transect. In terms of relative abundance (RA, the most abundant species were Blue green damselfish, Chromis viridis (RA=54.4%, followed by Sea goldie, Pseudanthias squamipinnis (RA= 34.7, Whitetail dascyllus, Dascyllus aruanus (RA= 2.6%, Marginate dascyllus, Dascyllus marginatus (RA= 2.0, Red Sea eightline flasher Paracheilinus octotaenia (RA=1.0, and Klunzinger’s wrasse, Thalassoma rueppellii (0.7%. The highest number of species (S per 500 m² transect was found on reefs at the latitude 20° in Saudi Arabia (S=21.8, and the lowest number of species was found at the latitude 15° in Djibouti (S=11.11. The highest mean abundance (8565.8 was found on reefs at latitude 20° in Saudi Arabia and the lowest mean abundance (230 was found on reefs at latitude 22°, also in Saudi Arabia. Whereas, the highest Shannon-Wiener Diversity Index was found in reefs at the latitude 22° (H`=2.4 and the lowest was found in reefs at the latitude 20° (H`=0.6. This study revealed marked differences in the structure of ornamental fish assemblages with latitudinal distribution. The data support the presence of two major biogeographic groups of fishes in the Red Sea and Gulf of Aden: the southern Red Sea and Gulf of Aden group and the group in the northern and central Red Sea. Strong correlations were found between live coral cover and the number of fish species, abundance and Shannon-Wiener Diversity indices, and the strength of these correlations varied among the

The evolution of pharyngognathy: a phylogenetic and functional appraisal of the pharyngeal jaw key innovation in labroid fishes and beyond.

Science.gov (United States)

Wainwright, Peter C; Smith, W Leo; Price, Samantha A; Tang, Kevin L; Sparks, John S; Ferry, Lara A; Kuhn, Kristen L; Eytan, Ron I; Near, Thomas J

2012-12-01

The perciform group Labroidei includes approximately 2600 species and comprises some of the most diverse and successful lineages of teleost fishes. Composed of four major clades, Cichlidae, Labridae (wrasses, parrotfishes, and weed whitings), Pomacentridae (damselfishes), and Embiotocidae (surfperches); labroids have been an icon for studies of biodiversity, adaptive radiation, and sexual selection. The success and diversification of labroids have been largely attributed to the presence of a major innovation in the pharyngeal jaw apparatus, pharyngognathy, which is hypothesized to increase feeding capacity and versatility. We present results of large-scale phylogenetic analyses and a survey of pharyngeal jaw functional morphology that allow us to examine the evolution of pharyngognathy in a historical context. Phylogenetic analyses were based on a sample of 188 acanthomorph (spiny-rayed fish) species, primarily percomorphs (perch-like fishes), and DNA sequence data collected from 10 nuclear loci that have been previously used to resolve higher level ray-finned fish relationships. Phylogenies inferred from this dataset using maximum likelihood, Bayesian, and species tree analyses indicate polyphyly of the traditional Labroidei and clearly separate Labridae from the remainder of the traditional labroid lineages (Cichlidae, Embiotocidae, and Pomacentridae). These three "chromide" families grouped within a newly discovered clade of 40 families and more than 4800 species (>27% of percomorphs and >16% of all ray-finned fishes), which we name Ovalentaria for its characteristic demersal, adhesive eggs with chorionic filaments. This fantastically diverse clade includes some of the most species-rich lineages of marine and freshwater fishes, including all representatives of the Cichlidae, Embiotocidae, Pomacentridae, Ambassidae, Gobiesocidae, Grammatidae, Mugilidae, Opistognathidae, Pholidichthyidae, Plesiopidae (including Notograptus), Polycentridae, Pseudochromidae

Benthic and fish population monitoring associated with a marine protected area in the nearshore waters of Grenada, Eastern Caribbean

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Robert Anderson

2012-03-01

Full Text Available Annual benthic and fish population surveys were completed at five locations in the nearshore waters along Grenada´s southwest coast during 2008-2010. Two survey sites are located in a newly launched Marine Protected Area (MPA. Photo Quadrat (PQ and Point Line Intercept (PLI surveys were used to determine substrate cover. Algae was the primary live cover increasing significantly from 45.9% in 2008 to 52.7% in 2010 (PLI. Algae was also predominant (61.0%-59.3% in the PQ surveys although annual variation was not significant. Hard coral cover ranged from 16.5% to 15.4% (PLI and 11.4% to12.0% (PQ with no significant differences between years. Branching and encrusting corals occurred more frequently than massive corals. In the three annual surveys neither algal cover nor hard coral varied significantly between MPA and non-protected areas (PLI. Relative abundance of fishes along 30x2m belt transects did not vary significantly among years however density of fishes decreased significantly across years for most major groups. Chromis spp. dominated the survey sites at 65.2% in 2008 and 49.8% in 2010, followed by territorial damselfish,11.1% and 15.5%, wrasse increased from 7.3% to 15.5%. Both the substrate cover and fish survey data analyses indicated a stable but degraded community. Annual surveys are planned at these sites for the foreseeable future. Existing and future data from this project will be valuable in determining the efficacy of MPA management, guiding resource management decisions and monitoring the health status of Grenada’s valuable reef systemsUn estudio sobre poblaciones bentónicas y de peces fue realizado en cinco localidades en la zona costera en el suroeste de Grenada entre 2008 y 2010. Dos sitios se ubicaron en una Área Marina Portegida (AMP recientemente creada. Para determinar la cobertura se utilizaron foto-cuadrantes (FQ y transectos de intersección de puntos (TIP. Las algas fueron el principal componente del bentos

The importance of the marine ornamental reef fish trade in the wider Caribbean

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A.W Bruckner

2005-05-01

Full Text Available The marine ornamental fish trade began in the 1930s in Sri Lanka,spread to Hawaii and the Philippines in the 1950s,and expanded to a multi-million dollar industry in the 1970s with fisheries established throughout the tropical Pacific,Indian and Atlantic Oceans.Currently,45 countries supply global markets an estimated 14-30 million fish annually,with an import value of US$28-44 million.The largest suppliers are Indonesia and the Philippines,followed by Brazil,Maldives,Vietnam,Sri Lanka and Hawaii.In the tropical Western Atlantic,16 countries have export fisheries, including the U.S.(Florida and Puerto Rico.The U.S.is the world ’s largest buyer,followed by the European Union and Japan.The global trade consists of over 1400 species of reef fishes,of which only about 25 are captive bred on a commercial scale.Damselfish,anemonefish, and angelfish constitute over 50%of the global volume; butterflyfish, wrasses,blennies,gobies,triggerfish,file-fish,hawkfishes,groupers and basselets account for 31%of the trade,and the remaining 16%is represented by 33 families.The most important fishes from the Caribbean are angelfish (six species, seahorses (two species, royal gramma, jawfish,queen triggerfish,redlip blenny,puddingwife,bluehead wrasse,and blue chromis.The Caribbean currently supplies a small percentage of the global trade in marine ornamental species,but ornamental fisheries in this region represent important emerging industries.It is critical that effective ornamental fishery management plans and regulations are developed and enforced,and fishery-dependent and fishery-independent data are collected and utilized in decision making processes to ensure sustainable ornamental fisheries throughout the region.El comercio de peces marinos ornamentales se inició en la década de 1930 en Sri Lanka y se extendió a Hawai y Las Filipinas en la década de 1950.Posteriormente se convirtió en una industria multimillonaria cuando,en la década de 1970,se

Efecto de la herbivoría y coralivoría por peces en la supervivencia de corales trasplantados en el Caribe colombiano

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Luis Chasqui-Velasco

2007-12-01

mortality in some colonies, mainly of P. astreoides. No significant difference in healthy tissue percentages among full-cage and uncaged colonies on M. annularis and D. labyrinthiformis was found, while in P. astreoides there were evident differences. The results indicate a damselfish negative effect on transplants survival early on the study, which can change depending on the fish and coral species involved. Results also indicate a fish grazing positive effect, caused by the reduction of coral-algae competition pressure, mainly on P. astreoides. Parrotfishes seem to affect corals survival both negatively through direct biting, and positively by controlling algal growth. Overall, coral transplant success was almost unaffected by fish foraging activity although several differences among coral species were obvious in relation to colony shape. Additionally, the interaction among herbivorous fish grazing and coral-algae competition balance appear important in determining transplant survival. Rev. Biol. Trop. 55 (3-4: 825-837. Epub 2007 December, 28.