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The change in coral reefs from live coral to algal-dominated seascapes prevents some fish species from using chemical alarm cues to gain information about their risk of predation. Field experiments showed that Ambon damselfish, Pomacentrus amboinensis , were able to learn the identity of individual novel predators from a cocktail of odours from three predators derived from digestive products. Learning only occurred when the predators had been fed conspecifics of the prey species in the presence of water that had passed over live hard coral. This allows novel predators to be identified long after the immediate capture and ingestion event. Fish that had the same learning opportunity in degraded water took more risk and died faster on habitat patches in the field. Ambon damselfish respond to chemical alarm cues from closely related Pomacentrus nagasakiensis , in both live and degraded water, yet experiments suggested they cannot use the congeneric diet odours to label predators. However, we did find a modest survival benefit under natural conditions, suggesting some limited learning occurred. Findings suggest that as coral habitats degrade, fishes that are affected by the changing chemistry will have a greatly reduced range of mechanisms for obtaining and updating threat information, altering the resilience of communities. • Risk assessment of fishes can change when coral reefs become degraded. • Some species can no longer use chemical alarm cues to inform, learn and update risk. • Diet odours from predators were a useful way of labelling novel predator smells. • Diet odours only worked in live coral water and not water from degraded coral. • Fish conditioned on degraded coral took more risks and died faster in the field. [ABSTRACT FROM AUTHOR]

The large caerulean damselfish, Pomacentrus caeruleopunctatus Allen, 2002, is recorded for the first time from Reunion Island. Two individuals were observed and photographed between January and March 2012 on L'Hermitage reef, located on the west coast of the island. A review of high-resolution profile photographs of these two individuals shows that their external morphological characteristics agree well with those reported in the original description of the species. These observations suggest an extension of the known distribution of the species, previously restricted to the Seychelles Islands, Madagascar, and Tanzania, to the Mascarene Archipelago, and moreover the known depth range of this species. [ABSTRACT FROM AUTHOR]

A new species of damselfish, Pomacentrus bellipictus, is described from 13 specimens, 37.7-67.9 mm SL, collected at the Kokas area of the Fakfak Peninsula, a portion of the Bird's Head Peninsula of western New Guinea (West Papua Province, Indonesia). It is distinguished from most similar species in the western Pacific Ocean by having 14 instead of 13 dorsal-fin spines. It also possesses a unique facial coloration consisting of highly contrasted blue areas around the mouth and onto the isthmus, below the eye, and along the margin of the preopercle. The only other species of Pomacentrus from the region with 14 dorsal spines that are also drab-brown when alive, P. fakfakensis and P. opisthostigma, are clearly distinguished on the basis of adult and juvenile color patterns and also show different habitat preferences. In addition, P. opisthostigma is distinguished from the other two species by fewer lateral-line scales (usually 15-17 vs. usual 18-19) and more gill rakers on the first arch (26-29 vs. 18-21). The three species co-occur in the Kokas area, but occupy different habitats: Pomacentrus bellipictus inhabits rocky, wave-washed shorelines in about 1-2 m depth, while the other two species occur in deeper water. The new species is apparently endemic to the small area around the Fakfak Peninsula, where several other microendemic reef fish species have been described. [ABSTRACT FROM AUTHOR]

Most studies investigating the effects of anthropogenic environmental stressors do so in conditions that are often optimal for their test subjects, ignoring natural stressors such as competition or predation. As such, the quantitative results from such studies may often underestimate the lethality of certain toxic compounds. A well-known example of this concept is illustrated by the marked increase in the lethality of pesticides when larval amphibians are concurrently exposed to the odor of potential predators. Here, we investigated the interaction between background levels of environmental predation risk (high vs. low) and ocean acidification (ambient vs. elevated CO2) in 2 × 2 design. Wild-caught juvenile damselfish, Pomacentrus amboinensis, were exposed in the laboratory to the different risk and CO2 conditions for 4 days and released onto coral reef patches. Using a well-established field assay, we monitored the in situ behavior and mortality of the damselfish for 2 days. We predicted that juvenile fish exposed to elevated CO2 and high-risk conditions would display more severe behavioral impairments and increased mortality compared to fish exposed to elevated CO2 maintained under low-risk conditions. As expected, elevated CO2 exposure led to impaired antipredator responses and increased mortality in low-risk fish compared to ambient CO2 controls. However, we failed to find an effect of elevated CO2 on the behavior and survival of the high-risk fish. We hypothesized that the results may stem from either a behavioral compensation or a physiological response to high risk. Our results provide insights into the interactive nature of environmental and natural stressors and advance our understanding of the predicted effect of ocean acidification on aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Pomacentrus flavioculus n. sp. is described on the basis of 140 specimens, 17.1-86.8 mm SL, from Fiji and Tonga in the South Pacific Ocean. The new species was formerly identified as Pomacentrus imitator (Whitley, 1964), which now appears to be restricted to the Coral Sea. The new species clearly differs from P. imitator on the basis of several color-pattern features, including a bright yellow ring that encircles the pupil, a more uniform body color (vs. contrasting pale scale centers and dark scale margins), a yellowish caudal fin (vs. whitish), and a small orange marking immediately above the large black spot that covers the pectoral-fin base (absent in P. imitator). Although meristic and morphological features are broadly similar, P. flavioculus has a strong mode of 14 anal-fin rays vs. 15 in P. imitator. Additionally, P. flavioculus usually has a greater preanal distance and almost always has a longer pelvic-fin spine. A phylogenetic analysis of concatenated mtDNA sequences shows the new species is 8.4% divergent (average pairwise distance) from its nearest relatives and is part of the broad Pomacentrus philippinus species complex. [ABSTRACT FROM AUTHOR]

Damselfish are prolific callers, identified as being able to produce different kinds of sounds (pops and chirps) associated with various behaviors. During courtship and chase behaviors, the coral reef damselfish Pomacentrus amboinensis produces a previously unknown additional kind of call that we have named the wiping sound. These calls have two to three long (54 ± 13 ms) units that do not show the usual percussive aspect of the pomacentrid sounds. Calls consist of a high-pitched (from 550 to 775 Hz) tonal sound in which the cycle repetition rate corresponds to the peak frequency. The high frequency of this tonal sound can be excluded as coming from the contraction of sound producing muscles. These sounds could be the result of a mechanism that drives the merging of successive pops. In the noisy environment of coral reefs and the resulting competition for acoustic space, the wiping sounds appear to be a good way to increase signal distinctiveness and opportunities for correct signal discrimination. This new kind of sound supports that acoustic communication is highly important in the biology of damselfishes and their diversification. [ABSTRACT FROM AUTHOR]

The ability of two common, site-attached coral-reef fishes to return to their home corals after displacement was investigated in a series of field experiments at One Tree Island, southern Great Barrier Reef. The humbug Dascyllus aruanus was displaced up to 250 m, with 42% of individuals returning home, irrespective of body size, displacement, direction (up or across currents) and route complexity, while for the lemon damselfish Pomacentrus moluccensis 35% of individuals returned overall, with 33% from the greatest displacement, 100 m along a reef edge. Given that the home range of both species is <1 m2, over their 10+ year life span, the mechanisms and motivations for such homing ability are unclear but it may allow resilience if fishes are displaced by storm events, allowing rapid return to home corals. [ABSTRACT FROM AUTHOR]

Habitat degradation is a global problem and one of the main causes of biodiversity loss. Though widespread, the mechanisms that underlie faunal changes are poorly understood. In tropical marine systems, corals play a crucial role in forming habitat, but coral cover on many reefs is declining sharply. Coral degradation affects the olfactory cues that provide reliable information on the presence and intensity of threat. Here, we show for the first time that the ability of a habitat generalist to learn predators using an efficient and widespread method of predator learning is compromised in degraded coral habitats. Results indicate that chemical alarm cues are no longer indicative of a local threat for the habitat generalist (the damselfish, Pomacentrus amboinensis), and these cues can no longer be used to learn the identity of novel predators in degraded habitats. By contrast, a rubble specialist and congeneric (Pomacentrus coelestis) responded to olfactory threat cues regardless of background environment and could learn the identity of a novel predator using chemical alarm cues. Understanding howsome species can cope with or acclimate to the detrimental impacts of habitat degradation on risk assessment abilities will be crucial to defining the scope of resilience in threatened communities. [ABSTRACT FROM AUTHOR]

Settlement is a key life history transition for coral reef fishes, and how long a fish spends close to a reef prior to settlement is poorly understood. We used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and otolith microstructure analysis (daily increments and settlement marks) to determine the length of time larval fish spend near a reef prior to settlement. The otoliths of Pomacentrus amboinensis collected from four neighbouring reefs in the southern Great Barrier Reef showed clear and consistent differences in their elemental signatures prior to and following settlement. Elevated Ba:Ca near settlement and post-settlement was found in fish from all four reefs. However, there was individual variation in elemental profiles, with an increased otolith Ba-to-Ca ratio (near-reef signature) at settlement in 33 % of fish, and up to 8 d prior to settlement in others. Increment widths, often used as a proxy for growth, decreased approaching the settlement mark for all fish, providing further evidence for a 'search phase' in larvae. We demonstrated experimentally that otoliths of fish kept in reefal or inter-reefal waters had different elemental chemistry. There were differences in the elemental composition of water samples within the study area, but no consistent trends with distance from reefs. There was poor discrimination of multi-element signatures among fish from different reefs during their pre-settlement phases. However, discrimination improved in the settlement and post-settlement phases of otoliths, indicating that reef waters and perhaps stage of ontogeny affected otolith chemistry. This study demonstrated clear near-reef elemental signatures in fish around settlement. We suggest these differences are due to a combination of water chemistry and physiological influences (e.g., growth). Combining LA-ICP-MS with otolith microstructure analysis can provide high-resolution information on the early life history of reef fishes. Further, a near-reef 'search phase' prior to settlement may be common in reef fishes. [ABSTRACT FROM AUTHOR]

Trade-offs between traits that influence an individual's competitive ability are important in determining community assembly and coexistence of individuals sharing the same resources. Populations of coral reef fish are structurally complex, so it is important to understand how these populations are shaped as a result of an individual's suite of traits and those of its competitors. We conducted a 2 × 2 factorial field experiment that manipulated body condition (high or low, manipulated through a feeding regime) and residency (resident or intruder, where the resident arrived at the habitat 3 h before the intruder) to evaluate effects on competitive ability and survival. Prior residency alleviated the disadvantage of a low body condition with respect to aggression, which was similar between low-condition residents and high-condition intruders. However, high-condition residents displayed a significantly greater level of aggression than intruders, regardless of whether intruders were from high- or low-condition treatments. For intruders to have a high probability of becoming dominant, they needed to have a large body condition advantage. Mortality trajectories suggested that body condition modified the effect of prior residency, and intruders were more likely to suffer mortality if they had a low body condition because residents pushed them away from shelter. Our results highlight that the negative effects of some traits may be compensated for by the positive effects of other traits, and that the specific ecological context an individual faces (such as the characteristics of its competitors) can have a major influence on successful establishment and persistence. [ABSTRACT FROM AUTHOR]

Turf algae are a very important component of coral reefs, featuring high growth and turnover rates, whilst covering large areas of substrate. As food for many organisms, turf algae have an important role in the ecosystem. Farming damselfish can modify the species composition and productivity of such algal assemblages, while defending them against intruders. Like all organisms however, turf algae and damselfishes have the potential to be affected by future changes in seawater (SW) temperature and pCO2. In this study, algal assemblages, in the presence and absence of farming Pomacentrus wardi were exposed to two combinations of SW temperature and pCO2 levels projected for the austral spring of 2100 (the B1 “reduced” and the A1FI “business-as-usual” CO2 emission scenarios) at Heron Island (GBR, Australia). These assemblages were dominated by the presence of red algae and non-epiphytic cyanobacteria, i.e. cyanobacteria that grow attached to the substrate rather than on filamentous algae. The endpoint algal composition was mostly controlled by the presence/absence of farming damselfish, despite a large variability found between the algal assemblages of individual fish. Different scenarios appeared to be responsible for a mild, species specific change in community composition, observable in some brown and green algae, but only in the absence of farming fish. Farming fish appeared unaffected by the conditions to which they were exposed. Algal biomass reductions were found under “reduced” CO2 emission, but not “business-as-usual” scenarios. This suggests that action taken to limit CO2 emissions may, if the majority of algae behave similarly across all seasons, reduce the potential for phase shifts that lead to algal dominated communities. At the same time the availability of food resources to damselfish and other herbivores would be smaller under “reduced” emission scenarios. [ABSTRACT FROM AUTHOR]

Pleistocene eustatic changes in sea level are often invoked to explain genetic divergence among marine organisms. However, molecular phylogenies have revealed relatively few examples of speciation events dating to the Pleistocene. We present a species-level hypothesis of the timing of evolution for the Pomacentrus coelestis species complex (Pomacentridae), based on the nuclear S7 intron and the mitochondrial Cytb gene, and reconstruct ancestral range distributions across the timetree. Ancestral range reconstruction suggests the complex originated in the Coral Triangle and East Indian Ocean, with subsequent range expansion outward from this region. We suggest that land barriers to dispersal (e.g., Indo-Pacific barrier) may be responsible for the divergence between Indian ( P. alleni, P. similis, P. caeruleopunctatus, and P. caeruleus) and Pacific ( P. micronesicus, P. auriventris, and P. coelestis) species groups, and subsequent isolation by Pleistocene sea-level fluctuations in certain areas of the Coral Triangle (glacial refugia) may play an important role in the diversification of this species complex. Additionally, our analyses show cryptic lineages within P. micronesicus and highlight the need for comprehensive sampling within and among species to reveal recent speciation events. [ABSTRACT FROM AUTHOR]

The pulsed nature of new individuals entering into existing communities means that prior residents can greatly influence the establishment and persistence of later-arriving individuals. The unique set of interactions experienced by an individual can also affect how it behaves and its likelihood of winning future encounters. In the present study, we used field experiments to investigate the circumstances under which residency (resident or intruder), behavioural history (prior dominance or subordinance) and body size determined the direction and strength of intraspecific interactions. We paired recently metamorphosed individuals of a coral reef damselfish, Pomacentrus amboinensis, with different suites of these traits to observe how each behaved in a competitive interaction. Our results show the importance of priority and size advantages, and suggest that prior behavioural history has the least influence on the outcome of future confrontations. Prior history was only important when combatants were of similar size, with previously subordinate residents losing against similarly sized previously dominant intruders. Aggression affected space use on a habitat patch and was itself affected by the relative size difference between combatants. Aggressive residents were larger than their competitors, occupied higher areas of the patch and chased intruders to lower areas of the patch and further away from the patch. Space use was not affected by behavioural history. These results demonstrate the importance of priority effects in structuring fish communities, and how an individual's physical and behavioural characteristics interact to predict community dynamics. This has important implications for predicting fish community structure under certain environmental or ecological scenarios. [Copyright &y& Elsevier]

The theory of behavioral syndromes focuses on quantifying variation in behavior within and among individual organisms and attempts to account for the maintenance of differences in behavior that occur in a consistent manner among individuals. Behavioral syndromes have potentially important ecological consequences (e.g. survivorship tradeoffs) and can be shaped by population dynamics through selective mortality. Here, we search for any evidence for consistency of behavior across situations in juveniles of a common damselfish, Pomacentrus amboinensis (Pomacentridae) at the transition between larval habitats in the plankton and juvenile habitats on the reef. Naïve fish leaving the pelagic phase to settle on reefs were caught by light traps and their behaviors observed using similar methods across three different situations (small aquaria, large aquaria, field setting); all of which represent low risk and well-sheltered environments. Seven behavioral traits were compared within and among individuals across situations to determine if consistent behavioral syndromes existed. No consistency was found in any single or combination of behavioral traits for individuals across all situations. We suggest that high behavioral flexibility is likely beneficial for newly-settled fish at this ontogenetic transition and it is possible that consistent behavioral syndromes are unlikely to emerge in juveniles until environmental experience is gained or certain combinations of behaviors are favored by selective mortality. [ABSTRACT FROM AUTHOR]

Tropical species are predicted to have limited capacity for acclimation to global warming. This study investigated the potential for developmental thermal acclimation by the tropical damselfish Pomacentrus moluccensis to ocean temperatures predicted to occur over the next 50-100 years. Newly settled juveniles were reared for 4 months in four temperature treatments, consisting of the current-day summer average (28.5 °C) and up to 3 °C above the average (29.5, 30.5 and 31.5 °C). Resting metabolic rate (RMR) of fish reared at 29.5 and 31.5 °C was significantly higher than the control group reared at 28.5 °C. In contrast, RMR of fish reared at 30.5 °C was not significantly different from the control group, indicating these fish had acclimated to their rearing temperature. Furthermore, fish that developed in 30.5 and 31.5 °C exhibited an enhanced ability to deal with acute temperature increases. These findings illustrate that developmental acclimation may help coral reef fish cope with warming ocean temperatures. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Delineating barriers to connectivity is important in marine reserve design as they describe the strength and number of connections among a reserve's constituent parts, and ultimately help characterize the resilience of the system to perturbations at each node. Here we demonstrate the utility of multi-taxa phylogeography in the design of a system of marine protected areas within Fiji. Gathering mtDNA control region data from five species of coral reef fish in five genera and two families, we find a range of population structure patterns, from those experiencing little (Chrysiptera talboti, Halichoeres hortulanus, and Pomacentrus maafu), to moderate (Amphiprion barberi, Φst = 0.14 and Amblyglyphidodon orbicularis Φst = 0.05) barriers to dispersal. Furthermore estimates of gene flow over ecological time scales suggest species-specific, asymmetric migration among the regions within Fiji. The diversity among species-specific results underscores the limitations of generalizing from single-taxon studies, including the inability to differentiate between a species-specific result and a replication of concordant phylogeographic patterns, and suggests that greater taxonomic coverage results in greater resolution of community dynamics within Fiji. Our results indicate that the Fijian reefs should not be managed as a single unit, and that closely related species can express dramatically different levels of population connectivity. [ABSTRACT FROM AUTHOR]

Coral reef Fishes is one of bio-indicators for good condition coral reef ecosystem. A study on coral reef fishes in the Kendari waters was aimed to find out species composition, abundance, distribution and community structure of coral reef fishes in that area. The study was conducted in July 2011 at five locations on the northern and southern part of Kendari waters. Data were gathered using SCUBA with underwater visual census (UVC) and line transect (Line Intersept Transect, LIT methods). A total of 111 species of 24 families of coral reef fishes were gathered, consisted of 31 species of target fishes, 17 indicator species and 63 species of major group fishes. The target fishes were dominated by Caesio cuning, Siganus vulpinus and Ctenochaetus striatus. Indicator species was dominated by Chaetodon octofasciatus and major group fishes were dominated by Pomacentrus smithii, Chrysiptera rollandi, Chrysiptera springeri, and Pomacentrus alexandera.The Shannon-Wiener diversity indices were ranged between 1.36 and 3.23, the Margalefs index of richness ranged from 4.74 and 8,66 while Evenness indices of Pielou were ranged from 0.38 to 0.81. The cluster analysis of Bray Curtis index of simmilarity showed two groups on the dendogram at 37% similarity level, while the multidimensional similarity analysis (stress = 0) was also shown two different communities. The result of the study could be useful to baseline data to coastal management area to local government authority (PEMDA). [ABSTRACT FROM AUTHOR]

Predation plays a major role in shaping prey behaviour. Temporal patterns of predation risk have been shown to drive daily activity and foraging patterns in prey. Yet the ability to respond to temporal patterns of predation risk in environments inhabited by highly diverse predator communities, such as rainforests and coral reefs, has received surprisingly little attention. In this study, we investigated whether juvenile marine fish, Pomacentrus moluccensis (lemon damselfish), have the ability to learn to adjust the intensity of their antipredator response to match the daily temporal patterns of predation risk they experience. Groups of lemon damselfish were exposed to one of two predictable temporal risk patterns for six days. "Morning risk" treatment prey were exposed to the odour of Cephalopholis cyanostigma (rockcod) paired with conspecific chemical alarm cues (simulating a rockcod present and feeding) during the morning, and rockcod odour only in the evening (simulating a rockcod present but not feeding). "Evening risk" treatment prey had the two stimuli presented to them in the opposite order. When tested individually for their response to rockcod odour alone, lemon damselfish from the morning risk treatment responded with a greater antipredator response intensity in the morning than in the evening. In contrast, those lemon damselfish previously exposed to the evening risk treatment subsequently responded with a greater antipredator response when tested in the evening. The results of this experiment demonstrate that P. moluccensis have the ability to learn temporal patterns of predation risk and can adjust their foraging patterns to match the threat posed by predators at a given time of day. Our results provide the first experimental demonstration of a mechanism by which prey in a complex, multi-predator environment can learn and respond to daily patterns of predation risk. [ABSTRACT FROM AUTHOR]

Ocean acidification has the potential to cause dramatic changes in marine ecosystems. Larval damselfish exposed to concentrations of CO2 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 CO2 effects, whereby some individuals are unaffected at particular CO2 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 CO2 (current day levels) or 850 μatm CO2, 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 CO2 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 matm-CO2 fish to learn to recognize a dottyback as a predator using injured conspecific cues, as in Experiment 1. When tested one day postconditioning, CO2 exposed fish failed to respond to predator odour. When tested 5 days post-conditioning, CO2 exposed fish still failed to show an antipredator response to the dottyback odour, despite the fact that both control and CO2-treated fish responded to a general risk cue (injured conspecific cues). These results indicate that exposure to CO2 may alter the cognitive ability of juvenile fish and render learning ineffective. [ABSTRACT FROM AUTHOR]

Making the appropriate decision in the face of predation risk dictates the fate of prey, and predation risk is highest at life history boundaries such as settlement. At the end of the larval phase, most coral reef fishes enter patches of reef containing novel predators. Since vision is often obscured in the complex surroundings, chemical information released from damaged conspecific is used to forewarn prey of an active predator. However, larvae enter the reef environment with their own feeding and growth histories, which will influence their motivation to feed and take risks. The present study explored the link between recent growth, feeding history, current performance and behavioural risk taking in newly settling stages of a coral reef damselfish ( Pomacentrus amboinensis). Older and larger juveniles in good body condition had a stronger response to chemical alarm cues of injured conspecifics; these fish spent a longer time in shelter and displayed a more dramatic decrease in foraging behaviour than fish in lower body condition. Feeding experiments supported these findings and emphasized the importance of body condition in affecting risk assessment. Evidently, larval growth history and body condition influences the likelihood of taking risks under the threat of predation immediately after settlement, thereby affecting the probability of survival in P. amboinensis. [ABSTRACT FROM AUTHOR]

Prey that respond to inappropriate cues in their assessment of predation risk spend more time performing defensive behaviours and less time undertaking behaviours that promote fitness. Hence, prey should respond to cues that are the best predictors of predation risk relevant to the prey individual. Many fish undergo ontogenetic shifts in habitat and resource use during their lifetime; consequently, prey fish are exposed to a variety of predators at different stages of their development. Also, as relative concentration of the alarm cue represents both spatial and temporal information about a predation event, prey should adjust the intensity of their antipredator response in a threat-sensitive manner. We found that the ambon damselfish, Pomacentrus amboinensis, exhibited a threat-sensitive response to damage-released cues of conspecifics, with the magnitude of the response dependent on the cue concentration. Higher cue concentrations (suggesting a greater threat) elicited a stronger avoidance response, while low cue concentrations (weak threats) elicited a weak antipredator response. Moreover, the nature of the response depended on the ontogenetic stage of the cue donor. Reef-naïve recruit individuals exhibited consistent antipredator behaviours when exposed to alarm cue concentrations from individuals of the same ontogenetic stage, modest antipredator responses to juvenile skin extracts, and no antipredator behaviours when exposed to cues from adult fish. Individuals that alter their avoidance response in a manner that reflects the magnitude of risk successfully balance the trade-off between defensive and risky or fitness-promoting behaviours, and natural selection would presumably favour these individuals. [Copyright &y& Elsevier]

Settlement-stage larvae of the coral reef fishes Ostorhinchus doederleini (Apogonidae) and Pomacentrus coelestis (Pomacentridae) prefer the odor of their settlement reef to that of other nearby reefs. It was unknown whether these olfactory preferences are temporally stable or the result of recent olfactory experience. Ostorhinchus doederleini and P. coelestis larvae were held in aquaria and exposed to water from either their settlement reef or a neighboring reef for 5-9 days and their olfactory preference was tested. We show that exposure to water from another reef did not influence olfactory preference. Ostorhinchus doederleini olfactory preference declined slightly over time whereas P. coelestis preference was gradually lost after 2-3 days in captivity. Neither species switched their preference to the new reef odor. While we cannot determine conclusively the time window of odor learning, imprinting at or shortly after birth is logical and has been demonstrated in other fish species. [ABSTRACT FROM AUTHOR]

How individuals respond to predation threats will have a large influence on which individuals survive within a population. The magnitude and timing of these responses will be particularly important during periods of high predation susceptibility, such as that experienced by coral reef fishes immediately following settlement to the reef environment. Although reef fish are known to adopt certain antipredator behaviours when exposed to chemical alarm scents during this early period, the role of visual cues, and how the response varies with different levels of predation threat (both olfactory and visual), remains unknown. This study examined the behavioural response of a newly settled coral reef fish (Pomacentrus amboinensis) to different levels of an olfactory and visual predation threat. The concentration of a conspecific chemical alarm cue and the visual proximity to a potential predator (Pseudochromis fuscus) were manipulated in separate aquarium experiments. Behavioural responses were found to be threat sensitive in nature, with higher-level threat cues eliciting a more intense response. Although significant changes were observed, responses to visual cues were more inconsistent, while responses to extremely low chemical cue concentrations were marginal, indicating a possible threshold lower limit. These findings demonstrate the ability of newly settled fish to assess the level of predation risk using both visual and chemical cues, and respond appropriately. [Copyright &y& Elsevier]

Variation in planktonic larval duration (PLD) and growth of Pomacentrus coelestis was investigated on the southern Great Barrier Reef at multiple spatial scales. A tetracycline experiment, using presettlement fish, demonstrated that increments were formed daily. Variation in PLD was low between reef clusters (0%), reefs within clusters (0.4-8.5%) and sites within reefs (13.1%), but high among individuals within sites (86.5-91.5%); PLD ranged from 15 to 27 days. It was predicted that PLD would vary at greater spatial scales, but differences were low and a review of all studies on P. coelestis in tropical waters had a similar range of PLDs to our study. Contrary to a hypothesis that fish with slower growth would have longer PLDs, there was no significant relationship between mean presettlement increment width of otoliths and PLD for fish from the two reef clusters examined. There were, however, differences in presettlement growth rates between reef clusters (over 100 km apart) over the last 5-6 days of planktonic life. Warmer waters at the Swain Reefs (0.1-1°C) may have contributed to these differences in growth. Stochastic transport of larvae, habitat choice by presettlement fish in a reef mosaic, and variable conditions in the plankton may contribute to variation in PLD, presettlement growth and size-at-settlement in P. coelestis. We propose that prolonged periods of settlement choice may obscure simple relationships between PLD and size-at-settlement. [ABSTRACT FROM AUTHOR]

Settlement from the plankton ends the major dispersive stage of life for many marine organisms and exposes them to intense predation pressure in juvenile habitats. This predation mortality represents a life-history bottleneck that can determine recruitment success. At the level of individual predator–prey interactions, prey survival depends upon behavior, specifically how behavior affects prey conspicuousness and evasive ability. We conducted an experiment to identify behavioral traits and performance levels that are important determinants of which individuals survive or die soon after settlement. We measured a suite of behavioral traits on late stage, pre-settlement Ward's damsel ( Pomacentrus wardi) collected using light traps. These behavioral traits included two measures of routine swimming (indicators of conspicuousness) and eight measures of escape performance to a visual startle stimulus. Fish were then released onto individual patch reefs, where divers measured an additional behavioral trait (boldness). We censused each patch reef until approximately 50% of the fish were missing (~24 h), which we assumed to be a result of predation. We used classification tree analysis to discriminate survivors from fish presumed dead based on poor behavioral performance. The classification tree revealed that individuals displaying the maladaptive combination of low escape response speed, low boldness on the reef, and high routine swimming speed were highly susceptible to predation (92.4% with this combination died within 24 h). This accounted for 55.2% of all fish that died. Several combinations of behavioral traits predicted likely survival over 24 h, but there was greater uncertainty about that prediction than there was for fish that were predicted to die. Thus maladaptive behavioral traits were easier to identify than adaptive traits. [ABSTRACT FROM AUTHOR]

The article discusses the impact of behavioral traits on the survival of the tropical Pomacentrus wardi, a type of damselfish commonly found in the shallow reefs of the Indo-Pacific. In the study, the damselfish were subject to several types of transient and resident predators including, but not limited to, Synodus variegatus, Pseudochromis fuscus and Thalassoma lunare. Results revealed the loss of 59 percent of experimental individuals on the first day and also indicated the correlation of mortality to larval growth and characteristics.

Trade-offs between the costs and benefits of growth are thought to be mediated by behaviour, whereby rapid growth is associated with greater predation mortality because of increased foraging effort. We tested this hypothesis by collecting young Pomacentrus amboinensis using light traps and settling them onto patch reefs where their behaviour and survivorship were monitored for 24h. One month later, individuals of the same cohort were collected from shallow reefs and released onto patch reefs where their behaviour and survivorship were monitored for 6 days. At settlement young fish suffered high (60% in 24h) mortality that preferentially removed larger, faster-growing individuals. However, we could find no evidence that foraging behaviour contributed to this selective mortality. In contrast, 1 month later the same cohort underwent negative size-selective mortality where the smallest, slower-growing fish were preferentially removed by predators. Larger fish spent more time foraging, were more aggressive, swam greater distances and chased more fish than smaller individuals. Thus, consistent individual differences in behaviour contributed to patterns of mortality, but in a way that involved no apparent trade-off with growth. For P. amboinensis, consistent variation in growth may be maintained by spatial and temporal differences in the selective regime within the reef environment. [Copyright &y& Elsevier]

The article presents a study on the recruitment and persistence of coral-dwelling fishes at a natural coral bleaching event in Kimbe Bay, Papua New Guinea. The research involves tagging the healthy, severely bleached, and dying colonies of corymbose Acropora species (spp.), and monitoring its resident fish communities. There was no difference in the mean number of Pomacentrus moluccensis recruits that settled on healthy versus bleached corals, but the number of recruits on dead colonies was lower after 4 weeks and the frequency of recruit selection was lower on dead colonies. Furthermore, the results show that coral-dwelling fishes do not avoid bleached corals at settlement but will quickly disappear if corals die from bleaching.

The present study provides the first analysis of the feeding macroecology of territorial damselfishes (Perciformes: Pomacentridae), a circumtropical family whose feeding and behavioral activities are important in structuring tropical and subtropical reef benthic communities. The analyses were conducted from data collected by the authors and from the literature. A strong positive correlation was observed between bite rates and sea surface temperature (SST) for the genus Stegastes. A negative correlation was found between bite rates and mean body size for the genera Stegastes and Pomacentrus, but this relationship was not significant when all territorial pomacentrids were analyzed together. A negative correlation between body size and SST was observed for the whole group and for the genera Stegastes, and Pomacentrus. No relationship was found between territory size and feeding rates. Principal Components Analysis showed that differences in feeding rates accounted for most of the variability in the data. It also suggested that body size may be important in characterizing the different genera. In general, tropical species are smaller and have higher bite rates than subtropical ones. This study extended the validity of Bergmann’s rule, which states that larger species or larger individuals within species occur towards higher latitudes and/or lower temperatures, for an important group of reef fishes. The identification of large-scale, robust ecological patterns in the feeding ecology of pomacentrid fishes may establish a foundation for predicting large-scale changes in reef fish assemblages with expected future changes in global SST. [ABSTRACT FROM AUTHOR]

For organisms with complex life cycles, variation among individuals in traits associated with survival in one life-history stage can strongly affect the performance in subsequent stages with important repercussions on population dynamics. To identify which individual attributes are the most influential in determining patterns of survival in a cohort of reef fish, we compared the characteristics of Pomacentrus amboinensis surviving early juvenile stages on the reef with those of the cohort from which they originated. Individuals were collected at hatching, the end of the planktonic phase, and two, three, four, six and eight weeks post-settlement. Information stored in the otoliths of individual fish revealed strong carry-over effects of larval condition at hatching on juvenile survival, weeks after settlement (i.e. smaller-is-better). Among the traits examined, planktonic growth history was, by far, the most influential and long-lasting trait associated with juvenile persistence in reef habitats. However, otolith increments suggested that larval growth rate may not be maintained during early juvenile life, when selective mortality swiftly reverses its direction. These changes in selective pressure may mediate growth-mortality trade-offs between predation and starvation risks during early juvenile life. Ontogenetic changes in the shape of selectivity may be a mechanism maintaining phenotypic variation in growth rate and size within a population. [ABSTRACT FROM AUTHOR]

Territorial defense by breeders influences access to resources near defended nest sites by intruder species and may have indirect effects on other species within the territory, leading to local patchiness in distribution patterns. The present study demonstrates that adult males of a damselfish, Pomacentrus amboinensis, indirectly facilitate the increased survival of conspecific juveniles through the territorial defense of their nesting site from potential egg predators. Moreover, male territoriality results in a shift in the selectivity of predation on newly settled juveniles. We monitored the fate of pairs of predator-naïve, newly settled P. amboinensis placed inside and outside nesting territories. Individuals within a pair differed in size by ∼1 mm and were tagged for individual identification. Away from male territories larger juveniles had greater survival, while within territories, larger juveniles suffered higher mortality. Behavioral observations indicated that the moonwrasse Thalassoma lunare, a predator of benthic eggs and small fishes, had reduced access to juveniles within male territories, while another predator on small fishes, the dottyback Pseudochromisfuscus, had unobstructed access to male territories. Experimental removal of P. fuscus indicated that the shift in the direction of phenotypic selection on newly settled juveniles was the indirect effect of aggression by. nest-guarding male damselfish, which resulted in differential access to male territories by these two predators of small fishes. Evidence suggests that behavioral interactions between the resident community and intruders will influence patchiness in selective pressures imposed on benthic prey by influencing both the composition of predator types that can access the prey resource and their relative abundance. How this spatial and temporal patchiness in predator pressure interacts with spatial patchiness of recruiting prey will have a major influence on the resulting distribution of juveniles and their phenotypic traits. [ABSTRACT FROM AUTHOR]

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

The ultraviolet (UV) absorbance of the mucus of a Great Barrier Reef damselfish Pomacentrus amboinensis was investigated with regard to ontogeny and time spent in captivity. The UV absorbance of P. amboinensis mucus increased with fish size and decreased with time spent in captivity. The wavelength of maximum absorbance of the mucus did not change with fish size, but shifted towards shorter wavelengths with increasing time spent in captivity. The UV absorbance of the mucus of fish with ‘fin rot’ was compared to that of similar healthy individuals, and a significant decrease in UV absorbance of unhealthy fish mucus was detected; no wavelength shifting occurred. Pomacentrus amboinensis appears to sequester mycosporine-like amino acids from the diet in order to protect epithelial tissues from UV damage, and decreases in UV absorbance in captive fish were probably due to insufficient dietary availability. [ABSTRACT FROM AUTHOR]

Lunar-related spawning periodicity of the brackish damsel Pomacentrus taeniometopon was investigated by changes in gonadosomatic index (GSI) and ovarian histology. During the spawning season, GSI increased toward the week of the first and last quarter moon. Concomitant with increases in GSI, oocytes laden with yolk developed from the new/full moon to the first/last quarter moon. Postovulatory follicles appeared in the ovary around and after the first/last quarter moon. These results suggest that P. taeniometopon is a semilunar spawner and repeats spawnings twice a month with lunar periodicity during the spawning season. When the fish were reared under laboratory conditions without periodicity of tide, the spawning of P. taeniometopon occurred sporadically. It is likely that the fish uses tidal stimuli in the natural habitat to entrain reproductive activities. [ABSTRACT FROM AUTHOR]

Previous exposure to predators influenced the survival immediately after settlement in a coral reef damselfish, Pomacentrus amboinensis. Rapid learning of antipredator behaviour may in part have driven the rapid increase in survival in the days following this critical transition. [ABSTRACT FROM AUTHOR]

A list of the 493 coastal fish species known or reported from the Mauritian island of Rodrigues is presented, based on specimens of 316 species collected during a five-week survey conducted in September and October 2001. In addition to 351 species documented by photographs and specimens collected during this survey, other documented literature records and some undocumented records are included in this list of Rodrigues fishes. Of the 248 newly recorded fish species collected from Rodrigues, nine also represent undescribed (new) fish species. The new species include: Pomacentrus rodriguesensis Allen and Wright, 2003 , a new species of Pempheris , two new species of Enneapterygius (Family Tripterygiidae), new species of the pseudochromid genera Chlidichthys and Anisochromis , and new species of the gobiid genera Eviota , Cabillus and Calamiana . During the survey, we noticed that in many areas of the lagoon, the substrate and reefs were covered with a thick layer of silt, and this appeared to have a marked effect on the fish diversity and amount of material collected at rotenone stations in these areas. At sites with little or no silt, more species of fishes were seen; with 71 species collected from a reef at Grand Baie. It was disturbing to note that some coral-reef fish taxa (e.g. Scorpaenidae, Serranidae [Anthiinae] Chaetodontidae, Pomacanthidae, Mullidae and Acanthuridae) were surprisingly uncommon in our lagoon reef collections, compared to collections using similar methods in similar habitats at Mauritius, the Comoros, Seychelles, Madagascar and Chagos. [ABSTRACT FROM AUTHOR]

Latitudinal variation in fitness-related traits has often been attributed to local adaptation to climates. In poikilotherms including fishes, lower temperatures and shorter reproductive seasons at high latitudes would be expected to cause a reduction in annual reproductive output of an individual. Theories of latitudinal compensation predict that organisms at high latitudes should evolve compensatory responses for these climatic effects. Therefore, latitudinal compensation in female reproductive rate (egg production rate), that individuals from high latitudes produce eggs at higher rates than those from lower latitudes, is likely to occur. I tested this hypothesis with a latitudinally widespread reef fish Pomacentrus coelestis that is a multiple batch spawner, from three different localities, from temperate to subtropical waters, within Japan. I used common-environment experiments at three different temperatures to compare reproductive capacity among local populations. In the experiments, average inter-spawning intervals were the shortest and average size-specific clutch weight was the heaviest in fish from the most northern locality across all temperatures, showing clear latitudinal clines. Thus, the northern fish can achieve higher reproductive output per unit time both by shortening inter-spawning intervals and increasing size-specific clutch weight. Additionally, faster egg production rate of the northern fish did not result from increased food consumption. This finding suggests that gross egg production efficiency was higher in the northern fish and that northern fish had a superior capacity for reproduction within a season. These results support the prediction that latitudinal compensation occurs in the female reproductive rate of P. coelestis. As the reproductive season of this species decreases drastically with increasing latitude, the observed cline in the reproductive rate must be an adaptive response to the local selective regime, i.e., length of the reproductive season. Such latitudinal compensation in female reproductive rates may be a common pattern in latitudinally widespread fishes. [ABSTRACT FROM AUTHOR]