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Philip L. Munday - One of the best experts on this subject based on the ideXlab platform.

  • The epigenetic landscape of transgenerational acclimation to ocean warming
    Nature Climate Change, 2018
    Co-Authors: Taewoo Ryu, Philip L. Munday, Jennifer M. Donelson, Heather D. Veilleux, Timothy Ravasi
    Abstract:

    Epigenetic inheritance is a potential mechanism by which the environment in one generation can influence the performance of future generations1. Rapid climate change threatens the survival of many organisms; however, recent studies show that some species can adjust to climate-related stress when both parents and their offspring experience the same environmental change2,3. Whether such transgenerational acclimation could have an epigenetic basis is unknown. Here, by sequencing the liver genome, methylomes and transcriptomes of the coral reef fish, Acanthochromis polyacanthus, exposed to current day (+0 °C) or future ocean temperatures (+3 °C) for one generation, two generations and incrementally across generations, we identified 2,467 differentially methylated regions (DMRs) and 1,870 associated genes that respond to higher temperatures within and between generations. Of these genes, 193 were significantly correlated to the transgenerationally acclimating phenotypic trait, aerobic scope, with functions in insulin response, energy homeostasis, mitochondrial activity, oxygen consumption and angiogenesis. These genes may therefore play a key role in restoring performance across generations in fish exposed to increased temperatures associated with climate change. Our study is the first to demonstrate a possible association between DNA methylation and transgenerational acclimation to climate change in a vertebrate. Transgenerational acclimation to warmer oceans has been seen for some marine species. This study shows that the coral reef fish has 193 genes correlated to such acclimation traits, suggesting an epigenetic basis of acclimation.

  • Diel CO_2 cycles do not modify juvenile growth, survival and otolith development in two coral reef fish under ocean acidification
    Marine Biology, 2018
    Co-Authors: Michael D. Jarrold, Philip L. Munday
    Abstract:

    Recent studies show that daily variation in p CO_2 levels can modify the life-history and calcification responses of marine organisms to ocean acidification. The early life stages of coral reef fish exhibit varied growth, survival and otolith development responses to elevated p CO_2, yet no studies to date have considered the substantial diel p CO_2 cycles that occur in shallow reef habitats. Here, we reared three clutches of juvenile Acanthochromis polyacanthus and Amphiprion percula under control (500 µatm), stable, elevated (1000 µatm) and diel cycling, elevated (1000 ± 300 and 1000 ± 500 µatm) p CO_2 for 11 and 6 weeks, respectively. Survival was unaffected by exposure to either elevated stable or diel cycling p CO_2 conditions in both species. For A. polyacanthus there was a non-significant trend of decreased standard length and wet weight under stable, elevated p CO_2 conditions, whereas values in both the diel cycling treatments were closer to those observed under control conditions. A similar non-significant trend was observed for Am. percula , except that exposure to stable, elevated p CO_2 conditions resulted in slightly longer and heavier fish. Finally, otolith size, shape and symmetry in both species were unaffected by exposure to either elevated stable or diel cycling p CO_2 conditions. Overall, our results suggest that the growth, survival and otolith development of juvenile coral reef fishes under ocean acidification is unlikely to be affected, in isolation, by diel cycles in p CO_2.

  • Diel CO2 cycles reduce severity of behavioural abnormalities in coral reef fish under ocean acidification.
    Scientific reports, 2017
    Co-Authors: Michael D. Jarrold, Mark I Mccormick, Craig Humphrey, Philip L. Munday
    Abstract:

    Elevated CO2 levels associated with ocean acidification (OA) have been shown to alter behavioural responses in coral reef fishes. However, all studies to date have used stable pCO2 treatments, not considering the substantial diel pCO2 variation that occurs in shallow reef habitats. Here, we reared juvenile damselfish, Acanthochromis polyacanthus, and clownfish, Amphiprion percula, at stable and diel cycling pCO2 treatments in two experiments. As expected, absolute lateralization of A. polyacanthus and response to predator cue of Am. percula were negatively affected in fish reared at stable, elevated pCO2 in both experiments. However, diel pCO2 fluctuations reduced the negative effects of OA on behaviour. Importantly, in experiment two, behavioural abnormalities that were present in fish reared at stable 750 µatm CO2 were largely absent in fish reared at 750 ± 300 µatm CO2. Overall, we show that diel pCO2 cycles can substantially reduce the severity of behavioural abnormalities caused by elevated CO2. Thus, past studies may have over-estimated the impacts of OA on the behavioural performance of coral reef fishes. Furthermore, our results suggest that diel pCO2 cycles will delay the onset of behavioural abnormalities in natural populations.

  • Responses of neurogenesis and neuroplasticity related genes to elevated CO2 levels in the brain of three teleost species
    Biology Letters, 2017
    Co-Authors: Floriana Lai, Cathrine E. Fagernes, Nicholas J. Bernier, Gabrielle M. Miller, Philip L. Munday, Fredrik Jutfelt, Göran E. Nilsson
    Abstract:

    The continuous increase of anthropogenic CO 2 in the atmosphere resulting in ocean acidification has been reported to affect brain function in some fishes. During adulthood, cell proliferation is fundamental for fish brain growth and for it to adapt in response to external stimuli, such as environmental changes. Here we report the first expression study of genes regulating neurogenesis and neuroplasticity in brains of three-spined stickleback ( Gasterosteus aculeatus ), cinnamon anemonefish ( Amphiprion melanopus ) and spiny damselfish ( Acanthochromis polyacanthus ) exposed to elevated CO 2 . The mRNA expression levels of the neurogenic differentiation factor (NeuroD) and doublecortin (DCX) were upregulated in three-spined stickleback exposed to high-CO 2 compared with controls, while no changes were detected in the other species. The mRNA expression levels of the proliferating cell nuclear antigen (PCNA) and the brain-derived neurotrophic factor (BDNF) remained unaffected in the high-CO 2 exposed groups compared to the control in all three species. These results indicate a species-specific regulation of genes involved in neurogenesis in response to elevated ambient CO 2 levels. The higher expression of NeuroD and DCX mRNA transcripts in the brain of high-CO 2 –exposed three-spined stickleback, together with the lack of effects on mRNA levels in cinnamon anemonefish and spiny damselfish, indicate differences in coping mechanisms among fish in response to the predicted-future CO 2 level.

  • Supplementary material from "Responses of neurogenesis and neuroplasticity related genes to elevated CO 2 levels in the brain of three teleost species"
    2017
    Co-Authors: Floriana Lai, Cathrine E. Fagernes, Nicholas J. Bernier, Gabrielle M. Miller, Philip L. Munday, Fredrik Jutfelt, Göran E. Nilsson
    Abstract:

    The continuous increase of anthropogenic CO 2 in the atmosphere resulting in ocean acidification has been reported to affect brain function in some fishes. During adulthood, cell proliferation is fundamental for fish brain growth and for it to adapt in response to external stimuli, such as environmental changes. Here we report the first expression study of genes regulating neurogenesis and neuroplasticity in brains of three-spined stickleback ( Gasterosteus aculeatus ), cinnamon anemonefish ( Amphiprion melanopus ) and spiny damselfish ( Acanthochromis polyacanthus ) exposed to elevated CO 2 . The mRNA expression levels of the neurogenic differentiation factor (NeuroD) and doublecortin (DCX) were upregulated in three-spined stickleback exposed to high-CO 2 compared with controls, while no changes were detected in the other species. The mRNA expression levels of the proliferating cell nuclear antigen (PCNA) and the brain-derived neurotrophic factor (BDNF) remained unaffected in the high-CO 2 exposed groups compared to the control in all three species. These results indicate a species-specific regulation of genes involved in neurogenesis in response to elevated ambient CO 2 levels. The higher expression of NeuroD and DCX mRNA transcripts in the brain of high-CO 2 –exposed three-spined stickleback, together with the lack of effects on mRNA levels in cinnamon anemonefish and spiny damselfish, indicate differences in coping mechanisms among fish in response to the predicted-future CO 2 level.

Jennifer M. Donelson - One of the best experts on this subject based on the ideXlab platform.

  • The epigenetic landscape of transgenerational acclimation to ocean warming
    Nature Climate Change, 2018
    Co-Authors: Taewoo Ryu, Philip L. Munday, Jennifer M. Donelson, Heather D. Veilleux, Timothy Ravasi
    Abstract:

    Epigenetic inheritance is a potential mechanism by which the environment in one generation can influence the performance of future generations1. Rapid climate change threatens the survival of many organisms; however, recent studies show that some species can adjust to climate-related stress when both parents and their offspring experience the same environmental change2,3. Whether such transgenerational acclimation could have an epigenetic basis is unknown. Here, by sequencing the liver genome, methylomes and transcriptomes of the coral reef fish, Acanthochromis polyacanthus, exposed to current day (+0 °C) or future ocean temperatures (+3 °C) for one generation, two generations and incrementally across generations, we identified 2,467 differentially methylated regions (DMRs) and 1,870 associated genes that respond to higher temperatures within and between generations. Of these genes, 193 were significantly correlated to the transgenerationally acclimating phenotypic trait, aerobic scope, with functions in insulin response, energy homeostasis, mitochondrial activity, oxygen consumption and angiogenesis. These genes may therefore play a key role in restoring performance across generations in fish exposed to increased temperatures associated with climate change. Our study is the first to demonstrate a possible association between DNA methylation and transgenerational acclimation to climate change in a vertebrate. Transgenerational acclimation to warmer oceans has been seen for some marine species. This study shows that the coral reef fish has 193 genes correlated to such acclimation traits, suggesting an epigenetic basis of acclimation.

  • Thermosensitive period of sex determination in the coral-reef damselfish Acanthochromis polyacanthus and the implications of projected ocean warming
    Coral Reefs, 2016
    Co-Authors: G. G. Rodgers, Jennifer M. Donelson, Philip L. Munday
    Abstract:

    Higher temperatures associated with climate change have the potential to significantly alter the population sex ratio of species with temperature-dependent sex determination. Whether or not elevated temperature affects sex determination depends on both the absolute temperature experienced and the stage of development at which the thermal conditions occur. We explored the importance of exposure timing during early development in the coral reef fish, Acanthochromis polyacanthus, by increasing water temperature 1.5 or 3 °C above the summer average (28.5 °C) at different stages of development. We also measured the effect of treatment temperature on fish size and condition, in order to gauge how the thermal threshold for sex-ratio bias may compare with other commonly considered physiological metrics. Increasing grow-out temperature from 28.5 to 30 °C had no effect on the sex ratio of offspring, whereas an increase to 31.5 °C (+3 °C) produced a strong male bias (average ~90%). The thermosensitive period for this species lasted between 25 and 60 d post hatching, with the bias in sex ratio greater the earlier that fish experienced warm conditions. Temperatures high enough to bias the sex ratio are likely to be seen first during late summer (January and February) and would affect clutches produced late in the breeding season. There was no change to fish condition in response to temperature; however, the two higher temperature treatments produced significantly smaller fish at sampling. Clutches produced early in the season could buffer the population from a skewed sex ratio, as their development will remain below the thermal threshold; however, continued ocean warming could mean that clutches produced earlier in the breeding season would also be affected in the longer term. A skewed sex ratio could be detrimental to population viability by reducing the number of females in the breeding population.

  • Transgenerational plasticity of reproduction depends on rate of warming across generations
    Evolutionary applications, 2016
    Co-Authors: Jennifer M. Donelson, David J. Booth, Marian Y. L. Wong, Philip L. Munday
    Abstract:

    Predicting the impacts of climate change to biological systems requires an understanding of the ability for species to acclimate to the projected environmental change through phenotypic plasticity. Determining the effects of higher temperatures on individual performance is made more complex by the potential for environmental conditions experienced in previous and current generations to independently affect phenotypic responses to high temperatures. We used a model coral reef fish (Acanthochromis polyacanthus) to investigate the influence of thermal conditions experienced by two generations on reproductive output and the quality of offspring produced by adults. We found that more gradual warming over two generations, +1.5°C in the first generation and then +3.0°C in the second generation, resulted in greater plasticity of reproductive attributes, compared to fish that experienced the same increase in one generation. Reproduction ceased at the projected future summer temperature (31.5°C) when fish experienced +3.0°C for two generations. Additionally, we found that transgenerational plasticity to +1.5°C induced full restoration of thermally affected reproductive and offspring attributes, which was not possible with developmental plasticity alone. Our results suggest that transgenerational effects differ depending on the absolute thermal change and in which life stage the thermal change is experienced.

  • Thermal sensitivity does not determine acclimation capacity for a tropical reef fish
    The Journal of animal ecology, 2012
    Co-Authors: Jennifer M. Donelson, Philip L. Munday
    Abstract:

    1. Short-term measures of metabolic responses to warmer environments are expected to indicate the sensitivity of species to regional warming. However, given time, species may be able to acclimate to increasing temperature. Thus, it is useful to determine if short-term responses provide a good predictor for long-term acclimation ability. 2. The tropical reef fish Acanthochromis polyacanthus was used to test whether the ability for developmental thermal acclimation of two populations was indicated by their short-term metabolic response to temperature. 3. While both populations exhibited similar short-term responses of resting metabolic rate (RMR) to temperature, fish from the higher-latitude population were able to fully acclimate RMR, while the lower-latitude population could only partially compensate RMR at the warmest temperature. These differences in acclimation ability are most likely due to genetic differences between the populations rather than differences in thermal regimes. 4. This research indicates that acclimation ability may vary greatly between populations and that understanding such variation will be critical for predicting the impacts of warming environmental temperatures. Moreover, the thermal metabolic reaction norm does not appear to be a good predictor of long-term acclimation ability.

  • acclimation to predicted ocean warming through developmental plasticity in a tropical reef fish
    Global Change Biology, 2011
    Co-Authors: Mark I Mccormick, Philip L. Munday, Jennifer M. Donelson, Göran E. Nilsson
    Abstract:

    Determining the capacity of organisms to acclimate and adapt to increased temperatures is key to understand how populations and communities will respond to global warming. Although there is evidence that elevated water temperature affects metabolism, growth and condition of tropical marine fish, it is unknown whether they have the potential to acclimate, given adequate time. We reared the tropical reef fish Acanthochromis polyacanthus through its entire life cycle at present day and elevated (11.5 and13.0 1C) water temperatures to test its ability to thermally acclimate to ocean temperatures predicted to occur over the next 50–100 years. Fish reared at 3.0 1C greater than the present day average reduced their resting oxygen consumption (RMR) during summer compared with fish reared at present day temperatures and tested at the elevated temperature. The reduction in RMR of up to 69mgO2 kg1 h1 in acclimated fish could represent a significant benefit to daily energy expenditure. In contrast, there was no acclimation to summer temperatures exhibited by fish reared at 1.5 1C above present day temperatures. Fish acclimated to 13.0 1C were smaller and in poorer condition than fish reared at present day temperatures, suggesting that even with acclimation there will be significant consequences for future populations of tropical fishes caused by global warming.

Michael J. Kingsford - One of the best experts on this subject based on the ideXlab platform.

  • Latitudinal and Cross-Shelf Patterns of Size, Age, Growth, and Mortality of a Tropical Damselfish Acanthochromis polyacanthus on the Great Barrier Reef
    Diversity, 2019
    Co-Authors: Michael J. Kingsford, David Welch, M. D. O’callaghan
    Abstract:

    Patterns of age and growth of a sedentary damsel fish Acanthochromis polyacanthus were tested over a latitudinal range of approximately 10 degrees (1200 km) on the Great Barrier Reef (GBR), Australia. Within latitudes, these patterns were also compared on reefs in distance strata (inner, mid, and outer) across a continental shelf that ranged in width from 52 to 128 km. Although variation in length-max (SLMAX), growth, age-max (AMAX), and the von Bertalanffy metrics of Linf and K were found within and among latitudes, the greatest variation in some demographic characteristics was found among distance strata across the shelf regardless of latitude. Fish were always relatively smaller at inner shelf reefs and grew more slowly when compared to mid and outer shelf reefs; this was true regardless of the color morph of fish. The oldest fish collected was 11 years old, and there was no consistent variation in age-max among distances from shore. On outer reefs, there was a negative linear relationship with age-max and latitude. This “tropical gradient” of age only explained 34% of the variation; furthermore, this was not found when only the oldest group of fish was considered (top 10%). Fish only reached an age-max of six years on the southernmost reefs. There was a trend for a smaller Linf with latitude but it was not significant and Linf did not vary predictably with water temperature. The sampling of marine protected areas (MPAs) and fished zones did not confound the resultant patterns in that fish were not consistently larger or older in MPAs or fished zones. Instantaneous mortality rates were 0.245–0.685; they were highest at inner reefs and also showed no consistent MPA-related patterns. Our study suggested that the mid and outer shelf waters of the GBR appeared best suited for growth of A. polyacanthus. In conclusion, the position on continental shelves dominated other geographical patterns and needs to be considered in spatial models of growth. We suggest that local environmental conditions such as turbidity and the quality and quantity of plankton likely have a strong influence on distance across the shelf-based demographic patterns of planktivores.

  • interactive effects of ontogeny food ration and temperature on elemental incorporation in otoliths of a coral reef fish
    Environmental Biology of Fishes, 2010
    Co-Authors: Michael J. Kingsford, Benjamin D Walther, M D Ocallaghan, Malcolm T Mcculloch
    Abstract:

    The potential for environmental and physiological modification of elemental incorporation in otoliths is significant and must be validated before otoliths can be used reliably to estimate water parameters over the life history of a fish. We experimentally manipulated temperature and diet quantity for juvenile, sub-adult, and adult Acanthochromis polyacanthus, a tropical damselfish of the SW Pacific. Significant interactive effects between life history stage, temperature and food quantity were observed for otolith Ba/Ca, while significant interactions between stage and food were observed for Sr/Ca. Specific growth rates were negatively correlated with DBa and DSr for juveniles and sub-adults. These interactions indicated elemental incorporation dynamics varied depending on the life history stage, suggesting variation in effects of stage-specific metabolism or reproductive status. Our results highlight complex responses of elemental incorporation to both endogenous and exogenous factors. Interpretations of life history transects across otoliths must account for these effects to avoid confounding environmental variability with ontogenetic changes in physiology.

  • Otolith chemistry of the non-dispersing reef fish Acanthochromis polyacanthus: cross-shelf patterns from the central Great Barrier Reef
    Marine Ecology Progress Series, 2009
    Co-Authors: Michael J. Kingsford, J. M. Hughes, Heather M. Patterson
    Abstract:

    The influence of cross-shelf gradients, within and among distance strata, on the otolith chemistry of the non-dispersing reef fish Acanthochromis polyacanthus was examined on the Great Barrier Reef. Most of the variation in elemental ratios (Mg/Ca, Cu/Ca, Sr/Ca, Ba/Ca) was at the level of sites within reefs; some broad patterns of otolith chemistry were found cross-shelf. Sr/Ca and Ba/Ca ratios increased with distance from shore. Highest ratios of Mn/Ca and Cu/Ca were found at the outermost shelf sites at Myrmidon Reef, but Mn levels were generally greatest within 45 km of shore. Elevated ratios of Ba/Ca at Myrmidon Reef were persistent over 3 yr and are likely indicative of upwelling, which is known to occur in the area. The Ba/Ca ratios were the highest ever reported in marine fish otoliths, and accuracy of our estimates was confirmed in a paired laboratory test. The robustness of reef-wide chemical signatures in fish was weak, but unique signatures were found within reefs. High resolution elemental records could help to identify sites affected by upwelling and the periodicity of upwelling events.

  • dispersal in the spiny damselfish Acanthochromis polyacanthus a coral reef fish species without a larval pelagic stage
    Molecular Ecology, 2008
    Co-Authors: Vanessa C Millersims, Gabriele Gerlach, Michael J. Kingsford, Jelle Atema
    Abstract:

    The spiny damselfish, Acanthochromis polyacanthus, is widely distributed throughout the Indo-Australian archipelago. However, this species lacks a larval dispersal stage and shows genetic differentiation between populations from closely spaced reefs. To investigate the dispersal strategy of this unique species, we used microsatellite markers to determine genetic relatedness at five dispersal scales: within broods of juveniles, between adults within a collection site (~30 m2), between sites on single reefs, between nearby reefs in a reef cluster, and between reef clusters. We sampled broods of juveniles and adults from seven reefs in the Capricorn-Bunker and Swain groups of the Great Barrier Reef. We found that extra-pair mating is rare and juveniles remain with their parents until fledged. Adults from single sites are less related than broods but more related than expected by chance. However, there is no evidence of inbreeding suggesting the existence of assortative mating and/or adult migration. Genetic differences were found between all of the reefs tested except between Heron and Sykes reefs, which are separated only by a 2-km area of shallow water (less than 10 m). There was a strong correlation between genetic distance, geographical distance and water depth. Apparently, under present-day conditions spiny damselfish populations are connected only between sites of shallow water, through dispersal of adults over short distances. Assuming that dispersal behaviour has not changed, the broad distribution of A. polyacanthus as a species is likely based on historical colonization patterns when reefs were connected by shallow water at times of lower sea levels.

  • Elevated temperature restricts growth potential of the coral reef fish Acanthochromis polyacanthus
    Coral Reefs, 2008
    Co-Authors: Philip L. Munday, Michael J. Kingsford, M. D. O’callaghan, Jennifer M. Donelson
    Abstract:

    In order to test the effect of temperature variation on the growth of a common coral-reef fish, Acanthochromis polyacanthus, juveniles, sub-adults and adults were reared on either high or low food rations at temperatures corresponding to the long-term (14 year) minimum, average and maximum summer sea-surface temperatures (26, 28 and 31°C respectively) at Orpheus Island, Great Barrier Reef, Australia. Both temperature and food supply affected the growth of juvenile and adult A. polyacanthus. Individuals grew more on high food rations, but growth declined with increasing temperature. Importantly, at 31°C, the growth of juveniles and adults on the high food ration was nearly identical to growth on the low food ration. This indicates that the capacity for growth is severely limited at higher ocean temperatures that are predicted to become the average for Orpheus Island within the next 100 years as a result of rapid climate change.

Mark I Mccormick - One of the best experts on this subject based on the ideXlab platform.

  • Parents know best: transgenerational predator recognition through parental effects.
    PeerJ, 2020
    Co-Authors: Jennifer Ann Atherton, Mark I Mccormick
    Abstract:

    In highly biodiverse systems, such as coral reefs, prey species are faced with predatory threats from numerous species. Recognition of predators can be innate, or learned, and can help increase the chance of survival. Research suggests that parental exposure to increased predatory threats can affect the development, behaviour, and ultimately, success of their offspring. Breeding pairs of damselfish (Acanthochromis polyacanthus) were subjected to one of three olfactory and visual treatments (predator, herbivore, or control), and their developing embryos were subsequently exposed to five different chemosensory cues. Offspring of parents assigned to the predator treatment exhibited a mean increase in heart rate two times greater than that of offspring from parents in herbivore or control treatments. This increased reaction to a parentally known predator odour suggests that predator-treated parents passed down relevant threat information to their offspring, via parental effects. This is the first time transgenerational recognition of a specific predator has been confirmed in any species. This phenomenon could influence predator-induced mortality rates and enable populations to adaptively respond to fluctuations in predator composition and environmental changes.

  • Impacts of increased ocean temperatures on a low-latitude coral reef fish – Processes related to oxygen uptake and delivery
    Journal of thermal biology, 2018
    Co-Authors: G. G. Rodgers, Jodie L. Rummer, Linda K. Johnson, Mark I Mccormick
    Abstract:

    Abstract Increasing temperatures are expected to significantly affect the physiological performance of ectotherms, particularly in tropical locations. The shape of an organism's thermal reaction norm can provide important information on its capacity to persist under climate change scenarios; however, difficulty lies in choosing a measurable trait that best depicts physiological performance. This study investigated the effects of elevated temperatures on processes related to oxygen uptake and delivery, including oxygen consumption, haematology, and tissue health for a low-latitude population of coral reef damselfish. Acanthochromis polyacanthus were collected from the Torres Strait (10°31–46′S, 142°20–35′E) and maintained at current average ocean temperatures (+0 °C; seasonally cycling), + 1.5 °C and + 3 °C higher than present day temperatures for 10 months. Aerobic performance indicated a limit to metabolic function at + 3 °C (33 °C), following an increase in aerobic capacity at + 1.5 °C (31.5 °C). Neither haematological parameters nor gill morphology showed the same improvement in performance at + 1.5 °C. Gill histopathology provided the first indicator of a decline in organism health, which corresponded with mortality observations from previous research. Findings from this study suggest thermal specialisation in this low-latitude population as well as variation in thermal sensitivity, depending on the physiological trait.

  • Juvenile coral reef fish alter escape responses when exposed to changes in background and acute risk levels
    Animal Behaviour, 2017
    Co-Authors: Ryan A. Ramasamy, Bridie J. M. Allan, Mark I Mccormick, Matthew D Mitchell, Douglas P. Chivers, Maud C. O. Ferrari
    Abstract:

    The response of prey to predation threats is often plastic and can vary with the individual's perceived level of threat. To determine whether prey escape responses can be modulated by background levels of risk or short-term acute risk, we maintained juvenile damselfish, Acanthochromis polyacanthus, under high- or low-risk background conditions for several days and then exposed them to an acute risk (high-risk alarm cues or a low-risk saltwater control) minutes prior to startling them with a mechanical disturbance. Fish responded in one of two ways: they either made a C-start escape response or backed away from the threat. While exposure to either background high risk or acute high risk increased the proportion of C-starters, surprisingly the frequency of C-starters decreased when background high risk and acute risk types were combined. Exposure to an acute high-risk cue increased the escape performance for both types of escape responses. However, when the acute high-risk cue occurred within high-risk background conditions, this only increased the performance of C-start escape responses. Non-C-starters reacted similarly in both background risk conditions. Background risk and acute risk acted in a simple additive manner, as seen by the lack of interaction between the two factors. Results showed that escape responses are amplified as the level of perceived risk increases.

  • Diel CO2 cycles reduce severity of behavioural abnormalities in coral reef fish under ocean acidification.
    Scientific reports, 2017
    Co-Authors: Michael D. Jarrold, Mark I Mccormick, Craig Humphrey, Philip L. Munday
    Abstract:

    Elevated CO2 levels associated with ocean acidification (OA) have been shown to alter behavioural responses in coral reef fishes. However, all studies to date have used stable pCO2 treatments, not considering the substantial diel pCO2 variation that occurs in shallow reef habitats. Here, we reared juvenile damselfish, Acanthochromis polyacanthus, and clownfish, Amphiprion percula, at stable and diel cycling pCO2 treatments in two experiments. As expected, absolute lateralization of A. polyacanthus and response to predator cue of Am. percula were negatively affected in fish reared at stable, elevated pCO2 in both experiments. However, diel pCO2 fluctuations reduced the negative effects of OA on behaviour. Importantly, in experiment two, behavioural abnormalities that were present in fish reared at stable 750 µatm CO2 were largely absent in fish reared at 750 ± 300 µatm CO2. Overall, we show that diel pCO2 cycles can substantially reduce the severity of behavioural abnormalities caused by elevated CO2. Thus, past studies may have over-estimated the impacts of OA on the behavioural performance of coral reef fishes. Furthermore, our results suggest that diel pCO2 cycles will delay the onset of behavioural abnormalities in natural populations.

  • Kin recognition in embryonic damselfishes
    Oikos, 2017
    Co-Authors: Jennifer Ann Atherton, Mark I Mccormick
    Abstract:

    Predator-induced mortality rates are highest in early life stages; therefore, early recognition of threats can greatly increase survival chances. Some species of coral reef fishes have been frequently found to recruit back to their natal reefs; in this instance, there is a high chance of juveniles encountering their siblings, among other kin, after hatching. Kin recognition plays an important ecological role in that it allows individuals to protect genetically similar relatives, and hence increase their inclusive fitness. By observing changes in heart rates, we demonstrated that embryos of two damselfish species, Acanthochromis polyacanthus and Amphiprion melanopus, not only possess recognition of kin and damage-released alarm odours, but also react to them in a graded manner. Such refined olfactory capabilities in embryonic stage organisms (seven and eleven days after fertilisation) suggest identification of threats may provide survival advantages post-hatching, such as the informed choice of low risk habitats at settlement. To our knowledge this is the first time that kin recognition has been identified in embryos of any species.

Sandra A Binning - One of the best experts on this subject based on the ideXlab platform.

  • Maximum thermal limits of coral reef damselfishes are size dependent and resilient to near-future ocean acidification.
    The Journal of experimental biology, 2017
    Co-Authors: Timothy D Clark, Dominique G Roche, Sandra A Binning, Ben Speers-roesch, Josefin Sundin
    Abstract:

    Theoretical models predict that ocean acidification, caused by increased dissolved CO2, will reduce the maximum thermal limits of fishes, thereby increasing their vulnerability to rising ocean temperatures and transient heatwaves. Here, we tested this prediction in three species of damselfishes on the Great Barrier Reef, Australia. Maximum thermal limits were quantified using critical thermal maxima (CTmax) tests following acclimation to either present-day or end-of-century levels of CO2 for coral reef environments (∼500 or ∼1000 µatm, respectively). While species differed significantly in their thermal limits, whereby Dischistodus perspicillatus exhibited greater CTmax (37.88±0.03°C; N=47) than Dascyllus aruanus (37.68±0.02°C; N=85) and Acanthochromis polyacanthus (36.58±0.02°C; N=63), end-of-century CO2 had no effect (D. aruanus) or a slightly positive effect (increase in CTmax of 0.16°C in D. perspicillatus and 0.21°C in A. polyacanthus) on CTmax Contrary to expectations, early-stage juveniles were equally as resilient to CO2 as larger conspecifics, and CTmax was higher at smaller body sizes in two species. These findings suggest that ocean acidification will not impair the maximum thermal limits of reef fishes, and they highlight the critical role of experimental biology in testing predictions of theoretical models forecasting the consequences of environmental change.

  • Maximum thermal limits of coral reef damselfishes are size dependent and resilient to near-future ocean acidification
    The Journal of Experimental Biology, 2017
    Co-Authors: Timothy Clark, Dominique G Roche, Sandra A Binning, Ben Speers-roesch, Josefin Sundin
    Abstract:

    Theoretical models predict that ocean acidification, caused by increased dissolved CO 2 , will reduce the maximum thermal limits of fishes, thereby increasing their vulnerability to rising ocean temperatures and transient heatwaves. Here, we test this prediction in three species of damselfishes on the Great Barrier Reef, Australia. Maximum thermal limits were quantified using critical thermal maxima (CT max ) tests following acclimation to either present-day or end-of-century levels of CO 2 for coral reef environments (∼500 or ∼1,000 µatm, respectively). While species differed significantly in their thermal limits, whereby Dischistodus perspicillatus exhibited greater CT max (37.88±0.03 o C; N=47) than Dascyllus aruanus (37.68±0.02 o C; N=85) and Acanthochromis polyacanthus (36.58±0.02 o C; N=63), end-of-century CO 2 had no effect ( D. aruanus ) or a slightly positive effect (increase in CT max of 0.16 o C in D. perspicillatus and 0.21 o C in A. polyacanthus ) on CT max . Contrary to expectations, smaller individuals were equally as resilient to CO 2 as larger conspecifics, and CT max was higher at smaller body sizes in two species. These findings suggest that ocean acidification will not impair the maximum thermal limits of reef fishes, and they highlight the critical role of experimental biology in testing predictions of theoretical models forecasting the consequences of environmental change.

  • Physiological plasticity to water flow habitat in the damselfish, Acanthochromis polyacanthus: Linking phenotype to performance
    PLoS ONE, 2015
    Co-Authors: Sandra A Binning, David Nusbaumer, Albert F.h. Ros, Dominique G Roche
    Abstract:

    The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physio- logical traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related tomorphological variation among and within species. However, physiological traits related to performance have been less well studied.We experimentally reared juvenile damselfish, Acanthochromis polya- canthus, under different water flow regimes to test 1) whether aspects of swimming physiol- ogy and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to perfor- mance differences observed in wild fish. We found that maximummetabolic 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 swim- ming 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 ex- plain 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 differ- ences in physiology.

  • Localised intraspecific variation in the swimming phenotype of a coral reef fish across different wave exposures
    Oecologia, 2014
    Co-Authors: Sandra A Binning, Dominique G Roche, Christopher J Fulton
    Abstract:

    Wave-driven water flow is a major force structuring marine communities. Species distributions are partly determined by the ability to cope with variation in water flow, such as differences in the assemblage of fish species found in a given water flow environment being linked to swimming ability (based on fin shape and mode of locomotion). It remains unclear, however, whether similar assembly rules apply within a species. Here we show phenotypic variation among sites in traits functionally linked to swimming ability in the damselfish Acanthochromis polyacanthus. These sites differ in wave energy and the observed patterns of phenotypic differences within A. polyacanthus closely mirrored those seen at the interspecific level. Fish from high-exposure sites had more tapered fins and higher maximum metabolic rates than conspecifics from sheltered sites. This translates to a 36% larger aerobic scope and 33% faster critical swimming speed for fish from exposed sites. Our results suggest that functional relationships among swimming phenotypes and water flow not only structure species assemblages, but can also shape patterns of phenotypic divergence within species. Close links between locomotor phenotype and local water flow conditions appear to be important for species distributions as well as phenotypic divergence across environmental gradients.

  • Wave-induced abiotic stress shapes phenotypic diversity in a coral reef fish across a geographical cline
    Coral Reefs, 2013
    Co-Authors: Christopher J Fulton, Sandra A Binning, Peter C. Wainwright, David R. Bellwood
    Abstract:

    While morphological variation across geographical clines has been well documented, it is often unclear whether such changes enhance individual performance to local environments. We examined whether the damselfish Acanthochromis polyacanthus display functional changes in swimming phenotype across a 40-km cline in wave-driven water motion on the Great Barrier Reef, Australia. A. polyacanthus populations displayed strong intraspecific variation in swimming morphology and performance that matched local levels of water motion: individuals on reefs subject to high water motion displayed higher aspect-ratio fins and faster swimming speeds than conspecifics on sheltered reefs. Remarkably, intraspecific variation within A. polyacanthus spanned over half the diversity seen among closely related damselfish species from the same region. We find that local selection driven by wave-induced abiotic stress is an overarching ecological mechanism shaping the inter- and intraspecific locomotor diversity of coral reef fishes.