Biology subjects

Feary, D. A.

Publications and source records attributed to Feary, D. A..

4 recordsLinked to original sources

bioRxiv2023

Downscaling global reference points to assess the sustainability of local fisheries

Multispecies coral reef fisheries are typically managed by local communities who often lack research and monitoring capacity, which prevents estimation of well-defined sustainable reference points to perform locally relevant fishery assessments. Recent global advances in modelling coral reef fisheries have developed pathways to use environmental indicators to estimate multispecies sustainable reference points. These global reference points are a promising tool for assessing data-poor reef fisheries but need to be downscaled to be relevant to resource practitioners. Here, using a small-scale multispecies reef fishery from Papua New Guinea, we estimate sustainable reference points and assess the sustainability of the fishery by integrating global-scale analyses with local-scale environmental conditions, fish catch, reef area, standing biomass estimates, and fishers perceptions. We found that assessment results from global models applied to the local context of our study location provided results consistent with local fishers perceptions. Specifically, our downscaled results suggest that the fishing community is overfishing their reef fish stocks (i.e., catching more than can be sustained) and stocks are below BMMSY (i.e., below biomass levels that maximize production), making the overall reef fishery unsustainable. These results were consistent with fisher perceptions that reef fish stocks were declining in abundance and mean fish length, and that they had to spend more time finding fish. Our downscaled site-level assessment reveals severe local resource exploitation, whose dynamics are masked in national-scale assessments, emphasizing the importance of matching assessments to the scale of management. More broadly, our study shows how global reference points can be applied locally when long-term data are not available, providing baseline assessments for sustainably managing previously un-assessed multispecies reef fisheries around the globe.

ecology↗

bioRxiv2020

Growth impacts in a changing ocean: insights from two coral reef fishes in an extreme environment

Determining the life history consequences for fishes living in extreme and variable environments will be vital in predicting the likely impacts of ongoing climate change on reef fish demography. Here, we compare size-at-age and maximum body size of two common reef fish species (Lutjanus ehrenbergii and Pomacanthus maculosus) between the environmentally extreme Arabian/Persian Gulf (‘Arabian Gulf’) and adjacent comparably benign Oman Sea. Additionally, we use otolith increment width profiles to investigate the influence of temperature, salinity and productivity on the individual growth rates. Individuals of both species showed smaller size-at-age and lower maximum size in the Arabian Gulf compared to conspecifics in the less extreme and less variable environment of the Oman Sea, suggesting a life-history trade-off between size and metabolic demands. Salinity was the best environmental predictor of interannual growth across species and regions, with low growth corresponding to more saline conditions. However, salinity had a weaker negative effect on interannual growth of fishes in the Arabian Gulf than in the Oman Sea, indicating Arabian Gulf populations may be better able to acclimate to changing environmental conditions. Temperature had a weak positive effect on the interannual growth of fishes in the Arabian Gulf, suggesting that these populations may still be living within their thermal windows. Our results highlight the potential importance of osmoregulatory cost in impacting growth, and the need to consider the effect of multiple stressors when investigating the consequences of future climate change on fish demography.Competing Interest StatementThe authors have declared no competing interest.View Full Text

ecology↗

bioRxiv2020

Behavioural traits and feeding ecology of Mediterranean lionfish and native species naivete to lionfish predation

The detrimental effects of invasion by Indo-Pacific lionfish (Pterois volitans/miles) on western Atlantic fishes have spurred concerns for Mediterranean fish biodiversity, where a Lessepsian invasion of lionfish has recently begun. In order to assess the potential impact on biodiversity, we examine key behavioural and ecological traits of lionfish, and the resident fish community in the Mediterranean, that may contribute to lionfish invasion success. We focus on Cyprus, where lionfish populations were first sighted in 2012 and have now established abundant and stable populations. Using field observations, we examine lionfish predatory behaviour and feeding ecology, and resident fish species naivete to hunting lionfish. Our findings suggest that lionfish in the Mediterranean are crepuscular generalist predators, with prey targeted dominated by small-bodied benthic or bentho-pelagic associated species. Such prey are more likely to be native than introduced (Lessepsian) fishes, with native prey fishes showing greater naivete towards lionfish than Lessepsian prey species. Notably, one of the Mediterraneans key ecological fish species (the native damselfish Chromis chromis), showed the highest level of naivete and was the most heavily targeted prey. Overall, lionfish in the Mediterranean show similar predatory behaviour and ecology to their western Atlantic counterparts. Although the Mediterranean invasion is still relatively recent, it may result in a similar disruption to reef fish biomass to that recorded in the Atlantic, with impact to the structure and biodiversity of reef fish communities and the services they provide.

ecology↗

bioRxiv2019

The influence of thermal extremes on coral reef fish behaviour in the Persian Gulf

Despite increasing environmental variability within marine ecosystems, little is known about how coral reef fish species will cope with future climate scenarios. The Arabian/Persian Gulf is an extreme environment, providing an opportunity to study fish behaviour on reefs with seasonal temperature ranges which include both values above the mortality threshold of Indo-Pacific reef fish, and values below the optimum temperature for growth. Summer temperatures in the Gulf are comparable to those predicted for the tropical ocean by 2090-2099. Using field observations in winter, spring and summer, and laboratory experiments, we examined the foraging activity, distance from refugia and resting time of Pomacentrus trichrourus (pale-tail damselfish). Observations of fish behaviour in natural conditions showed that individuals substantially reduced distance from refugia and feeding rate and increased resting time at sub-optimal environmental temperatures in winter (average SST = 21{degrees}C) and summer (average SST = 34{degrees}C), while showing high movement and feeding activity in spring (average SST= 27{degrees}C). Diet was dominated by plankton in winter and spring, while fish used both plankton and benthic trophic resources in summer. These findings were corroborated under laboratory conditions: in a replicated aquarium experiment, time away from refugia and activity were significantly higher at 28{degrees}C (i.e., spring temperature conditions) compared to 21 {degrees}C (i.e., winter temperature conditions). Our findings suggest that P. trichrourus may have adapted to the Arabian/Persian Gulf environment by downregulating costly activity during winter and summer and upregulating activity and increasing energy stores in spring. Such adaptive behavioural plasticity may be an important factor in the persistence of populations within increasing environmentally variable coral reef ecosystems.

animal behavior and cognition↗