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Group‐living in animals comes with a number of benefits associated with predator avoidance, foraging, and reproduction. A large proportion of fish species display grouping behaviour. Fish may also be particularly vulnerable to climate‐related stressors including thermal variation, hypoxia, and acidification. As climate‐related stressors are expected to increase in magnitude and frequency, any effects on fish behaviour may be increased and affect the ability of fish species to cope with changing conditions. Here we conduct a systematic review of the effects of temperature, hypoxia, and acidification on individual sociability and group cohesion in shoaling and schooling fishes. Searches of the published and grey literature were carried out, and studies were included or excluded based on selection criteria. Data from studies were then included in a meta‐analysis to examine broad patterns of effects of climate‐related stressors in the literature. Evidence was found for a reduction in group cohesion at low oxygen levels, which was stronger in smaller groups. While several studies reported effects of temperature and acidification, there was no consistent effect of either stressor on sociability or cohesion. There was some evidence that marine fishes are more strongly negatively affected by acidification compared with freshwater species, but results are similarly inconsistent and more studies are required. Additional studies of two or more stressors in combination are also needed, although one study found reduced sociability following exposure to acidification and high temperatures. Overall, there is some evidence that hypoxia, and potentially other climate‐related environmental changes, impact sociability and group cohesion in fishes. This may reduce survival and adaptability in shoaling and schooling species and have further ecological implications for aquatic systems. However, this synthesis mainly highlights the need for more empirical studies examining the effects of climate‐related factors on social behaviour in fishes. [ABSTRACT FROM AUTHOR]

The use of different mazes to assess spatial learning has become more common in fish behavior studies in recent decades. This increase in fish cognition research has opened the door to numerous possibilities for exciting and diverse questions, such as identifying ecological drivers of spatial cognition and understanding the role individual variation plays in navigational abilities. There are many different types of mazes, each with its own specific considerations, making it challenging to determine exactly which spatial test is the most relevant and appropriate for a particular experiment. Many spatial mazes, such as the T‐maze and Y‐maze, have been successfully adapted from rodent studies, particularly with respect to zebrafish, a widely accepted non‐mammalian model in biomedical studies. Standardization across studies is increasing with these easily accessible maze designs, validating them for use in fish; however, variations in design (e.g., length of arms and scale) and procedure still exist, and the impact of these variations on results is largely unknown. The efforts to standardize mazes outside zebrafish work are also more limited. Other mazes have been developed specifically for use on fish, with design modifications varying widely, making it difficult to draw comparisons. In this review, we have highlighted the many design and procedural elements that should be considered for the acquisition of reliable behavioral data, with the goal of drawing readers' attention to aspects of experimentation that are often not given the careful consideration that they deserve. We then argue that additional focused research and reporting is needed to produce more reliable methods in spatial learning research across a broader range of subjects. [ABSTRACT FROM AUTHOR]

Sailfin catfish, Pterygoplichthys, is a genus of fish common in the ornamental aquarium trade. Originally from South America, they are now invasive in numerous locations around the globe. We report the first records of Pterygoplichthys in the United Kingdom. We captured one Pterygoplichthys joselimaianus and one Pterygoplichthys pardalis in an artificial side channel of the River Kelvin in Glasgow, Scotland on 30 August 2021 and 6 September 2021, respectively. Further monitoring and public education will be important as river temperatures increase to prevent establishment of these species, which have become invasive in other parts of the world. [ABSTRACT FROM AUTHOR]

While a large body of research has focused on the physiological effects of multiple environmental stressors, how behavioural and life‐history plasticity mediate multiple‐stressor effects remains underexplored. Behavioural plasticity can not only drive organism‐level responses to stressors directly but can also mediate physiological responses. Here, we provide a conceptual framework incorporating four fundamental trade‐offs that explicitly link animal behaviour to life‐history‐based pathways for energy allocation, shaping the impact of multiple stressors on fitness. We first address how small‐scale behavioural changes can either mediate or drive conflicts between the effects of multiple stressors and alternative physiological responses. We then discuss how animal behaviour gives rise to three additional understudied and interrelated trade‐offs: balancing the benefits and risks of obtaining the energy needed to cope with stressors, allocation of energy between life‐history traits and stressor responses, and larger‐scale escape from stressors in space or time via large‐scale movement or dormancy. Finally, we outline how these trade‐offs interactively affect fitness and qualitative ecological outcomes resulting from multiple stressors. Our framework suggests that explicitly considering animal behaviour should enrich our mechanistic understanding of stressor effects, help explain extensive context dependence observed in these effects, and highlight promising avenues for future empirical and theoretical research. [ABSTRACT FROM AUTHOR]

We describe a core idea underlying a modeling approach used by behavioral ecologists to explain variation in animal personalities: that behavior depends in a dynamic, interactive way on the individual's state, social/ecological context and long-term needs. These dynamics are accounted for in state-dependent, stochastic dynamic programming models that aim to explain patterns of behavioral consistency and change over a lifetime, consistent individual differences in personality, and variation in correlations among personality traits. In particular, the approach highlights the importance of negative versus positive state-behavior feedback loops in explaining personality patterns. [ABSTRACT FROM AUTHOR]

Fishing causes direct removal of individuals from wild populations but can also cause a physiological disturbance in fish that are released or discarded after capture. While sublethal physiological effects of fish capture have been well studied in commercial and recreational fisheries, this issue has been overlooked for the ornamental fish trade, where it is common to capture fish from the wild and discard non-target species. We examined metabolic responses to capture and discard procedures in the three-striped dwarf cichlid Apistogramma trifasciata , a popular Amazonian aquarium species that nonetheless may be discarded when not a target species. Individuals ( n  = 34) were tagged and exposed to each of four treatments designed to simulate procedures during the capture and discard process: 1) a non-handling control; 2) netting; 3) netting +30 seconds of air exposure; and 4) netting +60 seconds of air exposure. Metabolic rates were estimated using intermittent-flow respirometry, immediately following each treatment then throughout recovery overnight. Increasing amounts of netting and air exposure caused an acute increase in oxygen uptake and decrease in available aerobic scope. In general, recovery occurred quickly, with rapid decreases in oxygen uptake within the first 30 minutes post-handling. Notably, however, male fish exposed to netting +60 seconds of air exposure showed a delayed response whereby available aerobic scope was constrained <75% of maximum until ~4-6 hours post-stress. Larger fish showed a greater initial increase in oxygen uptake post-stress and slower rates of recovery. The results suggest that in the period following discard, this species may experience a reduced aerobic capacity for additional behavioural/physiological responses including feeding, territory defence and predator avoidance. These results are among the first to examine impacts of discard practises in the ornamental fishery and suggest ecophysiological research can provide valuable insight towards increasing sustainable practises in this global trade., (© The Author(s) 2024. Published by Oxford University Press and the Society for Experimental Biology.)