Action cameras: Bringing aquatic and fisheries research into view

Digital action cameras (ACs) are increasingly being utilized for aquatic research purposes due to their cost effectiveness, versatility, high-resolution imagery, and durability. Here we review the advantages of AC technology in research, with particular emphases on (a) research videography (both in the field and the laboratory), (b) animal-borne studies, and (c) outreach and education purposes. We also review some of the limitations of this technology as represented by environmental factors (e.g., depth, turbidity) and deployment considerations (e.g., lens choices, imaging settings, battery life). As AC technologies evolve in response to growing public interest in their application versatility, researchers are indirectly reaping the rewards, with technological advances that are innovative, cost-effective, and can withstand frequent use in dynamic and rugged field conditions. With such a diversity of options available, future usefulness of ACs in research will only be limited by the creativity of the scientists using them

Stable isotopes and foraging behaviors support the role of antipredator benefits in driving the association between two marine fishes

Research from terrestrial communities shows that diminished predation risk is a principal driver of heterospecific grouping behavior, with foraging ecology predicting the roles that species play in groups, as more vulnerable foragers preferentially join more vigilant ones from whom they can benefit. Meanwhile, field studies examining the adaptive significance of heterospecific shoaling among marine fish have focused disproportionately on feeding advantages such as scrounging or prey-flushing. Juvenile bonefish (Albula vulpes) occur almost exclusively among mojarras (Eucinostomus spp.) and even elect to join them over conspecifics, suggesting they benefit from doing so. We evaluated the roles of risk-related and food-related factors in motivating this pattern of affiliation, estimating: (1) the relative levels of risk associated with each species' search and prey capture activities, via behavioral vulnerability traits discerned from in situ video of heterospecific shoals, and (2) resource use redundancy, using stable isotopes (δ13C, δ15N, and δ34S) to quantify niche overlap. Across four distinct metrics, bonefish behaviors implied a markedly greater level of risk than those of mojarras, typified by higher activity levels and a reduced capacity for overt vigilance; consistent with expectations if their association conformed to patterns of joining observed in terrestrial habitats. Resource use overlap inferred from stable isotopes was low, indicating that the two species partitioned resources and making it unlikely that bonefish derived substantive food-related benefits. Collectively, these findings suggest that the attraction of juvenile bonefish to mojarras is motivated primarily by antipredator advantages, which may include the exploitation of risk-related social cues

Individual differences in activity and habitat selection of juvenile queen conch evaluated using acceleration biologgers

Fine-scale differences in behaviour and habitat use have important ecological implications, but have rarely been examined in marine gastropods. We used tri-axial accelerometer loggers to estimate activity levels and movement patterns of the juvenile queen conch Lobatus gigas (n = 11) in 2 habitat types in Eleuthera, The Bahamas. In 2 manipulations in nearshore areas, queen conchs were equipped with accelerometers and released in adjacent coral rubble or seagrass habitats. Queen conchs were located approximately every 6 h during daylight by snorkeling, to measure individual differences in linear distance moved, and after 24 h they were relocated to an alternate habitat (24 h in each habitat). We found significant inter-individual variability in activity levels, but more consistent levels of activity between the 2 habitat types within individual queen conchs. Four (36%) of the individuals placed in seagrass moved back to the adjacent coral rubble habitat, suggesting selectivity for coral rubble. Individuals showed variable behavioural responses when relocated to the less preferable seagrass habitat, which may be related to differing stress-coping styles. Our results suggest that behavioural variability between individuals may be an important factor driving movement and habitat use in queen conch and, potentially, their susceptibility to human stressors. This study provides evidence of diverse behavioural (activity) patterns and habitat selectivity in a marine gastropod and highlights the utility of accelero meter biologgers for continuously monitoring animal behaviour in the wild

Does coastal light pollution alter the nocturnal behavior and blood physiology of juvenile bonefsh (Albula vulpes)?

Light pollution is a prevalent, but often overlooked, ecological concern in a variety of ecosystems. Marine environments are subjected to artifcial lighting from coastal development, in addition to ofshore sources, such as fshing vessels, oil platforms and cruise ships. Fish species that rely on nearshore habitats are most signifcantly impacted by coastal light pollution, as they are often limited to nearshore habitats due to predation risk in deeper ofshore waters, particularly as juveniles. Juvenile bonefsh [Albula vulpes (Linnaeus, 1758)] inhabit the nearshore environment, and are therefore exposed to coastal lighting and other watershed development impacts. Here, we assessed juvenile bonefsh behavior and physiology in the presence of two common light sources: constant street lighting (high pressure sodium) and intermittent car headlights (H4 halogen). Te behavioral responses were compared with a night and day control, whereas physiology was compared only with a night control. Each behavioral trial had two time periods: light and recovery (2 hrs each). Physiology (blood glucose and whole body cortisol) was assessed after an overnight 8-hr exposure. Te results suggest that there is no effect of light pollution on the swimming behavior or whole body cortisol of juvenile bonefsh, but that both forms of light pollution resulted in elevated blood glucose concentrations (a simple stress indicator) relative to controls, with constant light glucose levels being signifcantly higher. Further research is needed to understand the ecological consequences of light pollution on bonefsh and other coastal marine fsh using additional endpoints, assessing fsh over longer time periods, and ideally combining data from the laboratory and the feld