Does coastal light pollution alter the nocturnal behavior and blood physiology of juvenile bonefish (<i>Albula vulpes</i>)?

Abstract

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.