Virtual reality fish platform offers insights into the impact of artificial light on aquatic life Sadie Harley Scientific Editor Robert Egan Senior Editor A virtual reality (VR) platform has given researchers new insights into how artificial light at night alters the way coral reef fish respond to predators. The study brings together, for the first time, the metabolic expertise of the University of Glasgow with an innovative immersive virtual reality (VR) platform designed at the Institut de Neurosciences de la Timone and implemented at CRIOBE (Center de Recherches Insulaires et Observatoire de l'Environnement). The study, "Artificial light at night suppresses metabolic response of a coral reef fish to a virtual predator," is published in the journal Conservation Physiology.

The researchers used the platform to project interactive VR simulations onto the walls of a specially designed fish tank, providing a tool to investigate and better understand how exposure to artificial light at night may be affecting sea life behavior and physiology under controlled yet ecologically realistic conditions. Artificial light at night is an increasingly widespread form of pollution in coastal environments. Previous studies have shown that it can alter animal behavior, reproduction and survival, but its effects on predator-prey interactions are poorly understood because it is difficult to study these encounters in the wild and not possible to realistically re-create them with large predators in laboratory settings.

Inside the virtual predator test For this study, the research team observed clownfish in the VR aquarium, with realistic 3D underwater scenes projected onto all four walls and the floor of the tank. During each experiment, the clownfish encountered a virtual attack by one of their natural large predators, Heller's barracuda, while researchers simultaneously measured oxygen consumption to assess their metabolic rate. Prior to their time in the virtual reality tank, the clownfish had been split into two groups: one that had previously been exposed to ambient light—natural daylight and nightlight—and a second group that had been exposed to artificial light at night from coastal hotels.

Light history changed the response The researchers found that the fish raised under natural lighting exhibited a strong anti-predator response, characterized by a suppression of their metabolic rate when the projection of the predator seemed to come near them in the tank. In contrast, the fish in the group that had been exposed to artificial light increased their metabolic rate when faced with the same predator stimulus. The ability to lower metabolic rate in the presence of a predator may give small fish, such as clownfish, a life-saving advantage because it allows them to slow their breathing and remain unobserved as they attempt to stay hidden.

Researchers point to wider risks Shaun Killen, professor of ecophysiology at the University of Glasgow and senior author of the study, said, "Our study is the first to demonstrate that artificial light at night can modify how fish respond physiologically during critical interactions with larger predators, making artificial light an important consideration when managing coastal systems.