poster
The light pollution paradox: more fish in less sustainable habitat
Larval recruitment is a key life history trait for fish, conditioning species’ fate at an individual, population and community level. This process has many involvements, from the connectivity of the population, stock replenishment or adult fitness, being very sensitive to environmental change and anthropogenic activities, including light pollution. The global extent of artificial light at night (ALAN) on marine organisms is twofold. In the first place, ALAN is ubiquitous, impacting a quarter of the world’s coastline and pervasive until 10 meters deep for 2.7 % of the world’s exclusive economic zone. In the second place, ALAN is omnipotent, impacting most of the marine taxa examined to date and influencing a wide range of biological and ecological processes. Nevertheless, light pollution remains unstudied for larval recruitment. In the present work, we reproduced environmental light pollution in the wild, in the lagoon of Moorea, French Polynesia, to examine the impact on fish recruitment. We particularly focused on two of the most dominant species of coral reef damselfish: the yellowtail dascyllus (Dascyllus flavicaudus) and the blue-green chromis (Chromis viridis). Using multidisciplinary approach (such as otoliths extraction, nighttime behavioural test or respirometry test), we found out that light pollution increases the recruitment of fish larvae to corals exposed to light pollution, but has also drastic carry over effect on growth, metabolic rate, and survival. In other words, ALAN has the potential to attract organisms to a less suitable environment, generating a peculiar anthropogenic stressor.