Artificial light at night causes reproductive failure in clownfish

The Earth is getting brighter at night, as artificial light at night (ALAN) continues to increase and extend its reach. Despite recent recognition of the damaging impacts of ALAN on terrestrial ecosystems, research on the impacts of ALAN on marine systems is comparatively lacking. To further our understanding of the impacts of ALAN on marine organisms, this study examines the impact of ALAN on the reproductive fitness of the common clownfish Amphiprion ocellaris. We assessed how exposure to low levels of ALAN affects 1) frequency of spawning, 2) egg fertilisation success, and 3) hatching success of A. ocellaris under control (12:12 day-night) and treatment (12:12 day-ALAN) light regimes. While we found exposure to ALAN had no impact on the frequency of spawning or fertilisation success, ALAN had dramatic effects on hatching. Amphiprion ocellaris eggs incubated in the presence of ALAN simply did not hatch, resulting in zero survivorship of offspring. These findings suggest ALAN can signi...