Artificial light is keeping reef fish awake, and the effects may ripple across coral reefs

Artificial light spilling into coastal waters from cities, ports, roads and hotels is disrupting sleep in coral reef fish and is associated with changes in markers linked to brain health, according to a new study from Bar-Ilan University. The paper, published in Current Biology, shows that even low levels of nighttime illumination can significantly alter the behavior and physiology of reef fish. Fish exposed to artificial light slept less, showed more fragmented sleep, became more aggressive and fed at unusual hours, effectively behaving as if night had turned into day.