The influence of spectral composition of artificial light at night on clownfish reproductive success

Artificial light at night (ALAN) is increasingly recognised as a major threat to conservation, causing physiological and behavioural impacts on species adapted to a predictable day-night cycle, including the disruption of reproductive processes. This study investigates the influence of spectral composition of ALAN on Amphiprion ocellaris reproductive success. We compared spawning frequency, clutch size, embryo quality and hatching success of A. ocellaris exposed to ALAN with warm-white and cool-white spectra to fish held in control (12 h day: 12 h night) conditions. The presence of ALAN, regardless of light colour treatment, increased the interval (number of days) between spawning events, and eggs developing under ALAN were smaller than eggs developing under control conditions. Hatching success was influenced by both the presence of ALAN and spectral composition of the light, with fewer embryos hatching under cool-white light compared to warm-white light treatments. As light pollution continues to spread, more research is needed to understand the extent of the impacts of ALAN on marine organisms and to identify effective management strategies.