Artificial light at night is dangerous for coral reef fish

A new study examined the effects of light pollution on juvenile orange-fin anemonefish

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artificial light at night as seen from the sky

Photo by Jan Huber on Unsplash  

One of the perks of having a window seat in an airplane at night is looking out at the lights below. All that bright light underneath is actually a form of light pollution, or excessive artificial light. Like other forms of pollution, light pollution impacts both terrestrial and aquatic ecosystems. In fact, as of 2010, over 20 percent of Earth's coastlines were lit up artificially at night. As the human footprint on the planet continues to increase, the impact of light pollution on ecosystems remains a concern. 

A recent study sought to understand the impact of artificial light at night by studying long-term effects of light pollution on juvenile orange-fin anemonefish, Amphiprion chrysopterus, within coral reefs of French Polynesia. They raised wild-spawned fish in the lab, and released them either artificially lit coral reefs, or reefs under natural conditions, then monitored their survival for nearly two years. 

The researchers found that exposure to artificial light caused a 36 percent decrease in fish survival and growth, due to the increase of predators due to artificial light and its impact on fish physiology. This study highlights the need to further understand the impacts of light pollution on ecosystems, with the hope that solutions can be proposed in order to limit the impact of human activities on the natural ecosystems around us.