Light pollution in shallow coastal waters: aquaculture farming in the Galician Atlantic shoreline

TL;DR

This study quantifies the significant increase in light pollution caused by LED floodlights in Galician Atlantic aquaculture farms, highlighting environmental concerns and advocating for reduced artificial lighting in coastal areas.

Contribution

It provides the first detailed measurement of light pollution levels in shallow coastal aquaculture settings and discusses environmental impacts and policy implications.

Findings

Light levels are 125 times higher than natural night conditions.

Artificial lighting persists all night, significantly affecting local ecosystems.

The efficacy of floodlights for theft prevention is questionable.

Abstract

Artificial light at night is a relevant environmental stressor whose unwanted consequences have been documented by a growing body of research. In this work we analize the loss of the natural darkness of the night in aquaculture farms located in shallow waters close to the shoreline, in the Atlantic coast of Galicia. High-luminance LED lampposts are switched-on the whole night long for surveillance purposes, significantly increasing the light levels throughout the whole water column, from the surface to the seabed. Measured in terms of the weighted radiance associated with the significant magnitude m1/3, the zenithal brightness at these locations is 125 times higher than should correspond to a pristine natural site. Given the potential severity of the environmental effects of artificial light at night, the dubious efficacy of light per se as a theft deterrence factor, and the availability of more efficient and environmentally friendly technologies for surveillance, the use of permanent floodlight sources in coastal areas is strongly discouraged and should be restricted as much as possible.