She-Males of the Sea

Sunscreen may alter fish sexually, according to study.


ROLE REVERSAL: Some bottomfish off SoCal are getting sex changes.
Illustration: Jorge Colombo

A chemical in sunscreen is causing male bottomfish off Southern California, such as halibut and sole, to develop ovary tissue and female egg proteins.

Oxybenzone, which protects our skin from ultraviolet rays, shares some chemical properties with estrogen and is ending up on the ocean floor, says Dan Schlenk, a professor of aquatic eco-toxicology at the University of California at Riverside. When beachgoers go home and hit the showers, oxybenzone washes down the drain, survives the sewage-treatment and outfall process and ends up right on the dinner plates of a few hungry male bottomfish.

So what does this growing population of bearded-lady bottomfish mean for future stocks? Not much apparently. Schlenk said the mixed-gender fish still have the ability to reproduce.