Stressed Out Fish

February 25, 2007
By Damond Benningfield

The word “steroids” may conjure images of bulky baseball players, or of cancer patients undergoing treatment. But steroids aren’t just drugs for bodybuilders and medical patients. Naturally occurring steroids are important hormones that help control reproduction and other bodily functions.

An Atlantic stingray in an aquarium in Weeks Bay National Estuarine Research Reserve. Photo: National Oceanic & Atmospheric Administration Central Library

Steroids may also play a role in how we handle stress. To find out more about that, researchers are studying steroids in fish to see if they are involved in adapting to environmental stresses.

In one study, researchers are looking at stingrays captured along the Texas Gulf coast. The rays can go from freshwater to saltwater in just a few hours with no ill effects -- something that most fish can’t handle.

Researchers are changing the rays’ environment from saltwater to freshwater with no salt at all, producing a sudden stress on the system. The scientists then measure how the rays’ blood chemistry changes as they adapt to the environment. Early results suggest that steroid production increases, so the steroids appear to be involved in helping the animals handle the stress.

In people, stress causes the body to produce more energy, and to shut down unnecessary systems. That’s fine for a little while, but if the stress lasts for long, it can cause big problems. Steroids may play a role in regulating this process. If so, then the marine research may shed some light on how it works -- leading to a better understanding of how the body handles the stresses of everyday life.


copyright 2006, The University of Texas Marine Science Institute