Fish on Prozac

While a story about mellow, happy fish may sound like a sport-fisherman's dream, Prozac in the water could prove to be a fish's worst nightmare. Fish and invertebrates living downstream of urban water and sewage treatment plants around the world have detectable levels of antidepressants in their systems. While actual concentrations in surface waters are low, the active ingredients from antidepressants such as Prozac are causing biochemical, neurological, and physiological damage to a variety of water dwelling creatures.

Pharmaceutical compounds that the human body doesn't metabolize are excreted, and can enter the environment via the septic super-highway, contaminating surface waters downstream. Unused medications are often flushed or trashed, which can increase the amount of these compounds in nature.

Antidepressants (often called SSRI's) block re-uptake of the neurotransmitter serotonin, an ancient and highly conserved chemical present in the brains of many creatures- from invertebrates to humans. At the Society of Environmental Toxicology and Chemistry meeting held this week in Tampa, FL, multiple groups of independent researchers presented evidence demonstrating the effects of SSRI drugs on the nervous systems of fish and invertebrates.

Aquatic life is trying- a never ending struggle between predator and prey. Thus it is important that fish be hyper-aware of their surroundings so that predators don't swallow them whole. In experiments run by Meghan McGee of St. Cloud University, fish that were treated with SSRI's showed impaired startle responses, suggesting that they could more easily fall victim to a predators attack. SSRI's don't help the predators either. Research by Joseph Bisesi, Jr. from Clemson University demonstrated that at high doses of these drugs, hybrid striped bass were significantly slower to capture their prey.

While antidepressants in the water are attracting a lot of attention, previous research has shown that hormones from birth control pills, also present in surface waters, can cause male fish to become reproductively feminized.

Concurrently, multiple health risk prediction studies estimate safe levels of various pharmaceutical compounds in drinking water, which is often purified from the surface and ground waters where potentially affected fish and invertebrates dwell. Because pharmaceuticals in surface waters pose no immediate threat to humans, ecologists and environmental scientists must struggle to bring this issue to the forefront in order to protect aquatic creatures.

Photo credit: Shelly Sanders http://www.betterphoto.com/gallery/dynoGall2.asp?catID=977