[Pharmwaste] Study finds that striped bass exposed to antidepressant Prozac shun food and become easier prey

Tenace, Laurie Laurie.Tenace at dep.state.fl.us
Tue Jul 22 10:27:56 EDT 2008


Happy Fish Go Hungry?
By Adam Marcus 
http://www.sciam.com/article.cfm?id=happy-fish-go-hungry 
                   
What begins in the bathroom often ends in the water supply. No, not that, the
drugs in your medicine chest-and that, a new study suggests, could have a
significant impact on aquatic life.

Toxicologists at Clemson University in South Carolina have found that hybrid
striped bass exposed to the antidepressant fluoxetine (the generic name for
Eli Lilly's Prozac) were markedly less interested in feeding than other fish.
The more fluoxetine ingested, the less the appetite. The fish also did things
that could lead to life-shortening events-like failing to take usual
precautions around predators and making them easier prey.

Fluoxetine and related drugs block the reuptake of serotonin, a
neurotransmitter strongly tied to emotion, by nerve cells, or neurons.  As a
result, more serotonin remains in synapses (small gaps between cells over
which information flows from one neuron to another), which has the effect of
boosting mood. Serotonin is also linked to appetite and aggression.

Study co-authors Stephen Klaine and Kristen Gaworecki exposed hybrid striped
bass, the kind stocked for sport fishing throughout the U.S. Southeast, to
varying amounts of fluoxetine-zero, 35, 75 and 150 micrograms per liter-over
six days, followed by another six-day washout period in clean water.

The concentrations they used were more than 1,000 times greater than those
detected in waste water, Klaine says, noting that the researchers wanted to
determine if-and then how-the drug might affect fish. "We're in the midst of
some longer-term experiments now," he says, "and we're hoping to see
responses at concentrations that would be found in the environment."

Bass were offered four live fathead minnows every three days, during which
the researchers measured the animals' eating habits; they measured serotonin
levels in brains harvested from each bass.

"In general, it took exposed bass longer [than bass not given Prozac] to eat
each minnow," he says. "Some bass exposed to the higher levels of fluoxetine
pretty much gave up trying to capture prey by the third or fourth minnow.
They really didn't have the kind of appetite the controls had."

Bass exposed to  the greatest amounts of fluoxetine acted remarkably
un-basslike, staying at the top of the tank with their dorsal fin above the
waterline or tilting to a vertical position. Such behavior in the wild could
make a bass an easy target for a hungry predator.

Theodore Henry, a fish toxicologist at the University of Tennessee Knoxville,
who has studied fluoxetine's effects on the sexual development of mosquito
fish, says he is "very interested" in the latest findings published in the
journal Aquatic Toxicology. "That is something that we would hypothesize
would happen, that the drug would affect the uptake of serotonin and lead to
behavioral consequences in the fish."


Laurie J. Tenace
Environmental Specialist
Florida Department of Environmental Protection
2600 Blair Stone Road, MS 4555
Tallahassee, Florida 32399-2400
PH: (850) 245-8759
FAX: (850) 245-8811
Laurie.Tenace at dep.state.fl.us 

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