Oct. 23 (UPI) -- Exposure to pharmaceuticals is a growing problem for coastal wildlife. New research suggests the behavior of Oregon shore crabs is influenced by the antidepressant Prozac.
In the lab, scientists from Portland State University exposed Oregon shore crab specimens to trace amounts of fluoxetine, the active ingredient in Prozac. Crabs exposed to the drug were more likely to forage, ignoring the threat of predators. Crabs exposed to fluoxetine also foraged during the day, when the crustaceans would typically be hiding.
The findings -- published last week in the journal Ecology and Evolution -- suggest the drug lowers the crabs' inhibitions, causing them to taker greater risks.
The drugged crabs also engaged in more aggressive behavior, getting in fights with both friend and foe. Crabs exposed to the antidepressant were more likely to get killed or injured in duels with their peers.
Lead researcher Elise Granek told UPI the crabs were not exposed to unrealistically high doses in order to elicit a dramatic reaction.
"Many labs study the effects of very high concentrations of pharmaceuticals on organisms -- much higher than we would find in our waterways," Granek said in an email. "In our lab, all of the concentrations we use in our experiments are levels that have been measured in bays and/or estuaries on the U.S. West Coast."
Granek has previously conducted research showing small doses of antibiotics slowed the growth of mussels -- "likely because their gut biota are disrupted when exposed to antibiotics," she said.
Some scientists hypothesize that because pharmaceuticals boast relatively short half-lives and can attach themselves to sediment particles, filter feeders and scavengers who eat detritus -- those who process lots of water and sediment -- may be more likely to accumulate pharmaceutical compounds.
But researchers have also found significant concentrations of drugs in juvenile salmon living the Puget Sound, suggesting a wide variety of organisms are at risk.
"Since we don't know the extent to which prey species can pass these contaminants on to their predators, it is a bit hard to say whether crustaceans are truly more vulnerable," Granek said.
Granek says drug companies and pharmacies need to do more to ensure medications are properly disposed of so they don't end up in local waterways.
"A possible approach policy makers could take is to mandate that all pharmacies that dispense pharmaceuticals have to also have drop boxes to take back unused pharmaceuticals," Granek said. "Some pharmacies are doing so voluntarily, but it is not required, so these pharmacies are few and far between."