Crabs exposed to Prozac, a drug used to treat depression and other mental health disorders, causes them to engage in risky behavior.
In a study, researchers found that Oregon shore crabs exposed to the drug exhibit behaviors that make it easier for predators to catch them.
The study is important because it sheds light on how pharmaceuticals found in the environment could affect animal behavior and survival.
In a study, researchers found that Oregon shore crabs (picutred) exposed to Prozac, a drug used to treat depression and other mental health disorders, causes them to exhibit behaviors that make it easier for predators to catch them
According to researchers from Portland State University (PSU), tests of seawater near areas of human habitation have shown trace levels of everything from caffeine to prescription drugs for years.
The chemicals end up in the water after they’re flushed from homes or medical facilities, and they go into the sewage system, eventually making their way to the ocean.
So PSU researchers conducted a study to see what would happen to Oregon shore crabs (Hemigrapsus oregonensis) exposed to traces fluoxetine, the active ingredient in Prozac.
The Oregon shore crab forages mostly at night, primarily eating algae but also carrion and other meat if it’s available.
It lives most of its time on, beneath, or near rocks in gravel and fine sediment substrate, and to escape predators, it usually quickly burrows in sediment or hides beneath rocks, and also relies on camouflage while staying still.
The red rock crab (Cancer productus) preys on Oregon shore crabs, amongst other species, and was used in the experiment too.
Pictures of (a) an Oregon shore crab (Hemigrapsus oregonensis) in the aquarium habitat, (b) example of the tank set up with sides blacked out, (c) addition of a red rock crab (Cancer productus) during predator trials, and (d) an observer recording crab behavior at night
Specimens of each species were placed in tanks for a 9-week period of exposure to fluoxetine.
The animals were fed regularly and the tanks contained sand and pebbles for burrowing.
Each week, the researchers conducted four trials with and without a predator, observed during the day and night.
Following their analyses, the researchers found that the Oregon shore crabs increased their foraging behavior, showing less concern for predators than they normally would.
The red rock crab (Cancer productus, pictured) preys on Oregon shore crabs, amongst other species, and was used in the experiment to see how Oregon shore crabs behave in response to predators
They crabs even foraged during the day, when they would normally be hiding.
The shore crabs also fought more with member of their own species, often either killing their foe or getting killed in the process.
‘The changes we observed in their behaviors may mean that crabs living in harbors and estuaries contaminated with fluoxetine are at greater risk of predation and mortality,’ said researcher Elise Granek, a professor in PSU’s department of Environmental Sciences and Management.