Water pollution could put shrimp survival at stake
by Lewis Smith
July 07 2010 Fish2Fork
Cold-water shrimp found around the British coast
Antidepressants escaping into rivers and seas could turn shrimps suicidal, researchers have found.
Shrimps exposed to antidepressants at levels contained in waste water have been found to suffer behavioural changes.
Instead of keeping to the safety of the shadows the crustaceans swim towards the light where they are more easily snapped up by fish, birds and other predators.
Researchers fear that drugs are escaping into the environment through waste water outlets in such great quantities that they will affect animals in the wild.
The consequences of shrimps losing their natural caution could be serious for both the species and the wider ecosystem.
"Crustaceans are crucial to the food chain and if shrimps' natural behaviour is being changed because of antidepressant levels in the sea this could seriously upset the natural balance of the ecosystem," said Dr Alex Ford from the University of Portsmouth's Institute of Marine Sciences.
Scientists at Portsmouth looked at the effect of the antidepressant drug fluoxetine and calculated that shrimps exposed to it at levels found in waste water flows into rivers and estuaries were five times more likely to swim towards brighter areas. They report their findings in the journal Aquatic Toxicology.
Dr Ford added: "Much of what humans consume you can detect in the water in some concentration. We're a nation of coffee drinkers and there is a huge amount of caffeine found in waste water, for example. It's no surprise that what we get from the pharmacy will also be contaminating the country's waterways.
"Effluent is concentrated in river estuaries and coastal areas, which is where shrimps and other marine life live - this means that the shrimps are taking on the excreted drugs of whole towns.
"He started looking at the effects of drugs in waste water because a species of parasite is known to alter shrimp behaviour by changing the quantities of serotonin in their brains. Seratonin levels in humans are closely linked to treatment for depression.
In 2002, according to the Office for National Statistics, there were 26.3 million prescriptions for antidepressants in England and Wales alone.
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