Why mussels may become too toxic to eat

MUSSELS could become inedible within the next 100 years as rising sea temperatures could make them too toxic for humans, a study suggests.

Research has indicated that a change in temperature of just 2C could make mussels, oysters and other popular shellfish poisonous to humans.

Climate change models predict that sea temperatures will rise significantly in the next century, causing massive disruption to marine habitats. In these areas, rainfall is also predicted to increase, reducing the salt concentration of the surface layer of the sea.

Plymouth University researchers said these changes would dramatically affect the microscopic communities of bacteria and plankton that inhabit the oceans, affecting species higher up the food chain.

Future conditions are expected to favour disease- causing bacteria and plankton species which produce toxins, including the lethal paralytic shellfish toxin. These can accumulate in shellfish, putting people who eat them at risk.

Researchers investigated how climate change was likely to affect the fledgling Green Mussel industry in South West India.

The scientists raised mussels under high temperature and low salt conditions while exposing them to toxic plankton and bacteria species.

They found that the combination of a warmer temperature and reduced salinity had a significant effect on the health of the mussels.

Lead investigator Dr Lucy Turner warned this could threaten the tropical shellfish industry, already under pressure from India’s increasingly urbanised population.

Now the researchers plan to determine whether similar results are observed for oysters and clams, while a sister project is investigating how climate change may affect prawn farms.