How mussels and oysters could become deadly due to climate change
Rising sea temperatures combined with increased rainfall in tropical areas will reduce the salt concentration of the surface layer of the sea, Dr Lucy Turner, a biologist from Plymouth University in the UK explains.
This would dramatically affect the microscopic communities of bacteria and plankton that inhabit the oceans, impacting species higher up the food chain.
These conditions may favour disease-causing bacteria and plankton species which produce toxins, such as the lethal PST (paralytic shellfish toxin), which can accumulate in shellfish such as mussels and oysters, putting human consumers at risk.
Turner describes recent research investigating how climate change is likely to affect the fledgling Green Mussel industry in South-West India.
Working on the Mangalore coast, the scientists raised mussels under high temperature/low salt conditions whilst simultaneously exposing them to toxic plankton and bacteria species. The results showed that the combination of both a warmer temperature and reduced salinity had a significant effect on the health of the mussels.
"If the changes in the environment put the mussels' bodies under higher stress levels than usual, and we then challenge them with these microorganisms, the immune system may become compromised," Turner said.
According to Dr Turner, this could threaten the rapidly-growing tropical shellfish industry, already under pressure from India's increasingly urbanised population.
"The demand for marine products is growing at an unprecedented rate...there is also a drive to move from small scale fishing methods to larger scale commercial operations".