Study finds mussels feel ‘stress’ from passing ships

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They do not have ears, brains, or central nervous systems, but the humble mussel is still capable of suffering from stress as a result of passing water traffic, according to new research.

The underwater noise emanating from ships can impact on the growth of the molluscs, and may even help explain a decline in mussel banks in some areas of the country, say a team of Scottish scientists.

While the ship noise is not “immediately dangerous” for the creatures, researchers say it impacts on their DNA.

Mussels are suffering from stress as a result of underwater noise from ships, research suggests.

While previous studies have looked at how noise affects larger marine creatures, such as whales and dolphins, the marine scientists at Napier University and Heriot Watt University, say their findings show mussels can detect changing sound levels in their environment.

They collected mussels from the shore at Musselburgh, outside Edinburgh, and tested their response to noise in a lab at the St Abbs Marine Station near Eyemouth, a charity dedicated to marine science, conservation and education.

Karen Diele, from Edinburgh Napier University, the co-director of research at the marine station, said: “We recorded and played the sound of a ship’s motor to a sample of blue mussels in a controlled setting, and measured biochemical and behavioural changes in the mussels.

“For the first time in a marine species, we detected noise-induced changes in DNA integrity, indicating an underlying source of stress.”

Matt Wale, also from Edinburgh Napier University, said the mussels that had been exposed to noise consumed 12 per cent less oxygen, which led to increased energy use and potentially slower growth.

Mark Hartl from Heriot-Watt University, said the effects of the noise had clear repercussions.

He explained: “Given the wide distribution of mussels in areas where they may be exposed to noise, the impact of noise does not appear to be fatal or immediately dangerous for mussels.

“However, this doesn’t mean it isn’t having a long-term effect on mussel populations in high noise areas, it could be affecting their growth, reproductivity and may help explain the decline of mussel banks in some areas of the UK.”

“It’s important that we understand how noise is stressing mussels in environmental risk assessments so that we can ensure environmental policy and regulation is effective.”

The researchers received funding from the Marine Alliance for Science and Technology for Scotland.