Giant mussels found in UK waters under threat due to conservation ‘failures’

A species of large mollusc could be at risk due to unprotected areas of the sea near its bed, a new study has found.

Marine Scotland:Horse mussels have been known to be in decline since the 1990s

Measuring up to 20cm in length, horse mussel can live for several decades and are found mainly around the north of the British Isles.

Marine experts have described their beds as “biodiversity hotspots”, providing foundations for soft corals and barnacles, as well as shelter for many small sea creatures and habitat for shellfish.

Their decline has been known about since the 1990s, and marine protected areas (MPAs) were introduced to protect their numbers.

But a new study by scientists at Heriot-Watt University in Edinburgh shows the species is at risk due to a “failure” to consider gaps between protected areas of the sea where their beds lie.

Dr Jo Porter, based at Heriot-Watt’s Orkney campus, worked alongside a team of scientists and researchers to sample horse mussel beds around Scotland and analyse their DNA.

She said: “We wanted to find out whether these areas are actually doing their job of protecting the horse mussels and how they operate as a network.

“This is especially important because, like many protected marine species, the larvae spend time travelling in the plankton before they settle.