A mussel shell with tube worms attached. Researchers are exploring the use of DNA sampling to give mussel growers more precise information about tube worms which will help them decide the best time to clean shells. Photo: SAIC.

Researchers help mussel growers tackle tube worms

A rapid diagnostic method to support Scotland’s shellfish producers with the early identification of tube worms is being developed by a team of aquaculture experts.

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Led by the University of Stirling’s Institute of Aquaculture (IoA), with support from Shetland Mussels and the Sustainable Aquaculture Innovation Centre (SAIC), the project will use DNA sampling to identify the presence of organisms in water as an alternative to current unreliable testing methods, SAIC said in a press release.

The diagnostic tool will enable producers to make more precise decisions about when to deal with biofouling – the encrustation of mussels’ shells caused by tube worms – including environmental management and cleaning regimes. Similar molecular diagnostic techniques are common in finfish sectors, but the project could represent a significant step forward for shellfish production.

Stefano Carboni: "Shells can be cleaned, but the timing of the process is crucial". Photo: IoA.

Larvae still present

Stefano Carboni, aquatic invertebrate zoologist at the IoA, said: “Shells can be cleaned, but the timing of the process is crucial as larvae may still be present in the water after cleaning, leading to a reoccurrence of the problem.

“Currently the only way to detect tube worms is by looking at a water sample under a microscope, but they can be easily confused with other organisms, and sampling only covers a small volume of water. A more practical and reliable method for identification would be an invaluable development for the industry, which could be applied on a global scale.”

Biofouling affects as much as 10% of Scotland’s mussel stocks each year. Although harmless to consumers, tube worms can cause changes to mussels’ appearance as well as damage to the packaging used. Biofouling can also lead to issues through the production process with some studies indicating problems with shellfish growth and weight caused by the worms.

Cleaning schedules

Initial tests are taking place at one of Shetland Mussels’ sites with the team looking to identify the presence of tube worms through DNA taken from water samples and swabs from shells. Data gathered through the trial will allow researchers to monitor patterns and seasonal variations that could inform cleaning schedules and potential site selection, as well as preventing future losses.

SAIC chief executive Heather Jones said: “Shellfish production is a growing area of the Scottish aquaculture sector, and this project represents just one example of pioneering research that will support further sustainable growth to meet the global demand for protein. New data-led techniques such as this DNA diagnostic tool can help to drive the entire industry forward, with benefits spanning the environment, businesses operating in the sector, and the end consumer.”