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Cheap and quick tests being developed to detect shellfish diseases

Scottish-grown oysters. Researchers have been given £200,000 to develop a PCR test for oysters and mussels that will help prevent the spread of Bonamia ostreae and other diseases. Photo: SAIC.
Scottish-grown oysters. Researchers have been given £200,000 to develop a PCR test for oysters and mussels that will help prevent the spread of Bonamia ostreae and other diseases. Photo: SAIC.

Aquaculture researchers in Scotland are developing a PCR method that will help detect the presence of a range of diseases and biofouling species affecting oysters and mussels, in a project that could be a significant boost to the health and wellbeing of the shellfish.

With nearly £200,000 of funding from the UK Seafood Innovation Fund and the Sustainable Aquaculture Innovation Centre (SAIC), the University of Edinburgh’s Roslin Institute will build a validated testing system that allows oyster growers to proactively test for Bonamia ostreae, a common and potentially fatal disease that is otherwise difficult to detect, SAIC said in a press release.

The 15-month project will also receive support from companies and organisations across the oyster farming and research sectors, as well as from practitioners looking to restore the shellfish to their native habitats. This includes the Association of Scottish Shellfish Growers (ASSG), the trade body for commercial shellfish cultivation; the University of Stirling’s Institute of Aquaculture; and rewilding organisations such as Blue Marine Foundation.

What is PCR?

Polymerase chain reaction (PCR) is a fast and inexpensive technique used to "amplify" - copy - small segments of DNA. Because significant amounts of a sample of DNA are necessary for molecular and genetic analyses, studies of isolated pieces of DNA are nearly impossible without PCR amplification.

Often heralded as one of the most important scientific advances in molecular biology, PCR revolutionised the study of DNA to such an extent that its creator, Kary B Mullis, was awarded the Nobel Prize for Chemistry in 1993. Its use is commonplace to detect whether people have the Covid-19 virus.

Source: National Human Genome Research Institute.

Pre-emptive test

Once present on a site, Bonamia ostreae cannot be eliminated and, historically, it has only been diagnosable after infection has occurred. Access to a rapid, cheap, pre-emptive test will help farmers to make more informed decisions on whether to move oysters to different locations, helping to prevent the spread of the disease.

Designed to be affordable and easy to use for growers, the testing system will also detect the presence of oyster herpes virus and vibrio bacteria, along with biofouling species such as tube worms. It builds on a feasibility study conducted earlier this year, which successfully delivered a proof of concept.

Rapid, cheap and simple

Dr Tim Bean, career track fellow at the Roslin Institute, said: “Our project will tip the way we currently diagnose diseases that affect oysters on its head – taking a pre-emptive rather than reactive approach. We are bringing together the right technology with the right people to solve some of the shellfish sector’s biggest health challenges and potentially make significant improvements to oyster health.

“This rapid, cheap and simple process will allow farmers and restoration practitioners to make more informed decisions about whether to move animals, optimising biofouling treatments and site selection. Shellfish growers are often smaller businesses, which makes it all the more important the testing equipment is readily available, easy to use, and affordable.”

Scotland has retained a disease-free status for oyster herpes virus [and] with improved detection methods, we would continue to seek to sustain this position, giving us advantages over shellfish production in surrounding countries

ASSG chief executive Nick Lake
Dr Nick Lake: Testing system will benefit shellfish growers tremendously.
Dr Nick Lake: Testing system will benefit shellfish growers tremendously.

Dr Nick Lake, chief executive of the ASSG, said: “The development and use of a proactive testing system will benefit shellfish growers tremendously. Tube worm casts, while benign in terms of mussel quality, are difficult to remove and can interfere with packaging and presentation.

“Equally, Scotland has retained a disease-free status for oyster herpes virus, which causes losses of young shellfish. With improved detection methods, we would continue to seek to sustain this position, giving us advantages over shellfish production in surrounding countries. The industry is pleased to support this further development of techniques that will support our climate change resilience in the coming years.”

More data than ever

SAIC chief executive Heather Jones said: “The development of an accessible, rapid test for a range of diseases that affect oysters will be invaluable for the sector. Armed with this testing system, growers and professionals looking to restore the species to habitats will be able to prevent the spread of the disease and act on more data than they have ever had, to the benefit of oyster health and wellbeing. This project is another great example of how collaboration can bring people and technology together to address one of the biggest challenges faced by the shellfish sector.”