Hatchery International

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High hopes for new trout disease vaccine in Scotland

July 18, 2019  By Mari-Len De Guzman

The RTFS is a common disease in trout and tends to affect trout at a very small size, rendering injections unsuitable.

A consortium of fish farmers and aquaculture research organizations in Scotland have teamed up to develop a commercial vaccine for Rainbow Trout Fry Syndrome (RTFS), a pervasive disease among trout.

The initiative is spearheaded by UK’s largest rainbow trout producer, Dawnfresh, and the University of Stirling’s Institute of Aquaculture. Scottish trout farmer, Kames Fish Farming, and aquaculture research firm Tethys Aquaculture, with funding from the Scottish Aquaculture Innovation Centre (SAIC) are also part of the project.

The group will conduct field trials of the new vaccine in a bid to secure the necessary licence for commercial use. The vaccine was developed by the University of Stirling as part of a five-year European Commission-funded project called ‘Targetfish’.

RTFS has been a major problem for the rainbow trout industry, according to Dr. Rowena Hoare of the University of Stirling’s Institute of Aquaculture. “We are delighted that this project has been funded by SAIC, enabling our novel RTFS vaccine to be tested on two fish farm sites. We hope in the future to combine this with other vaccines to assist in the sustainability of the trout industry.”


RTFS is a common disease in trout and has been responsible for substantial loss of stocks, with some sites reporting high average early-stage mortality rates. Rainbow trout is the second most-produced finfish by volume on UK fish farms, making RTFS a particularly important issue on British shores.

However, the diversity of the bacteria that cause RTFS has made vaccine development challenging, while the very small size at which fish tend to be affected renders injections unsuitable, according to the SAIC.

“Although antibiosis is a treatment option, the industry’s drive to minimise antibiotic usage, reduce losses, and improve welfare required a new approach,” the SAIC said in a statement.

In an effort to find a solution, the University of Stirling developed a dip vaccine for trout which can be administered to fry in a very low-stress and low-risk manner. Proponents are hoping that the vaccine, combined with best farm management practices, will protect the fish until they are large enough to fend off infection themselves.

“We are constantly striving to improve sustainability, health and welfare within the trout farming sector. We believe this vaccine could bring great benefits in these areas, as well as the potential to reduce antibiotic usage even further to some of the lowest levels for all food-producing animals,” said Richard Hopewell, fish health manager at DawnFresh.

The vaccine, if successful, could be significant for fish well-being and the trout farming industry, according to Polly Douglas, aquaculture innovation manager at SAIC.

“If successful, this vaccine could provide a sustainable foundation for growing trout farming in the UK, unlocking additional capacity for the sector and potentially leading to a significant reduction in cost. It’s another example of how industry and academia can work together to solve some of the biggest problems faced by aquaculture,” Douglas said.

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