Breeding salmon to resist sea lice can cut chemical use

Selective breeding can produce salmon resistant to sea lice, according to a study.

Breeding salmon to resist sea lice can cut chemical use

Chemical treatments are the current mainstay of controlling infection but an increasing drug resistance among sea lice means an alternative is urgently required, scientists warned.

It is needed to reduce the threat posed to the welfare of farmed Atlantic salmon and the sustainability of fish farming across the world, they said.

The team at the University of Glasgow said it has developed a simple protocol to breed fish resistant to lice.

The researchers have also produced a mathematical model to predict the response to selection.

Results have indicated that fish respond quickly to selection and resistant fish populations will require substantially fewer treatments to control lice.

The study, published in the Royal Society journal Interface, found in some instances as few as 10 generations may produce fish that naturally control infection and seldom require treatment Professor Michael Stear said: “Sea lice infection is a major threat to the health of farmed salmon and to the fish farming economy.

“Our research has produced a practical tool for quantifying resistance to sea lice and shown that selection could substantially reduce the need for drug treatments.

“Selective breeding for sea lice resistance should reduce the impact of sea lice on fish health and thus greatly improve the sustainability of Atlantic salmon production.”

WWF Scotland director Lang Banks said: “There is no doubt that sea lice are a major problem for the salmon farming industry and that large amounts of chemicals are currently used to combat the problem.

“If we are to protect the wider environment, then finding ways to reduce the industry’s reliance on chemicals is to be welcomed.

“However, as chemical use is only one of a number of environmental impacts from salmon farming, we need to see more farms sign up to the Aquaculture Steward Council’s ‘responsible farming’ labelling scheme, and pledge to operate more sustainably in all aspects of their operations.”

A report by the UN recently forecast that demand for fish would outstrip demand in the coming years.

Fish consumption is growing at a faster pace than beef, pork and poultry, driven by an expanding, increasingly prosperous global population that recognises the heath benefits of eating seafood.

Wild fish stocks will not be able to fill the gap, the report found, which means fish farming and lakes and coastal waters, also known as aquaculture, to make up the shortfall.

A seafood industry analyst has predicted billions of euros worth of takeovers of companies involved in fish farming as businesses try to capitalise on the rising demand.

“We can expect that large companies, active in commodities, animal proteins, and life sciences will be considering this industry and how they can play a role in the growth of what some call the ‘Blue Revolution’,” Gorjan Nikolik said.

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