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How beer is helping salmon find its way back home

25 July 2023 By Sarah Neish

Beer yeast is being used in Oregon to help salmon ‘smell’ their way back to hatcheries where they were born in order to lay their eggs.

Like a GPS system for fish, brewer’s yeast can help to direct salmon back to hatcheries where they can safely spawn their eggs.

When salmon are born they tune into the scent of their surroundings, imprinting the smell on their memory and leaving traces of its molecules through the water in a kind of breadcrumbing exercise to enable them to return to the same spot as adults to lay eggs of their own.

Researchers at The Oregon Hatchery Research Center (OHRC) in Oregon have been experimenting with different ingredients to determine which smells salmon might recognise most easily in order to help them make it back home to the hatcheries where they were born.

Some of the compounds that have been trialled include: extract of shrimp; tincture of watercress; skin of steelhead, and bile of minnow.

The team discovered that one particular amino acid was especially effective in luring the salmon back, and this amino acid is found in a potent byproduct of the brewing process called ‘trub’; effectively a gloopy, coagulated mess of unfermentable fats, proteins, and yeast.

“We could see the introduction [of the trub] triggered immediate positive responses from the fish,” Marc A. Johnson, a fisheries and conservation biologist who works for the Oregon Department of Fish and Wildlife, told Oregon Live.

The researchers have now been given a grant to continue this beer yeast research for the next two years.

If their work continues to prove successful, it may take five to 10 years to implement it in Oregon’s salmon hatcheries.

It could also be an important breakthrough in terms of how breweries dispose of their waste, and could be extended beyond Oregon to other locations where salmon populate local waterways.

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