David Suzuki: Repressed science shows that ponds endanger wild salmon

A 2021 UBC study confirmed that farmed fish transmitted a highly contagious virus to wild salmon, affecting the ecosystem


The story of the wild Pacific salmon is a compelling illustration of the interconnectedness of nature. For more than seven million years, fish have followed a cycle from lakes, streams and rivers, across estuaries to the Pacific Ocean, where they swim long distances, feed and grow for years – and face many obstacles to survival.

Once mature, the surviving salmon embark on a strenuous journey upstream, returning to spawn and carrying nitrogen accumulated in the ocean. Along the way they feed on whales, humans, bears, birds and more. Their nitrogen-rich remains, extracted from the waters by bears and eagles or dumped, fertilize the magnificent coastal rainforests.

One significant link is between Chinook salmon and the beloved but endangered Salish Sea orc, of which there are only 74. These whales feed exclusively on Chinook. Like sockeye, pink and other salmon, Chinook populations are battling under a salvo of threats, including climate change, habitat destruction, fishing, pollution and ponds.

Parasites, diseases and potential escape from open-net ponds endanger all wild Pacific salmon, including the Chinook. Shockingly, this evidence is not new – but some has been suppressed for a decade. In 2012, biologists from Fisheries and Oceans Canada studied the presence of the highly contagious Piscine orthoreovirus, or PRV, in wild and farmed salmon.

The current federal government has promised to phase out open salmon farms in Pacific waters by 2025, but it and previous governments kept the study secret until March, when it was finally released after years of challenging access to Wild First information.

PRV causes anemia and jaundice in farmed salmon and can spread to wild salmon. The study showed that it is uniquely harmful to Chinook, causing their blood cells to burst, which leads to damage to the kidneys and liver. The virus did not originate from BC waters, but was found in Atlantic salmon – a species bred in BC

A 2021 study from the University of British Columbia confirmed that farmed fish transmit PRV to wild salmon and found that the proximity of fish farms increases the likelihood of infecting wild Chinook. One of the authors of the original DFO study, federal biologist Kristi Miller-Saunders, called the delay a “pavesty” that contributed to the constant suspicion of the viral effects of fish farms on wild salmon.

That suspicion has led to joint efforts by the aquaculture industry and its supporters to oppose government plans to phase out farms. They claim that this will mean killing millions of farmed salmon and causing numerous job losses.

But as independent biologist Alexandra Morton – who has studied fish for 30 years – told The Guardian, “The industry needed to know it was coming and seeing the inscriptions on the walls. They needed to start moving to different types of enclosures. Instead, they have relied on the government for years – the Department of Fisheries and Oceans – to hide their sins. ”

Morton and other biologists have argued that farmed salmon can also transmit potentially deadly sea lice and mouth rot to wild salmon.

The department said its decision to deny the report was based on disagreement among the groups participating in the study, which was funded by the Joint Aquaculture Research and Development Program and Salmon producer Creative Salmon. But ordering the department to release it, the federal information commissioner said Wild First’s challenge was “well-founded” and that covering up the report was not justified.

The problem is when the federal department in charge of conserving wild salmon also supports the interests of the aquaculture industry. As is often the case, short-term economic arguments prevail over current and long-term environmental protection. But wild salmon – and orcs, bears, eagles, rainforests and the people they support – are too important to sacrifice for profit for a harmful industry that should clean up its act.

Despite some setbacks, the federal government seems to take the conservation of salmon (and orcs) seriously and sticks to its plan to phase out farms – something the public should support. If salmon is farmed, it should be farmed in closed plants, preferably on land, with care to reduce or eliminate all other environmental impacts.

Helping wild salmon survive and thrive means reducing threats against them – from climate change and pollution to hatcheries and ponds.

David Suzuki is a scientist, broadcaster, author and co-founder of the David Suzuki Foundation. Written with contributions from senior writer and editor of the David Suzuki Foundation Ian Hannington.

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