Salmon runs on Canada’s west coast are declining year by year, putting other wildlife such as grizzly bears at risk
It may have been voted one of the world’s top 10 wildlife spectacles by BBC Wildlife experts (January), but the sight of the grizzly bears gathering to feed on salmon in North America every autumn is under threat. Scientists and conservationists working in the coastal rainforest of British Columbia (BC) in Canada detected alarming declines in salmon runs this year that compound steady falls in numbers over the past few decades.
“The usual sounds of fall in BC’s rainforest were agonizingly muted” reported Raincoast Conservation Foundation executive director Chris Genovali after visiting watersheds in central and northern BC in September. “The thrashing of salmon swimming upstream, the splashing of grizzlies pouncing on fish and the cacophony of birds scavenging the leftovers were virtually non-existent”
While nobody disputes that salmon are declining, it is not clear why it’s happening. Conservationists say over-fishing is the primary cause, and that coastal fish farms act as breeding grounds for sea lice that infect wild fish. An increasingly harsh ocean environment caused by climate change is also a probable factor.
But Canada’s Fisheries and Ocean’s department only blames “low ocean productivity and warmer ocean temperatures” for the decline, saying neither aquaculture nor fishing are primary factors. “Returns of pink salmon have been low all along the coast this year, both in areas where juvenile pink salmon were near salmon farms and in areas where they were not” a spokeswoman told BBC Wildlife.
Photographer and presenter Mark Carwadine has visited the region many times. “Salmon are the lifeblood of this wilderness” he said. “This extraordinary diverse ecosystem covers an area twice that of the Serengeti and has greater biological productivity than a tropical rainforest – and a future just as unstable.”
The future of the grizzlies is also uncertain – the absence of the salmon will affect their ability to fulfill their caloric needs, Genovali said, with the result that females may be unable to bear or rear cubs. He recalled the fall of 1999 when one particular sockeye salmon run collapsed. “The bears were starving and wandered into the First Nations village of Owikeeno looking for food – as a consequence, 14 were shot provincial officials” he said.