Pink salmon in sharp decline near Broughton fish farms
Numbers spawning in five key indicator streams down 90 per cent
Scott Simpson
Vancouver Sun
Friday, October 31, 2008
A stunning collapse of pink salmon runs on the British Columbia central coast is reopening a charged debate about the looming extinction of wild salmon that breed near fish farms.
The number of pink salmon spawning this autumn in five key indicator streams in the Broughton Archipelago area has dropped as much as 90 per cent compared to their parent runs in 2006, and constitutes only about two per cent of pink salmon abundance in the year 2000.
Counts of spawning fish, which will be finalized early next month, underscore predictions published last year in one of the world's foremost research journals, Science, that pink salmon will be extinct in the Broughton by 2015.
The Dec. 14, 2007, Science article grabbed international headlines, sparking 500 news articles, particularly in nations with large aquaculture operations.
The article's authors asserted a link between the decline of Broughton pink salmon populations and hyper-concentrations of sea lice at salmon farms in the area, with juvenile pinks devastated by louse infestations arising from the farms.
One of the authors, Martin Krkosek, won a Governor-General's Gold Medal for PhD research into links between sea lice and salmon while another, Alexandra Morton, is awaiting a B.C. Supreme Court ruling on her challenge of the province's authority to regulate and approve salmon farm locations.
The article was condemned by salmon farmers and government scientists in B.C., who called its conclusions premature.
Earlier this month, Fisheries and Oceans Canada reported that pink salmon spawners coming back to the region's primary indicator stream, Glendale Creek, were substantially lower than the 2006 parent brood year -- roughly 15,000 compared to 182,000 two years ago.
Four other streams are also down.
Morton said sea lice are not the only threat to young migrating wild salmon -- but suggested the government should take action to give the fish a chance to recover, including closing fish farms along migration routes.
"When you are down this low you are about to extinguish the DNA that is in these fish which are built for this river.
"They've got to move some farms out of there right now."
Krkosek said a full assessment of the situation will require spawning data from streams outside the Broughton study area -- to determine if ocean survival factors came into play.
But he agreed with Morton that it was better to be cautious.
"In a situation like this where you have really, really depressed salmon populations, management should be doing everything they can to improve the survival of the fish that are remaining," he said.
Fisheries and Oceans Canada, which acts as as strong proponent of salmon farming, declined The Vancouver Sun's request for comment.
Ian Roberts, communications manager for Marine Harvest Canada, agreed outside factors may have had an impact on Glendale.
But he noted that Marine Harvest supports research to reduce potential fish farm impacts.
Beginning in 2010, the company will each year alternately fallow farms along one of two migration routes, and will not pen adult salmon on either of those routes when pink salmon fry migrate in spring.
He also noted that 2007 was the lowest year on record for intensity of sea lice infestations on the fish the company produces at its Broughton farms.
"We obviously know there is an impact.
"We've never said at what level that impact might be but certainly we will do whatever it takes to ensure we are minimizing the risk."
ssimpson@vancouversun.com© The Vancouver Sun 2008