Randall Peterman of the Simon Fraser University. (Photo: YouTube, SFUNews/Fisheries and Oceans Canada)

North Pacific swarming with salmon

CANADA
Monday, October 04, 2010, 23:40 (GMT + 9)

A Canada-US research team has documented more pink, chum and sockeye salmon in the North Pacific than ever before. This constitutes about twice as much fish as existed in the 1950s, according to the team’s published article in Marine and Coastal Fisheries: Dynamic Management and Ecosystem Science.

The 2005 figures show that 718 million adult salmon returned to their freshwater homes. The North Pacific is “overcrowd[ing] with salmon,” told Randall Peterman, the Canada Research Chair in Fisheries Risk Assessment and Management, and a member of the research team, according to Globe and Mail.

Unfortunately, the team determined that the vigorous adult salmon population was pumped by the yearly release of some 5 billion juvenile salmon from hatcheries mainly in Japan and Alaska, Professor Peterman of Simon Fraser University said.

Adult salmon from hatcheries now make up at least 20 per cent of the total adult salmon production and are rising. The percentage is much higher for certain salmon.

Peterman warned that hatchery fish may dominate the ocean if international agreements are not created to manage production levels.

In light of the federal commission’s investigation on the disappearance of salmon on Canada’s West Coast, the international trend toward greater abundance is not uniform throughout the North Pacific, and the population in areas like British Columbia’s (BC) Fraser River remains worrisome.

“Indeed, many pink, chum and sockeye salmon are at very low levels and that is true for the Fraser sockeye salmon in particular,” Peterman noted.

“But if you look across the North Pacific, to Asia and other parts of North America, the total salmon abundance is quite high. […] This is something that most people don’t recognize,” he said.

Regarding this year’s unprecedented 34 million salmon return to the Fraser River, he said one year does not make a trend.

Peterman surmised that increased survival rates may be due to few predators or more food as well as the hatcheries’ escaped fish, which enter wild streams and interbreed.

“It degrades the fitness of the wild population. The wild population has a store of genetic material that enables them to respond to a variety of situations, like climate change,” he explained.

Thus, if the hatchery fish dominate the wild stock, they may not survive if environmental conditions like climate shift, as their offspring are less capable of enduring factors that concern their survival, he said.

As BC salmon migrate into the Pacific Ocean and the Gulf of Alaska, they intermingle with hatchery fish from Japan and Alaska.

“Unilateral actions by various hatcheries is having detrimental effect on salmon everywhere,” he said.

The Cohen Commission researching the decline of the Fraser River salmon was not looking into hatcheries as a possible cause for the decline. If credible evidence becomes available, however, the commission will consider it, said Commission Spokeswoman Carla Shore.

Related articles:

- Cause of record Fraser sockeye salmon run a mystery
- Pacific sockeye salmon return in record numbers
- Sockeye run estimates upped to 34 million

By Natalia Real
editorial@fis.com
www.fis.com

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