Wild Pink Salmon Crash Blamed on BC Fish Farm Lice p1 of 2

Wild Pink Salmon Crash Blamed on BC Fish Farm Lice

By Gordon Young

VANCOUVER, British Columbia, Canada,
November 25, 2002 (ENS)

The environmental impacts of commercial salmon fish farms on the west coast likely caused the collapse of one set of wild salmon stocks, according to a fisheries council report issued today.

The Canadian government funded council urged precautionary measures to prevent further destruction of Pacific wild salmon in British Columbia waters, where a wild salmon fishery has been crucial to the economy for more than a century.

The Pacific Fisheries Resource Conservation Council (PFRCC)
identifies sea lice escaping from open net salmon farming pens
as the probable cause of a collapse last summer of wild pink
salmon stocks in the Broughton Archipelago on northern Vancouver Island.

Former Speaker of the House of Commons and federal
fisheries minister, John Fraser now chairs the Pacific
Fisheries Resource Conservation Council.

(Photo courtesy
Government of British Columbia)

In a 12 page advisory letter, PFRCC chair John Fraser, a former federal minister of fisheries, explained that the Council’s primary concern is “to protect and provide safe passage for the 2002 pink salmon brood year on their seaward migration through the Broughton Archipelago."

"In numerical terms, the number of pink salmon spawners in the Broughton Archipelago decreased from 3.615 million fish to 147,000 fish,” Fraser wrote in the letter to federal Fisheries and Oceans Minister Robert Thibault and provincial Agriculture, Food, and Fisheries minister John van Dongen. Neither minister immediately commented on the report.

Pinks, the smallest of the five Pacific salmon species, return to their home rivers in rigid two year cycles. Leaving their native rivers as tiny smolts, they swim out to the open ocean to feed and grow, returning to their native rivers as two to four pound adults ready to spawn.

Fraser said, “Spawner declines were virtually confined to the Broughton Archipelago, leading us to conclude that the decrease was specific to conditions in the Broughton and was related to conditions within the Broughton Archipelago."

"There is evidence that the Broughton pink juveniles were infested with sea lice, a condition essentially unreported for juvenile pink salmon in the natural environment elsewhere,” he wrote.

Sea lice are naturally occuring parasites on adult salmon,
and they seem to do the larger fish little harm. The 21
commercial fish farms in the Broughton Archipelago use
imported Atlantic salmon as their stock, which, though
they have proven better suited to domestic production
than Pacific salmon species, are also better hosts for sea lice.

Pink salmon smolts infected with sea lice
(Photo courtesy Alexandra Morton)

Environmentalists believe that massive outbreaks of sea lice in the commercial pens boosted local lice populations to plague levels. The sea lice
then attacked juvenile pink salmon migrating out
to sea in April 2001, killing off that brood year,
and this attack led to the lack of adult pink
spawners last summer. Though levels of pink
salmon populations do fluctuate widely on their
own, scientific data analysis has ruled this crash
is too big to be natural. In some rivers, pink salmon
levels are so low it will take years for the stocks to
recover

Sea lice on salmon skin (Photo courtesy Alexandra Morton)

The alarm was first sounded in 2001 when marine biologist Alexandra Morton, who lives on an island in the archipelago, noticed sea lice infesting juvenile pink salmon. She estimated that 78 percent of her 700 smolt sample were lethally infected, and warned the two levels of government of possible dire consequences. “The fish farms are providing a breeding ground for the lice,” Morton said.

In Alaska, where fish farms are banned, sea lice are not found to prey on juvenile pink salmon.

The aquaculture problems in Canada’s Broughton Archipelago echo those in Norway, Ireland, and Scotland, where the environmental impacts of fish farming have led to large scale collapses of wild salmon populations.

Salmon aquaculture was first introduced in British Columbia in the 1970s, when the warning examples in Europe were not yet obvious. Growing through the 1980s and 1990s, salmon farming has been viewed as a lucrative alternative to a troubled wild salmon
fishing industry.
The British Columbia Liberal Government led by
Premier Gordon Campbell lifted a five year moratorium on
new fish farm licenses in September, over the concerns of
environmentalists about the effects of open net enclosures
used in salmon aquaculture.

Fish farm in the Broughton Archipelago
(Photo courtesy BC Salmon Farmers Association)

The Pacific Fisheries Resource Conservation Council report recommends two possible strategies for managing the risk to this year's pinks. Fraser said, “Where there is a risk of serious or irreversible harm, the precautionary approach calls for action based on the best evidence available. In this case the absence of any evidence of some other causes other than sea lice justifies action.”

The first strategy, preferred by the council, is to allow all salmon farms in the Broughton Archipelago to lie fallow. A temporary removal of all farmed fish from their open net sea pens would have to be completed by the end of February 2003, six weeks before the tiny pink smolts hit the ocean, if the sea lice life cycle is to be broken.

A second strategy, not the preferred one, would be to implement sea lice control measures on the salmon farms, including application of chlorine based pesticides to kill the parasites.