Aquaculture for all

The Mysterious Disappearance of Fraser River Sockeye

Salmonids Health Biosecurity +7 more

As the fishing season peaks, the waters of British Columbia should be boiling over with sockeye salmon, instead they lie quiet and still, writes Adam Anson, TheFishSite. The disastrous failure of this year's run has led to many angry questions, but like the fish, the answers are proving mysteriously allusive.

Go back four years and the 3.3 million-strong parent generation of these salmon are giving their very last life reserves to race upstream towards their breeding spot. Afterwards, analysts recorded a large number of sockeye smolts, which would thrive over the next two years in the nursery waters of the Georgia Straits before embarking on an epic two year open ocean migration.

Adult sockeye salmon
Auburn University

All indications of physical size and health proved positive at the time, promising large numbers on their return. Using predictive models, Fisheries and Oceans Canada (DFO) announced that an estimated 10.6 million sockeye salmon would return to the Fraser River in 2009.

It was only a few weeks ago when ocean test net catches had been consistently low that the DFO began to revise their estimates. The true, startlingly poor reality of the situation only became apparent when the runs arrived.

So small were the runs in Fraser River that many couldn't believe that they had actually arrived despite knowing that sockeye are renowned for being on time. Taking into consideration recent sockeye counts, the DFO now estimate an overall total of less than 1.7 million sockeye salmon for the course of the year.

The Emerging Problem

“In order to provide a fighting chance for returning sockeye, it is imperative that the Department of Fisheries and Oceans shut down the Chinook sports fishery on the Fraser River," insisted the BC Indian Chiefs early August.

The aborigines themselves had only caught 18,000 sockeye, by comparison with a normal year of 400,000/500,000. But the BC Indian Chiefs were resilient in their message of conservation.

"Every effort, including the complete shut-down of the sports fishery, should be made to limit the possibility of incidental by-catch or the practice of snagging or ‘flossing’ of sockeye. It’s still a grim, grim picture for the Fraser sockeye."

Later, to the disappointment of many an angler, the DOF did shut down the commercial fisheries. In British Columbia there are 400,000 registered anglers contributing $400 million through the license fees of sport fisheries. Commercial boats have also been redundant throughout this time, left tied to the docks to the detriment of fishers, processors, retailers and consumers.

But to most British Columbians the Fraser River sockeye is more than just industry, sport or delicacy, the sockeye is key to their way of life of, providing an essential part of the food chain for the epic creatures that live there - the grizzly bears, the bald eagles and the killer whales that all await its return. Even nutrients from dead salmon play an integral part to local eco-systems.

Searching for Answers

A young smolt struggles with a life threatening sea lice infestation
Watershed Watch

Naturally, one question has risen above all others: "What happened to all the salmon?" Fierce media debate has followed, pitching scientists and industry experts in opposition.

According to the Pacific Salmon Association, the reasons for the very low returns of most Fraser sockeye stocks are presently unknown. However, they do say that some potential factors can be rejected.

"Overfishing and insufficient escapement can be ruled out as large numbers of sockeye reached their spawning areas in 2005 and only a small fraction of the total Fraser sockeye run has been harvested in 2009," says the association.

"Second, freshwater survival egg-to-fry or smolt stage was not a contributing factor in either the Chilko or Quesnel sockeye stocks."

"Third, the warmer than average Fraser River water temperatures in 2009 are also not a factor in the low return of adults in 2009 because the in-season estimates of Fraser sockeye abundance are generated from a combination of marine-area test fisheries and lower Fraser River hydro-acoustic surveys and both of these assessment tools have provided consistent data indicating very low Fraser sockeye abundances."

According to the association, the evidence suggests that factors in the marine environment during the time that the smolts left in 2007 and before they returned in 2009 are likeliest at blame for the poor returns.

However, not everyone is convinced that the problems did not occur inside the river itself. Some point to the hot dry summer which has warmed the mouth of British Columbian rivers, sapping the remaining energy of the salmon early in their upstream runs. Forest companies have also been fingered for warming the temperature of waters in the Riparian, but a more contentious argument revolves around the potential threat of salmon farms.

The Watershed Watch Salmon Society say that the sea lice from recently introduced salmon farms dotted along the rivers of British Columbia are directly causing, or at least heavily contributing to the problem.

"Salmon farms create an unnatural reservoir of sea lice that is especially detrimental to juvenile salmon heading for the ocean simply because of their small size," says the society. "One or two sea lice may be enough to kill a juvenile salmon. Much higher numbers have been observed recently on juvenile pink salmon near BC’s salmon farms."

Despite of the evidence against them, BC Salmon Farmers Association is rejecting any blame.

"Declining wild salmon populations are a concern along the entire Pacific Northwest Coast – both in areas with salmon farms and in areas without salmon farms," stated the association.

"Though ENGOs frequently point to sea lice as a cause of wild salmon declines, these declining populations are also seen in Oregon and California where salmon farming is not practiced and this suggests that other factors are responsible."

According to BC Salmon Farmers Association, farmers contribute $800 million to BC's economy and employ over 6000 people. However, for many, it is this economic factor that lies at the heart of the problem. Giving the DFO, what many deem, the impossible task of promoting salmon aquaculture and protecting wild salmon stocks at the same time.

Wherever the problem lies, concerns are beginning to turn further afield. Other salmon stocks are yet to return to Canada, including the great pink run, estimated at 17 million.

August 2009
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