Spare a Thought for the Pink Salmon

Jeremy Brown is a commercial fisher from Bellingham. He is a board member of the Washington Trollers Association, the Western Fishboat Owners Association, the American Fishermens Research Foundation and the Nooksack Salmon Enhancement Association. He is a 2002 Food and Society Policy Fellow, a program of the Thomas Jefferson Agricultural Institute in partnership with the Institute for Agriculture and Trade Policy and funded by the W.K. Kellogg Foundation.

Pink salmon get little respect, they are too easy to catch and lack the manly bravado of the greater game fish, and being mild and delicate, are valued less by fish buyers. Yet the ecology of all Pacific salmon species in our region is interconnected with that of the lowly pink, and what threatens the survival of pinks today, may threaten all in the near future.

Something is going wrong with the wild pink salmon runs in Canada’s Broughton Archipelago (see map on page 10). Improved ocean conditions and careful fisheries management have generally produced very robust returns of salmon to streams along the British Columbia Coast, even in areas immediately adjacent to the Broughton, yet stocks in this one area continue to spiral downward.

Pink salmon (Oncorhynchus gorbuscha) has a strictly two-year life cycle; so any particular stock is comprised of an even-year and odd-year cycle, with negligible interchange between the two. Thus an incident that effects spawning productivity in 2002 would be reflected in the size of the returning run in 2004 but not in 2003 or 2005, and so on.

Spawning and migration conditions in the Broughton Archipelago had been severely impacted by logging in the 1940s and 50s, but by the late 90s returns had rebuilt to exceed any previously recorded for both odd and even year classes.

Then in 2002 and 2003 the runs collapsed. From 3.6 million in 2000, the 2002 run came in at 147,000, and from 1.5 million in 2001, the odd-year class came back at just 188,000 in 2003.

There has been no shortage of earnest enquiry into the cause of this collapse. The Canadian Department of Fisheries and Oceans (DFO), the federal agency with principle responsibility for salmon, has poured resources into sampling and data gathering.

One condition particular to the Broughton region is a concentration of salmon farms (see map on page 10). These have long experienced trouble with the naturally occurring sea lice (Lepeophtheirus salmonis) and it was noticed that outmigrating smolts in preceding years had been progressively more infected with sea lice, something that generally they do not acquire until much later in life.

Once sea lice gain a foothold in a farm they are all but impossible to eradicate. Standard management practices call for the aggressive application of the potent pesticides Ivermectin or Slice,1 which can reduce but rarely eliminate the problem. Sea lice can rapidly become quite tolerant to treatment, but since only fallowing will eliminate the problem, farm managers will tolerate infestations as long as they can.

While keeping farm infestations to one or two lice per adult fish in the pen is a ‘tolerable’ level, that represents several hundred thousand sea lice in a very confined area. Sea lice are evolved to travel on migrating fish, they release free swimming copepodid stage larvae that will attach to any fish they encounter, so a dense static host population greatly enhances their natural productivity.

Residents of the Broughton area had remarked on particularly high—frequently lethal—levels of sea lice on outmigrating pink salmon in 2001, the year class from the record 2000 brood year that would return, presumably in similar high numbers, in 2002.

Alerted to this, in 2001 DFO conducted seine and trawl surveys in the area to sample for sea lice on outmigrating salmon smolts. These efforts subsequently were increased and continue presently. To the surprise of all, however, DFO was unable to establish a link, announcing last October that they were “astounded” that of 11,700 samples gathered, not one suffered from sores or hemorrhaging that could be attributed to sea lice.

Dr. Richard Beamish, head of the Pacific Biological Station in Nanaimo that did the work, speculated that there might possibly be an overwintering stage of the sea lice life history that remains totally undiscovered (sic), and therefore would conveniently excuse DFO’s inability to explain what other researchers were finding.2

Marine biologist Alexandra Morton, perhaps best known in Bellingham as author of the acclaimed book “Listening to Whales,” has conducted extensive independent research throughout the British Columbia coast and reached her own conclusions.3 Morton found 90 percent of the juvenile chum and pink salmon gathered in some areas to be infected with lethal sea lice loads, whereas in other areas the frequency was near zero.

It is perhaps rather easy to conclude, therefore, that both researchers were hoping to prove a particular point, and therefore conducted their research with that in mind.

With the resources of a government department at their disposal, DFO chartered two large fishing boats and swept extensive areas with both seine and trawl nets, generally regarded for their ability to scoop whatever is there. Morton, on a very limited budget relied more on resources to hand, a beach seine at some sites, but mostly individually sampling with a hand held dip net. In their first sampling efforts, DFO made 49 trawl tows and 25 seine sets, yet recovered only seven pink salmon smolts.

In subsequent gathering they were more successful, but pink smolts still made up only a fraction of the 11,700 salmon collected. Morton’s more selective methods yielded 2,090 pink and chum smolts.

DFO concluded there was no link between the presence of sea lice on wild salmon and the proximity of salmon farms, that juvenile salmon were largely unaffected and speculated wild salmon from as far away as Washington state might be a vector. What DFO conveniently overlooked was that the farm sites near which they sampled had been recently fallowed by their operator, partially to eliminate sea lice but also because of an outbreak of infectious haemorhagic necrosis (IHN) that had swept through their facilities.

Morton, by contrast, found eightfold higher juvenile infection rates in proximity to salmon farms compared with control sites, and observed that “sustained dominance of juvenile sea lice life stages indicates that infective events were continuous and local.”

While it is possible that both might be equally, partially right, there is a large body of research that would support Morton’s conclusions. DFO simply missed the evidence that was there, and Beamish grasped at straws to cover both the shoddy work and his political bosses’ cronies.4

“DFO claims to care about the future of wild salmon on our coast, but they have allowed more farms than ever to operate in this area, and the sea lice levels are the worst I have seen in four years,” said Ms. Morton. “What is happening here is a tragedy. I am watching the extinction of a species as I conduct my research, but DFO is allowing the salmon farming industry to operate as usual.”

While scientists argue over statistical inferences, and the powers that be plan for further industrialization of the coastline, pink salmon returns to the Broughton continue to plummet. Sea lice infestations persist throughout the region, and pink salmon returns to local streams decline further.

On May 17, 2004, Alexandra Morton reported, “It is carnage out here ... worst I have seen yet.”

Extinction comes in several forms, first ‘commercial extinction’ where there remain too few of a species to harvest. The ‘extirpation’ or local extinction of a species from a portion of its natural range. Biological extinction is the end of the line. Finis.

Broughton pinks are already commercially extinct—there has been little fishing since 2000. Extirpation is close, and depending on the degree to which the Broughton pink stocks are uniquely adapted to their environment, and whether neighboring stocks share enough of those features to adequately adapt, then biological extinction may indeed be taking place, as we watch.

As has been famously observed, species do go extinct all the time, but rarely can the processes be so visible and apparent. Accidental extinction through the agency of man is a sad measure of our stupidity and carelessness. To watch, record and document the process of extinction, and to publicly wash one’s hands as DFO is now doing, is a crime. §