Patrick Moore, Financial Post
Anti-aquaculture activist Alexandra Morton is well known for her claims that salmon farms are infecting wild salmon with sea lice.
Those claims continue to remain questionable, despite misleading media coverage of a recent decision by the B.C. Special Prosecutor not to prosecute federal and provincial authorities for allegations Ms. Morton raised about salmon farms.
These commentators suggest Ms. Morton has been vindicated by the prosecutor and that her many critics, including myself, are simply in the wrong. Nothing could be further from the truth.
First, the prosecutor carefully examined the law and decided not to prosecute because he recognized B.C. salmon farms are in full compliance with federal and provincial regulations. Yet these stories seek to minimize the salmon farms’ total compliance with the law.
Second, the news items fail to report the full details of Frederick Whoriskey’s report, which the prosecutor relied upon to make his decision.
Mr. Whoriskey’s report actually questions Ms. Morton’s attempts to link salmon farms with sea lice infestations in a number of areas.
For example, his report is critical of Ms. Morton’s dip net methodology, which tends to select sick and dying fish that float to the water’s surface, noting it “may have biased the sampling towards infected fish.”
Mr. Whoriskey also notes Ms. Morton’s research failed to control for certain variables and consequently left open the question of whether “the source of many of the lice was a marine fish species other than a salmonid that happened to be resident in the vicinity of the farm at the time of the work.”
Mr. Whoriskey identifies further flaws in Ms. Morton’s work, highlighting the fact that in one of her experiments, “the experimental enclosures most probably stressed the fish and affected their feeding behaviour, both of which could have aggravated mortality.”
As Mr. Whoriskey writes, “it is more difficult to attribute the declines in pink salmon returns to the Broughton Archipelago, to the single cause of sea lice infestations. Other factors could be acting independently or synergistically of lice to contribute to mortalities.”
Mr. Whoriskey cautions “pink salmon populations have historically fluctuated, sometimes on an immense scale. By chance, we could be in one such cycle.”
Most important, while Mr. Whoriskey might agree with some of Ms. Morton’s correlations, he is careful in noting that such correlative evidence, on its own, cannot imply “cause and effect.”
Read in its full context, then, this report highlights the flaws in Ms. Morton’s work and simply confirms what many experts have always said: There is no scientific evidence demonstrating a causal link between sea lice infestations and salmon farms.
Recent stories claiming Ms. Morton has been vindicated report none of this.
Yet the idea that salmon farms are unrelated to sea lice infestations of wild fish is not surprising.
Looking at the data for salmon returns in the Broughton Archipelago (the area of B.C.’s central coast where Ms. Morton concentrates her attack on salmon farms) over the past half-century shows how little impact salmon farms have had on wild salmon.
Activists such as Ms. Morton often point to 2002, arguing that in that year salmon returns crashed as a result of sea lice infestations coming from salmon farms. They fail to acknowledge, however, that the previous two years saw the largest pink salmon returns in recorded history. In fact, average annual returns of pink salmon have been higher during the 15 years since salmon farming began in the Broughton than they were during the previous 35 years.
It is not surprising that the salmon population plunged in 2002. Booms and busts are common in nature. Many scientists now believe the large populations of the previous two years simply ate themselves out of house and home, resulting in a crash that had absolutely nothing to do with salmon farms.
For all Ms. Morton’s claims about the negative impact of salmon farms on wild salmon, the largest returns of wild salmon in recorded history came at a time when salmon farms were well established in the area. If farms were really affecting wild salmon to such a negative degree, why did we see such historically large returns in 2000 and 2001?
Furthermore, the 2002 crash was not the lowest return of wild salmon recorded in the Broughton. In a number of years before salmon farms existed on the coast, the pink populations were even lower than in the crash year of 2002.
Since 2002, returns of wild salmon in the Broughton have continued to increase, rising from 145,000 in that year to 895,000 in 2004. Meanwhile, Ms. Morton continues her tired mantra that she is “witnessing the extinction of a species.” In all likelihood, the salmon are simply recovering from a natural fluctuation that would have occurred with or without salmon farms in the region.