Fully protected safe havens would have positive effect on ecosystems
By Chris Darimont and Misty MacDuffee
The headlines blare across local, regional, and national media: Nine million Fraser River sockeye salmon missing. At the same time, questions have arisen concerning the status of other Pacific salmon runs on B.C.’s central and north coast, a region known as the Great Bear Rainforest. Many have asked how these potential declines are affecting coastal bears, which depend on salmon for sustenance.
With both acknowledged and possible calamities as compelling and urgent catalysts, Raincoast Conservation Foundation is advocating for British Columbia’s first fully protected salmon runs. This means creation of safe havens or sanctuaries that protect salmon from marine fisheries on their ocean migration routes and also protect their freshwater spawning habitat.
This bold and ambitious proposal runs contrary to the historical philosophical underpinnings of salmon management.
After all, fisheries managers have always assumed that salmon exist exclusively for human consumption. Consequently, runs are only protected from harvest when they are endangered. But how has such status quo management served salmon and the terrestrial ecosystems they nourish?
Not well. Even runs that spawn in protected areas are subject to exploitation by fisheries at levels as high as 80 per cent. Put yourself in the paws of bears. Imagine if your annual paycheque was reduced by four-fifths.
Then imagine the effect on the coastal food web economy. The subsidy presented to the forest and its inhabitants by bears, which leave portions of salmon carcasses behind, is also greatly diminished. Accordingly, we believe that protected areas that host highly exploited salmon runs are not truly protected, because a major ecological process is compromised.
Of course, it’s not just fishing nets that rob bears and other coastal life of this bonanza. Fish farms, climate change, habitat loss, fresh water withdrawals, changing ocean conditions and more all influence salmon abundance.
Many of these impacts are hard to predict, are indirectly related to salmon abundance or require complex solutions.
As eminent U.S. fisheries scientist Robert Lackey has stated, ‘our collective actions — from the rules of commerce to philosophies of growth and development — are not fish-friendly and tend to put relentless downward pressure on salmon numbers.’
In contrast to combating other threats, reducing or eliminating exploitation– on at least some runs — is straightforward and would have an immediate and direct positive effect on coastal ecosystems.
The best thinking in conservation science confirms that sustainable salmon management must include consideration for terrestrial organisms that have co-evolved with, depend on and help sustain salmon.
Indeed, Fisheries and Oceans Canada’s new wild salmon policy provides an important conservation opportunity as it identifies the need for management to transcend salmon production alone, explicitly seeking information on how much salmon is required to sustain key terrestrial species.
Research being conducted by Raincoast’s scientists, in conjunction with major universities, directly addresses this question for an important group of terrestrial salmon users — the large carnivores.
It is a matter of competition, and the odds are stacked against carnivores in these coastal “salmon forests.” Simply put, commercial, recreational and subsistence fishermen engage in what ecologists call exploitative competition — they capture salmon en route to spawning grounds before they even become available to awaiting carnivores.
As a result, we suspect that grizzly bears, in particular, receive a fraction of the salmon they are used to, which ultimately results in population declines. Not by die-offs as others have speculated, but through repeated years of low birth rates. Grizzlies are omnivorous and can persist even without salmon, but they have far fewer offspring.
Our current research — all conducted from non-invasively sampled bear hair– provides timely insight into these concerns. We are estimating how much salmon coastal grizzlies are consuming, tracking bear numbers and determining the relationship between salmon and bear numbers. Hormonal assays give us information about potential stress, reproductive activity and protein deprivation bears might show in response to poor salmon returns.
From such knowledge emerges a solid basis for action. Experience tells us that only carefully gathered information and prudent inference can provide the arguments that form the foundation for lasting changes to management of coastal systems.
Chris Darimont is a post-doctoral fellow at the University of California -Santa Cruz and Misty MacDuffee is a biologist with the Raincoast Conservation Foundation.
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