Backgrounder: More Fraser sockeye populations in trouble than previously thought

Posted by Trish Hall on

BACKGROUNDER

Evaluating the status of BC’s wild salmon populations

One of the main objectives of Canada’s Policy for the Conservation of Wild Pacific Salmon, released in 2005, is to “safeguard the genetic diversity of wild Pacific salmon”. The policy states that the federal Department of Fisheries and Oceans (DFO) “intends to maintain diversity through the protection of ‘Conservation Units’ (CUs).” These are populations of salmon that government scientists have determined are genetically unique and irreplaceable. A smaller CU, such as Pitt River sockeye, may contain dozens of individual spawning populations, while a larger CU, such as Fraser River pink salmon, will contain hundreds. To protect salmon CUs, the Wild Salmon Policy (WSP) requires that they be maintained above a “lower benchmark” – a level of abundance below which a salmon population will require significant management intervention for recovery. The “lower benchmark” is also designed to avoid having CUs listed as threatened or endangered under the Species At Risk Act.

DFO retreats from fully evaluating Fraser sockeye

Six years after the introduction of the Wild Salmon Policy, DFO has not finalized benchmarks or determined the status of a single salmon CU. The first status assessment under the WSP – for Fraser River sockeye salmon – was to be contained in a draft report recently entered into evidence at the Commission of Inquiry into the Decline of Sockeye Salmon in the Fraser River, otherwise known as the Cohen Commission. An earlier draft of the report was titled Fraser Sockeye Wild Salmon Policy Evaluation of Stock Status: State and Rate. However, the report fell short of actually assigning benchmarks and status determinations for Fraser sockeye, a shortcoming that is reflected in the 181-page report’s revised title: Evaluation of Uncertainty in Fraser Sockeye Wild Salmon Policy Status using Abundance and Trends in Abundance Metrics.

Fraser River sockeye salmon

At 240,000 km2 the Fraser is B.C.’s largest watershed, draining one quarter of the province, an area the size of California. Despite the damage done by more than a century of overfishing in mixed-stock marine fisheries, the Fraser River is still home to the largest number of distinct sockeye salmon populations (CUs) of any watershed on earth. The sockeye returns are highly variable, with larger returns occurring once every four years. Sockeye returns to the Fraser from 2007-2009 were some of the lowest on record, leading to the formation of the Cohen Commission. In 2010, for reasons that are not yet clear, Fraser River sockeye had their highest return since 1913, prior to which such large returns were routine.

While some Fraser sockeye populations are holding their own – like the Adams River population that made up the bulk of last year’s large return – many others are not. In their 2008 Red-List Report on sockeye salmon, the International Union for the Conservation of Nature (IUCN) classified various populations of Fraser sockeye as “vulnerable”, “endangered” and “critically endangered”, with a few being of “least concern”.

Despite the large number of Fraser sockeye populations that now appear to be in the “red zone”, only one – Cultus Lake sockeye – has been identified as endangered by the federal government, although it was rejected for legal protection under the Species At Risk Act.

Conservationists are calling on the Department of Fisheries and Oceans to immediately complete the urgent task of assigning official red-yellow-green status to all Fraser sockeye populations, so that recovery planning can be initiated for all Fraser sockeye populations in the “red zone”. Recovery plans must identify and mitigate human threats to salmon populations, including overfishing, habitat destruction and fish farms, say scientists with the Watershed Watch Salmon Society, David Suzuki Foundation, SkeenaWild Conservation Trust and Raincoast Conservation Foundation.

The importance of maintaining diverse and abundant salmon populations

Recovering depleted salmon populations will likely bring economic benefits. A landmark 2010 study by fisheries scientists at the University of Washington showed that in places where managers have maintained a diverse “portfolio” of salmon populations, overall abundance remained high from year to year, resulting in more frequent fishing opportunities and economic stability for the fishing industry. The principle is similar to that of a diverse portfolio of financial investments allowing for stable returns under various economic conditions. Different salmon populations have evolved to thrive under different sets of environmental conditions, so conditions on any given year will favour some populations but not others.