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COSEWIC assessment and status report on the coho salmon (Interior Fraser population) in Canada

Existing Protection

The legislative framework for fish conservation in Canada was recently reviewed (Anonymous 2001). Canada is a signatory to the international Convention on Biological Diversity, which requires governments to develop legislation and policies to protect ecosystems and habitats and maintain viable species populations. The federal Fisheries Act requires proposed alterations to habitat to be authorized by DFO, although in BC, provincial and municipal governments also regulate many land and water use activities that can affect fish populations. For example, the provincial Water Act governs the allocation of water, water licences, and the regulation of works in streams. The Canada Oceans Act requires that Canada manage its marine resources to conserve biological diversity and natural habitats.

In 1998 DFO released its New Directions Policy for the Pacific region (DFO 1998c). The first two principles in this policy state that conservation of Pacific salmon stocks is the primary objective of Fisheries and Oceans and will take precedence in managing the resource, and that a precautionary approach to fisheries management will continue to be adopted. One of the consequences of the New Directions Policy is the (draft) Wild Salmon Policy (DFO 2000). The primary goal of the Wild Salmon Policy is to promote the long-term viability of Pacific salmon populations and their natural habitat. This policy document is currently being revised and it is expected that it will be completed in 2002.

The rationale for considering interior Fraser coho a nationally significant population was provided earlier.  At the spring 1998 meeting of the PSARC (Pacific Scientific Assessment Review Committee) Salmon Subcommittee, the status of interior Fraser River coho was reviewed (Irvine et al. 1999a), and a risk assessment undertaken (Bradford 1998). The PSARC Steering Committee advised that Thompson River coho were extremely depressed, would continue to decline even in the absence of fishing mortality under current marine survival conditions, and that some populations were at high risk of biological extinction (Stocker and Peacock 1998). On 21 May 1998, David Anderson, Minister of Fisheries and Oceans Canada, announced that “despite significant conservation measures implemented by my department over the last three years, scientific evidence demonstrates conclusively that wild coho stocks are declining and some are at extreme risk”. Minister Anderson proclaimed a conservation objective of achieving zero fishing mortality for critical Thompson (and upper Skeena) coho stocks. It was expected that such restrictions would be required for six to eight years. However, as illustrated in Fig. 9, the time actually required for rebuilding is highly dependant on survival rates.

Regulatory changes made following Minister Anderson’s statements were probably the most significant fishery changes ever implemented within the Pacific Region of Canada (Irvine and Bradford 2000). In the last several years, managers have allocated what was considered to be an acceptable exploitation for Thompson coho in southern BC fisheries (~2%) amongst these fisheries. In 2000, the total exploitation of interior Fraser coho was the lowest on record, only 3.4% (Table 1), which was divided equally between southern BC and the USA (mostly Washington State). A combination of low fishing pressures, and what appear to be increasing although still low marine survivals, may have stopped the declining trend for interior Fraser coho salmon.

There is no consensus within the scientific community about future survival patterns for coho salmon. Since virtually all interior Fraser coho are three years old and there is little genetic exchange among broodlines, a minimum of three consecutive years with strong escapements are necessary to be confident of an improvement in abundance status. For nationally significant populations such as coho from the interior Fraser, an extremely cautious approach to fisheries and habitat management will be necessary to ensure the maintenance of viable populations. In particular, negative habitat impacts need to be prevented, and conservative fishery management measures as in place in recent years need to remain in place.