Science Response 2013/022

Review and update of southern BC Chinook conservation unit assignments

Context

Many populations of Chinook salmon (Oncorhynchus tshawytscha) from southern British Columbia, entering the ocean south of Cape Caution, have experienced repeated years of low spawner escapements and there is a high degree of uncertainty about their longer term abundance and productivity.  Fisheries and Oceans Canada (DFO) is currently undertaking several initiatives in order to assess the current status of these stocks and to guide the implementation of appropriate actions for their conservation into the future.  These actions are within the context of both the Wild Salmon Policy (WSP) and upcoming assessment of status by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) (currently scheduled for autumn 2014).

In order to accurately assess the status of salmon stocks under the WSP, methodology was developed to systematically aggregate individual salmon populations into Conservation Units (CUs) (Holtby and Ciruna 2007), hereafter called the “original CU assignments”.  At the time, participants recognized that the CUs identified would need to be regularly modified as new information, analyses and interpretation became available (DFO 2009).  Although the original CU assignments are largely still valid, several inconsistencies and omissions have been noted among southern BC Chinook populations.  In preparation for a pre-COSEWIC data review in March 2013, a thorough review of the southern BC Chinook CU assignments has been conducted, resulting in several suggested revisions.  Subsequently, there is a need to obtain departmental endorsement of these changes and to disseminate the new information so that it will be reflected in all DFO resources that contain the CU assignments (e.g., regional databases and spatial mapping utilities).

The original CU assignment process and results can be found in Holtby and Ciruna (2007).

Response Report is the result from the Science Special Response Process of February 6, 2013 on the review and update of southern BC Chinook conservation unit assignments.

Complete document (PDF, 387 KB)

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