BC Salmon Conservation Units - Version 2 (May 2008)

The first of six strategies in Canada’s Policy for the Conservation of Wild Pacific Salmon concerns the identification of units of diversity (called Conservation Units) and determining their conservation status. The primary purpose of this document is to describe the method that was developed to identify the Conservation Units for the five species of Pacific salmon in British Columbia. The description of units in most of the Yukon and Northwest Territories will proceed using this method once the ecotypology of those areas is completed.The approach of Waples et al. (2005, Journal of Fish Biology, volume 59, pages 1-41) was modified to characterize diversity in Pacific salmon along three major axes: ecology, life history, and molecular genetics, and then to compartmentalize that diversity into Conservation Units. The three descriptive axes are used to map local adaptation in a variety of ways. The maps are then examined and combined to locate and describe the Conservation Units. The first stage in the description of the Conservation Units is based solely on ecology. The ecotypologies used include a characterization of the near-shore marine environment in addition to one for fresh water. The ecotypological analysis partitioned British Columbia into Joint Adaptive Zones. Our hypothesis is that salmon are significantly more ecologically interchangeable within an adaptive zone than between zones. Absent any other information, the adaptive zones would define the Conservation Units. In most cases considerably more information was available to be considered in the second stage of the description. That stages involves the use of life history, molecular genetics, and further ecological characterizations to group and partition the first stage units into the final Conservation Units. The result is Conservation Units that are described through the joint application of all three axes.The method and its application to Pacific salmon in British Columbia is described in Holtby and Ciruna (2007, CSAS Research Document 2007/070).