Redefining Walrus Stocks in Canada
Keywords:walrus, Odobenus rosmarus, satellite tag, genetic, isotope, contaminant
Defining management units is basic to the sound management of resources. Walrus (Odobenus rosmarus rosmarus) are hunted throughout their range in Canada and are subject to other human activities requiring management decisions. Current management units are based on a comprehensive review and a stock assessment completed in the mid 1990s. Between 1993 and 2004, satellite-linked radio tags provided information on the movements of walrus in Canada’s High Arctic. These data were incorporated with other information that has become available since 1995 to reassess walrus management units in Canada. Tagging data and other information suggest that some finer discrimination of walrus populations is needed as a precautionary approach and to formulate testable hypotheses. Specifically, the previous North Water/Baffin Bay walrus stock may be considered to be three stocks: Baffin Bay, west Jones Sound, and Penny Strait Lancaster Sound stocks. The Foxe Basin population appears to comprise two stocks (North Foxe Basin and Central Foxe Basin) rather than one. Previously suspected subdivisions in the Hudson Bay-Davis Strait population are substantiated by isotopic evidence although sampling on a finer geographic scale is required before this stock can be partitioned. There is new evidence to support the previously postulated separation of the walrus in the Southern and Eastern Hudson Bay stock from all others, but no evidence to warrant subdivision.