Population Assessment of Canadian Northern Dolly Varden

Dolly Varden is a culturally important species for Inuvialuit and Gwich’in peoples. There are six confirmed populations of anadromous Dolly Varden in Canada that contribute to a mixed stock fishery along the Beaufort Sea coast. Additionally, harvesting occurs in the Mackenzie River Delta targeting Dolly Varden primarily from the Rat River. With the exception of the Rat River, assessment information for other populations is outdated. With the recent creation of an integrated fisheries management plan for northern form Dolly Varden in Canada we have begun to develop a standardized, comprehensive approach for assessment of these populations. Our approach expands on existing methods used in the Rat River to improve the quality and utility of the data. We are conducting multiple mark-recapture studies where fish are tagged during the fall at spawning/overwintering areas over two consecutive years and recaptured the following year at the same location allowing us to obtain multiple abundance estimates, survival and mortality rates, along with information on growth, movements and maturity cycles. Biological data collected during tagging studies include length, sex and maturity. Additionally, DIDSON sonar is being used to enumerate populations concurrently with mark-recapture events to help validate abundance estimation methods, and obtain information on the return migration. Future assessments will continue using data collected from existing harvest-based monitoring programs and a new program to obtain catch and biological information along the Beaufort Sea coast. Results from research activities in the Rat, Big Fish and Babbage rivers in 2009 and 2010 are presented.