Science Advisory Report 2015/042
Assessment of Lake Whitefish Status in Great Slave Lake, Northwest Territories, Canada, 1972-2004
- Lake Whitefish is ecologically, culturally and economically important in the Northwest Territories, Canada. A fishery-dependent sampling program was initiated in 1972 to collect biological data including scale age, fork length and dressed weight from all fished areas. The objectives of this study are to profile the spatiotemporal variations in biological characteristics and the potential association with cumulative impacts from localized hydrology, meteorology, and global climate changes during 1972-2004.
- Applying multi-model inference (MMI), a conventional linear regression model did not support the log-transformed pairs of fork length and round weight. Instead, the morphological relationships between log-transformed pairs of fork length and round weight were best described by a piece-wise regression model for fish in southern shallow areas and a cubic model for deep-water fish. The relative condition index, KLC, was used to better reflect the effects of changing mesh sizes and fishing effort.
- The generalized growth model delineated length-at-age growth patterns and indicated that the growth traits of the fish changed along a southwest to northeast gradient in the lake.
- Commercial fisheries on Great Slave Lake commenced in the mid-1940s. The profound variation in Lake Whitefish population biological characteristics and the fishery yields corresponded to changes in social and economic factors. There was no indication of a decline in Lake Whitefish stock status among management areas. However, information gaps and uncertainties in the assessment were identified and further analyses recommended combining fishery-dependent and fishery-independent survey results.
This Science Advisory Report is from the January 26-27, 2011 Regional Advisory Meeting on The Status of Lake Whitefish (Coregonus clupeaformis) in Great Slave Lake. Additional publications from this meeting will be posted on the DFO Science Advisory Schedule as they become available.
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