http://worldcat.org/entity/work/id/145199196

Review of population trends in length and age of lake whitefish (Coregonus clulpeoformis) harvested from Great Slave Lake between 1972 and 1995

Commercial fisheries can be responsible for substantial changes in fish populations. Typically, average fish size and age in the catch decline as the fishery progresses. We present evidence of a contrary trend for the Great Slave Lake lake whitefish, Coregonus clupeaformis, fishery between 1972 and 1995. Average length of fish caught increased from 377 mm to 425 mm during this period. Average age of fish caught increased from 7.7 to 10.6 years during 1972 to 1994. Analysis of covariance of length by year with age as a covariate was highly significant (p = 0.0001) suggesting that the increase in length during the study period was independent of the increase in age of fish in the catch. Trend analysis of six administrative areas of Great Slave Lake employed by fishery management showed that increases in size and age occurred in all areas except age in area 1W, suggesting that fishery management was highly effective during this time. The positive and significant regression slopes from the trend analysis indicate that the fishery could have remained stable at even higher exploitation rates. It appears that the management actions of that period of quota and spatial structuring by administrative areas was able to sustain the fishery and perhaps improve fishing conditions in the manner expected by fisheries theory. We examine this possibility and alternative explanations for the observations such as sampling error and environmental change.

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