Whitefish, Coregonus lavaretus (L.), in the fisheries management of Lake Goldopiwo (Northeastern Poland) from 1950 to 2005

The growth rate of whitefish, Coregonus lavaretus (L.), in Lake Goldopiwo (Mazurian Lake District, Poland) in the 1932-1999 period was studied. The magnitudes of catches and stocking during the 1950-2005 period were also determined. Once the studied population reached the maximum density, the growth rate diminished distinctly but commercial catches remained at a very high level for the subsequent 21 years at an annual mean of 8181 kg, and 9.5 kg/ha. Throughout the entire study period, no significant relationship was noted between the magnitudes of catches and stocking. The cause of the collapse in whitefish exploitation in Lake Goldopiwo must be sought for in disadvantageous changes in the environment and decreasing fisheries exploitation