THE BEHAVIORAL-RESPONSE OF LAKE TROUT TO A LOSS OF TRADITIONAL SPAWNING SITES

We experimentally rested the behavioral response of native lake trout (Salvelinus namaycush) to the loss of spawning habitat in a 67 ha lake . In the first year, two of the historically utilized spawning sites ( 15% of the historic spawning habitat) were covered to prevent spawning fish from using the sites. Lake trout responded by selecting 12 new s ites around the lake. In the second year, when an additional 35% of th e historic spawning habitat was removed, the density of eggs deposited at the remaining traditional site increased and 8 more new sites were selected. These manipulations produced no detectable change in the ti ming of spawning and fish appeared to rapidly abandon efforts to use t he former sites. This study demonstrates that lake trout will actively seek out alternate spawning sites when traditional habitat is lost. I nitial indications are that useable spawning habitat is not limited in Whitepine Lake, but the long-term effects of the selection of alterna tive sites are not yet known.