Michigan Department of Natural Resources
Fisheries Research Report No.1884, 1980
Collecting Gear for Lake Trout Eggs and Fry
Thomas M. Stauffer
Abstract.-Gear were developed to sample eggs and fry of lake trout planted in the Great Lakes. Various types of gear were tested in Presque Idle Harbor in Lake Superior near Marquette and in Grand Traverse Bay, Lake Michigan during 1973-1979. Pails set in spawning substrate before lake trout spawned, and lifted after spawning, were used to estimate number of eggs deposited. Fry production was also estimated by leaving the pails until spring when traps installed on the top of the pails caught fry that hatched from eggs previously deposited in the pails. Centrifugal pumps, which sucked up water and organisms from the bottom, were effective in sampling eggs and sac fry on spawning areas. Pyramidal wire-mesh traps, set on lake trout spawning areas, were very effective in catching fry in May and June. Plastic minnow traps also caught fry on spawning areas. A 1. 2-m beam trawl with "ticklers"' was moderately effective for fry on rough-bottomed spawning areas and on smooth, hard bottom nearby during May-July. On moderately smooth bottom, a 5-m otter trawl was very effective for fry at night in June and July.