BROOK TROUT (SALVELINUS-FONTINALIS) EMBRYO HABITAT AND TIMING OF ALEVIN EMERGENCE IN A LAKE AND A STREAM

We assessed redd characteristics of brook trout in a lake and a stream and alevin emergence in the lake. Both populations spawned over upwelling groundwater. In the lake site fish deposited eggs 7-19 cm in the sediment in an egg pocket that contained large-particle substrate. A similar vertical distribution of eggs (16-20 cm) and substrate occurred in the stream; however, in addition to the digging action of the female, the flow conditions in the stream appeared to produce coarser surface sediment conditions. Groundwater offered a high concentration of dissolved oxygen and, relative to lake water, less variable temperature and pH regimes for incubating eggs. Alevin emergence extended over a 71-day period, coinciding with the spring thaw and an episodic pH depression.