Mark-recapture experiments were conducted to estimate abundance of male lake trout Salvelinus namaycush on sampled spawning grounds and their survival rates and recruitment in Paxson Lake in the Copper River drainage and Lake Louise in the Susitna River drainage. Maximum sustainable yields and carrying capacities of populations in Paxson Lake, Lake Louise and Susitna Lake were estimated with thermal habitat volume (THV) measurements: the average volume of water between 8 and 12C. The mark-recapture experiment conducted at Paxson Lake in 1995 generated an estimate of abundance for 1994 of 2,438 (SE = 94) male lake trout on the sampled spawning beds. An estimated 1,857 (SE = 88) males were present on the sampled spawning beds of Lake Louise in 1995. Estimated maximum sustainable yield of lake trout from Paxson Lake is 0.89 kg ha-1 y-1, 0.93 kg ha-1 y-1 from Lake Louise and 0.98 kg ha-1 y-1 for Susitna Lake. Current harvests from all three lakes are below these levels.