Mark-recapture experiments were conducted to estimate the abundance, survival rates and recruitment to lake trout Salvelinus namaycush populations 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 and Lake Louise were estimated with thermal habitat volume (THV) measurements: the average volume of water between 8 and 12 C. The mark-recapture experiment conducted at Paxson Lake in 1994 generated an estimate of abundance for 1993 of 2,262 (SE = 126) mature male lake trout on the sampled spawning beds, an increase from 1992 levels. An estimated 2,077 (SE = 112) mature males were present on the sampled spawning beds of Lake Louise in 1993. The number of mature lake trout in Paxson Lake in 1993, estimated from hook and line sampling, was of 45,427 (SE = 22,148), an increase over 1992 levels. The maximum sustainable yield of lake trout from Paxson Lake was 0.92 kg ha-1 y-1, 0.89 kg ha-1 y-1 from Lake Louise, and 0.73 kg ha-1 y-1 for Susitna Lake. The current harvest from Paxson Lake is near estimates of sustainable yield while the harvest from Lake Louise is below sustainable levels.