Mark-recapture and catch sampling 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 and Susitna Lake 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 12#C. The mark-recapture experiment conducted at Paxson Lake in 1993 generated an estimate of abundance for 1992 of 2,190 (SE = 164) mature male lake trout on the sampled spawning beds, a decrease from 1991 levels. An estimated 1,392 (SE = 97) mature males were present on the sampled spawning beds of Lake Louise in 1992. The estimate of mature lake trout in Paxson Lake for 1992 was 19,388 (SE = 8,175), an increase over 1991 levels. During spring sampling, lake trout which spawned in Susitna Lake were found to mix completely with fish which spawned in Lake Louise. Therefore, a combined estimate of the abundance of mature lake trout in both lakes was 15,804 (SE = 6,140), an increase from 1991. Strong year classes are present in harvest samples from Paxson Lake from spawning which occurred in 1981 and 1986. Lake trout in harvest samples from Lake Louise and Susitna Lake were older and larger than lake trout harvested from Paxson Lake. The maximum sustainable yield of lake trout from Paxson Lake was 0.91 kg ha-1 y-1, 0.86 kg ha-1 y-1 from Lake Louise and 0.73 kg ha-1 y-1 for Susitna Lake. Current harvests from Paxson Lake continue to exceed sustainable levels while harvests from Lake Louise and Susitna Lake are below sustainable yields.