This report summarizes the progress and activities for the third year of a Habitat Conservation Fund project investigating the survival of alkaline strain rainbow trout from Stump and Green lakes, as well as survival of kokanee in alkaline lakes. In a preliminary comparison, progeny from three non-alkaline rainbow trout lakes strains - Pennask, Tzenzaicut, and Bootjack - were stocked at age 1 into Lake 5567 in 1991. Cumulative samples, collected over three years, indicates survival to be 30% of the total number released for each strain. In 1992 and 1993, Lake 5567 received stockings of one-year-old rainbow trout progeny from Stump and Green and Pennask lakes brood fish. After two years, cumulative catches were 30% of the original number released for the alkaline strains compared to 18% for the non-alkaline Pennask strain for the 1992 releases. For the 1993 release, Green Lake rainbow trout were caught in greater numbers than either the Stump or Pennask strains, after one sampling period. In short term survival studies, Pennask strain rainbow trout held in alkaline water from Till Lake resulted in a mortality rate of 60% after 60 hours. Kokanee survival tested in net pens in alkaline Stump Lake resulted in an average mortality rate of 44% after three days. Brood fish from Stump and Green lakes were collected in 1993, for the third consecutive year. Progeny from these fish will be stocked into alkaline study lakes, Lake 5567 and Till Lake, in the spring of 1994. The relative survival and growth characteristics of alkaline lake progeny will then be compared to progeny of non-alkaline Pennask Lake brood fish over three brood years and age classes in Lake 5567.
Toth, Brian M., Tsumura, Kanji. 1994. Alkaline Lakes Enhancement: Habitat Conservation Fund Progress Report (1993-94). Ministry of Environment, Lands and Parks. Fisheries Project Report. RD38