Growth and relative survival of progeny developed from rainbow trout brood fish inhabiting coarse fish environments and progeny from rainbow trout brood fish from a monoculture lake were compared in eight coarsefish lakes. The study was conducted using Blackwater River and Tsuniah, Bootjack and Tzenzaicut lakes strains (coarsefish trout strains) and the Pennask Lake strain (monoculture strain) in lakes with one or more species of coarsescale sucker, longnose sucker, redside shiner, peamouth chub, and northern squawfish. For three consecutive years, a combination of two coarsefish rainbow trout strains plus the Pennask strain were stocked as one-year-old fish into the study lakes in May, and first sampled with gillnets after a five month period.
Growth of the coarsefish strains of rainbow trout at age 1+ was better than that of the Pennask monoculture strain. The 1991 broodyear of Blackwater fish weighed significantly more than Pennask fish in all four lakes where both strains were stocked. The Tzenzaicut strain was significantly greater in length than Pennask in three of five lakes stocked. The Tsuniah Lake rainbow trout strain was significantly heavier, but not greater in length, than Pennask strain fish in two of three lakes in which these strains were stocked. Bootjack progeny were significantly greater in length than Pennask fish in only one of the four lakes in which both were stocked. At age 2+, the Pennask strain was never significantly larger, in length or weight, than any of the coarsefish trout strains to which they were compared.
Relative survival to age 1+, compared to Pennask, was significantly higher for the Tzenzaicut strain in four out of five lakes. Blackwater, Tsuniah, and Bootjack fish were caught in greater numbers than Pennask in only one lake. Relative survival trends to age 2+ was similar to that of the age 1+ fish.
Incidence of precocious males ...
Godin, Theresa I., Tsumura, Kanji. 1993. Rainbow Trout Broodstocks for Coarsefish Lakes: Habitat Conservation Fund Progress Report (1992-93). Ministry of Environment, Lands and Parks. Fisheries Project Report. RD34