Article
Salmonine Consumption and Competition for Endemic Prey Fishes in Bear Lake, Utah–Idaho
Transactions of the American Fisheries Society
(2001)
Abstract
Two principal sport fish—the indigenous Bonneville cutthroat trout Oncorhynchus clarki utah and the introduced lake trout Salvelinus namaycush—are the dominant piscivores in Bear Lake, a 282-km2oligotrophic system. These piscivores rely predominantly on four endemic prey fish species that make up a major portion of the unique Bear Lake fish assemblage. We estimated the annual biomass of pelagic and benthic prey fish by using hydroacoustic and trawling techniques. We also estimated the lakewide abundance of piscivores with a multiple mark–recapture survey and used a bioenergetics model to compare the population-level consumption of prey fish with prey fish production. Prey fish biomass declined to a minimum during 1991 and 1992 but subsequently recovered to reach maximum levels during 1994 and 1995. The proportion of maximum ration estimates from model simulations indicated that the piscivores were consuming well below maximum rations during a period when predation exceeded prey fish production, thereby providing the potential for a predator–prey imbalance. Predation impacts by lake trout cohorts were prolonged because of high survivorship and long life expectancy. Although cutthroat trout outnumbered lake trout, the larger, more piscivorous size-classes of cutthroat trout accounted for only 12.5% of their population.
Disciplines
Publication Date
2001
DOI
https://doi.org/10.1577/1548-8659(2001)130%3C1175:SCACFE%3E2.0.CO;2
Citation Information
Wayne A. Wurtsbaugh. "Salmonine Consumption and Competition for Endemic Prey Fishes in Bear Lake, Utah–Idaho" Transactions of the American Fisheries Society Vol. 130 Iss. 6 (2001) p. 1175 - 1189 Available at: http://works.bepress.com/wayne_wurtsbaugh/237/