Equilibrium Yield and Management of Cutthroat Trout in Yellowstone Lake
Equilibrium Yield and Management of Cutthroat Trout in Yellowstone Lake

Author: Norman Gustaf Benson

Publisher:

Published: 1963

Total Pages: 52

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Equilibrium yield of the cutthroat trout, Salmo clarki lewisi Girard, in Yellowstone Lake, Wyo., is determined from data on catch and spawning runs from 1945 to 1961. Changes in growth rate, spawning runs, mortality rates, and year-class strength are related to differences in total catch. Three stages of exploitation of the stock are defined and the maximum safe catch or equilibrium yield is estimated at 325,000 trout. Management of the sport fishery according to equilibrium yield is discussed with reference to regulations, distribution of fishing pressure, planting, and interspecific competition. The Yellowstone River fishery is treated briefly.

Fluctuations in Age Composition and Growth Rate of Cutthroat Trout in Yellowstone Lake
Fluctuations in Age Composition and Growth Rate of Cutthroat Trout in Yellowstone Lake

Author: Ross V. Bulkley

Publisher:

Published: 1961

Total Pages: 40

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Age composition, growth rate, and year-class strength of Yellowstone Lake cutthroat trout from collections made in 1948 and from 1950 to 1959 are analyzed to relate total catch changes in age composition and growth rate. An increase in growth rate of fish fully recruited to the fishery and a decrease in percentages of fish belonging to age groups VI and VII are attributed to an increase in fishing pressure. Mean age of the catch varied with year-length of the catch has remained high, suggesting that production is more efficient now than in past years. Maximum equilibrium yield may be near. If the catch continues to increase at the present rate, it may become excessive within the next few years.

Ecology of Daphnia in Bull Shoals Reservoir
Ecology of Daphnia in Bull Shoals Reservoir

Author: Richard L. Applegate

Publisher:

Published: 1969

Total Pages: 36

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Life histories of Daphnia galeata mendotae, D. retrocurva, D. parvula, D. ambigua, and D. schoedleri are compared with year class strength and food of threadfin shad in Bull Shoals Reservoir from 1965 to 1967. Maximum population density of daphnids was in April, May, and June. Populations declined to insignificant densities throughout the rest of the year. Declines coincided with the inclusion of Daphnia in the diets of threadfin shad smaller than 14 mm. Declines in the summer of 1967 coincided with both young shad predation and high Leptodora kindtii density. Population changes associated with declining year class strength of threadfin shad were an increase of the large D. schoedleri and Leptodora kindtii from nondetectable or trace densities to relatively large populations, and increase from nondetectable densities of daphnids in the summer to detectable densities, and a twofold to threefold increase in the summer standing crops of Bosmina longirostris.

Bibliography on the Blood Chemistry of Fishes
Bibliography on the Blood Chemistry of Fishes

Author: Joseph B. Hunn

Publisher:

Published: 1967

Total Pages: 40

ISBN-13:

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A literature search, starting from scratch, is expensive in terms of time spend in comparison with information gathered. This bibliography includes earlier references by Hunn (1959, 1960) that provide some information to anyone seeking a range of "normal" blood values for fish blood chemistry as well as additional literature that attempts to evaluate the physiological responses of fish to changes in their environment.