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

ISBN-13:

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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

ISBN-13:

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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.

Mortality Studies on Cutthroat Trout in Yellowstone Lake [by] Orville P. Ball and Oliver B. Cope
Mortality Studies on Cutthroat Trout in Yellowstone Lake [by] Orville P. Ball and Oliver B. Cope

Author: Orville P. Ball

Publisher:

Published: 1961

Total Pages: 72

ISBN-13:

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In a study of the Yellowstone Lake cutthroat trout, Salmo clarki lewisi, by the U.S. Fish and Wildlife Service, effects of environment on mortality of eggs, immature fish, spawners, and postspawners were measured for various components of the population in Yellowstone Lake (Wyoming). Five methods for estimating mortality of adults on spawning runs are described, with counting and tagging as the principal procedures. Of the total number of eggs deposited in the gravel, 60 to 75 percent died before hatching, and 99.6 percent had died by the time the fingerlings enetered Yellowstone Lake. In Arnica Creek runs, 48.6 percent died in the stream, 40.2 died later in the lake of natural causes, 7.6 were taken by fishermen, and 3.6 percent were alive 2 years later. The white pelican is a serious predator on cutthroat trout in Yellowstone Lake. From 1949 to 1953 fishermen caught 11.6 percent of the catchable trout available to them. Migrations of adult fish in Yellowstone Lake were traced through tagging.