Record Details

Distribution of kokanee (Oncorhynchus nerka) fingerlings in summer as related to some environmental factors

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Title Distribution of kokanee (Oncorhynchus nerka) fingerlings in summer as related to some environmental factors
Names Fortune, John David (creator)
Chapman, Donald W. (advisor)
Date Issued 1964-05-15 (iso8601)
Note Graduation date: 1964
Abstract Natural populations of kokanee fingerlings were studied in Odell Lake, Oregon from June 1962 to September 1963. Vertical and horizontal distributions were determined in relation to temperature, zooplankton, and light during the summer of 1963. Food habits of the fingerlings were also examined. A mid-water townet was employed for sampling the fish. Vertical series of temperatures and plankton samples were taken in conjunction with each fishing effort. Diaptomus was taken selectively by the kokanee. Daphnia was taken in proportion to relative abundance. Cyclops was taken least in relation to relative abundance. The fingerlings showed a disproportionate horizontal distribution with the greatest density being at the west end of the lake. This distribution appeared to be associated with the principal known spawning area, greater zooplankton numbers, and slightly lower terriperatures. Currents resulting from wind action might have influenced the horizontal distribution. The vertical distribution of kokanee became more restricted as the summer progressed. When surface temperatures rose, the kokanee began to associate with the thermocline at about 60 feet. The mean of the temperatures found at the modes of vertical distribution was 11.1 C. A multiple regression analysis indicates there was a positive correlation with Diaptomus and with time, and a negative correlation with the product of temperature and time. The numbers of kokanee caught at the surface during August and September were positively correlated with moonlight.
Genre Thesis/Dissertation
Topic Fish-culture -- Oregon
Identifier http://hdl.handle.net/1957/21327

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