Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Wildlife and Fisheries Science


The species composition, abundance, seasonal cycles, distribution, and entrainment mortality of zooplankton and ichthyoplankton were studied in the Big Stone Power Plant cooling reservoir, South Dakota, from January 1979 to April 1980. Mean annual density and biomass of zooplankton for 1979 were 15.8 organisms/liter and 384.7 ug/liter respectively. Cyclopoid copepodites made up 43.0% of the mean annual number, Daphnia pulex, 15.8% and Chydorus sphearicus, 15.2%. Zooplankton density attained a spring maximum of 203.1/liter on 16 May and a fall maximum of 18.7/liter on 15 November. The species composition and density of zooplankton in water entrained by the power plant were similar to those in the reservoir. NO differences were found between dial periods of entrainment. An estimated 48,817.4 kg or 27.1% of the annual number of zooplankton entrained suffered immediate mortality from the effects of entrainment. Five species of ichthyoplankton were collected in the reservoir. The mean density was .053/m³ with a maximum density of .161/m³ in June. The intake area contained significantly higher numbers of ichthoplankton than the other areas of the reservoir. Spawning times and larval fish growth rates were similar to those in other northern lakes. The number of ichthyoplankton in entrainment water is similar to that estimated in reservoir. Lepomis spp. made up 90.5% of the total number entrained. An estimated 100% of all entrained larval fish died from the effects of entrainment.

Library of Congress Subject Headings

Freshwater zooplankton
Fishes -- Larvae
Cooling ponds
Steam power plants -- South Dakota


Includes bibliographical references (pages 62-67)



Number of Pages



South Dakota State University


No Copyright - Non-Commercial Use Only