SREL Reprint #0387




Effects of Thermal Effluent on Populations of Mosquito Fish

M. Catherine Ferens and Thomas M. Murphy, Jr.



Reproduction, sex ratios, and size structure were examined in populations of the mosquito fish Gambusia affinis from lentic and lotic environments with different thermal conditions.  Winter temperatures at the time of sampling ranged from 16.5C in a pond receiving no thermal effluent to 44C in a heated pond.  Sex ratios varied greatly among locations with no apparent relation to temperature or habitat.  No females from nonheated areas were carrying eyed embryos.  The percentage of females 30 mm or more in length bearing eyed embryos increased linearly with water temperature.  Size structure was also altered as indicated by the curvilinear decrease in the ratio of median to maximum length with increasing water temperature.  Secondary productivity was higher in heated environments.


SREL Reprint #0387

Ferens, M.C. and T.M. Murphy Jr. 1974. Effects of thermal effluents on populations of mosquito fish. p. 237-245. In Thermal Ecology, edited by J.W. Gibbons and R.R. Sharitz. CONF 730505. Atomic Energy Commission.

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