Reproductive rates of copepods in experimental ponds in Oregon

Graduation date: 1970Rates of birth, death and population change were calculated for Cyclops sp. and Diaptornus forbesi in Soap Creek Ponds V-VIII near Corvallis, Oregon during the interval April, 1968 to April, 1969. An egg ratio method was used in calculating these rates. Duration of development of the eggs of both species was determined in the laboratory and found to be highly correlated with water temperature. Even though the ponds are adjacently located and morphometrically very similar, significant differences in birth rates and population densities between ponds were noted. Eggs were collected most frequently in pond VI for Cyclops sp. and in ponds VII and VIII for D. forbesi. Consequently, populations of each species were most stable in these respective ponds. Predation by small fishes was probably the main cause of zooplankton mortality in all four ponds