Effects of different incubation temperatures on the yolk‐feeding stage of Eupallasella percnurus(Pallas)

Embryos and yolk-feeding larvae of lake minnow Eupallusella percnurus were reared at 13, 16, 19, 22 and 25° C with no access to external food. Time from egg activation to first embryonic movements, hatching, filling of swimbladder and final yolk resorption increased with decreasing temperature. At 13° C, c. 40% of larvae were unable to fill their swimbladder. The predicted lower temperature at which development and growth ceased (biological zero, to) was the same for both processes, c. 7·5-10·5° C. There was no ontogenetic shift in the t 0 value. Temperature coefficients for development (Q 10dev .) ranged from 2 to 3 at 19-25° C, but were higher in hatched larvae at lower temperatures. Eggs of E. percnurus had a combination of small size, high hydration and low caloric value of fresh matter. Dry mass of larval tissue on yolk, percentage of dry matter in wet matter, and specific growth rate were maximized at 22 and 25° C. At 19-25° C, energy and matter contained in the initial eggs were converted to body tissue most efficiently. Temperatures from 22 to 25° C are considered optimal for E. percnurus embryos and yolk-feeding larvae and are recommended for their indoor rearing.