Effect of variable and constant thermal conditions on embryonic and early larval development of fish from the genus Leuciscus (Cyprinidae, Teleostei)

摘要: The aim of this study was to determine the effects variable and constant thermal conditions on embryonic development three endangered fish species from genus Leuciscus. Wild living spawners dace Leuciscus leuciscus (L.), ide L. idus (L.) chub cephalus were obtained rivers belong - ing Pasleka River basin (northeastern Poland) next transported a hatchery for purpose conducting artificial reproduction. eggs fertilized incubated under variety protocols: slow gradual heating water (M1), rapid increase in temperature at end incuba tion (M2), fluctuating (M3) two temperatures (optimum sublethal). Variable changes also continued after hatching, up yolk sac resorption by larvae. During it shown that relative incubation optimal (12.3°C dace, 15.7°C 19.0°C chub), modifications had no clear influence decrease survival rates (differences among regimes did not exceed 5%) developmental deformations below 1.0%) observed hatched embryos. duration egg rate increased with increasing . In systems modified (from fertilisation commencement exogenous food intake) took 9.5 22.5 days, 6.1 12 days 5.0 10.5 days. stage particular occurred 11.7 23 7.5 13.2 5.5 12.8 chub. Different time hatch reflected level ontogeny Among largest sizes, similar those characteristic optimum temperatures, individuals originating variants where fluctuated. disproportions embryos studied different leaving shells definitely larger than during following stages. This confirmed can adapt due global warming 19.0 (dace), 23.0°C (ide) 27.5°C (chub). results are very important only practical purposes but physiological ecological aspects.