Effects of temperature on survival, deformations rate and selected parameters of newly hatched larvae of three rheophilic cyprinids (genus Leuciscus).

Experiments were conducted to determine full range of tolerated and optimal water condition for eggs incubation of three species from genus Leuciscus i.e: dace Leuciscus leuciscus (L.), ide Leuciscus idus (L.), and chub Leuciscus cephalus (L.). Spawners were caught from rivers of the northern (Pasleka River drainage) and central (Pilica River drainage) parts of Poland. Fertilized eggs were incubated under controlled conditions at ten different constant temperatures ranging from 4.5 to 29.0 o C. The optimal temperature ranges for the incubation of dace, ide and chub eggs were 7.5 to 12.3oC; 15.7oC and 19.0 to 23.0oC, respectively (considering hatching percentage, incidence of abnormalities and size of hatched larvae), which are close to the water temperature during spawning season. This study also reveals that embryos of studied species can adapt to increasing water temperature due to global warming up to 23.0 o C (dace and ide) and 27.5 o C (chub). Besides, some inter-population differences in the response to temperature were observed.