Survival and growth rates of whitefish ( Coregonus lavaretus L.) larvae after experimentally delayed hatching

Abstract

The time of hatching of whitefish ( Coregonus lavaretus) embryos was artificially delayed so that it coincided with suitable thermal and food conditions in stocked lakes. By cooling the hatchery water to 1–2°C, successive batches of whitefish embryos were obtained on 21 and 28 April and 7 May. Then the batches of larvae were reared in tanks for 15 days at a constant temperature of 14.0 ± 0.1°C. Survival of the corresponding batches of fish during the whole rearing period was 89, 88, and 86%, respectively. Mean instantaneous rate of net biomass gain of the successive batches of fish was 11.71, 10.78, and 11.27% day −1. Thus, delaying hatching time did not reduce either survival or growth rate of whitefish larvae.