Effects of Feeding and Temperature on Survival and Growth of Larval Black Rockfish Sebastes schlegeli in Rearing Conditions

Abstract

Effects of feeding and temperature on survival and growth of black rockfish larvae were studied in four rearing experiments. In the feeding regime experiment, growth and survival rates were not significantly different between the combined rotifers and Artemia feeding regime and the Artemia only regime. In the feeding level experiment, total length at 20 days after birth was significantly different by feeding level as (1.5) = (1.0) > (0.5) > (0.1), where the feeding level (1.0) is the same level as fed in the hatchery and the other values indicate ratios compared to (1.0) . In the different temperature experiments, survival rates at the intermediate temperatures of 14°C, 18°C and 22°C were significantly higher than those at 10°C and 24°C. Growth rate tended to increase as temperature increased within the examined range from 10°C to 24°C. When larvae were reared under diel temperature change (14-18°C), survival and growth rates were between 14 and 18°C of fixed temperatures showing no beneficial effects of a diel change of temperature. The most efficient rearing method for hatchery rearing was concluded to be: using (1.0) feeding level of Artemia only during the larval period at a temperature range approximately 16-20°C.