Effects of Temperature on Utilization of Yolk by Chinook Salmon (Oncorhynchus tshawytscha) Eggs and Alevins

Abstract

Growth, development and survival of chinook salmon (Oncorhynchus tshawytscha) during the yolk absorption period (fertilization to complete yolk absorption) were examined at 6, 8, 10, and 12 °C. Higher rearing temperatures reduced both the duration of the yolk absorption period and the overall amount of energy available for tissue growth during that period. Salmon encountered a metabolic energy deficit before yolk reserves were exhausted; tissues were resorbed during absorption of the last 10 mg (dry weight) of yolk. Salmon held above 10 °C experienced reduced survival, hatched and emerged precociously, and were smaller at hatching, at emergence, at maximum tissue weight and at complete yolk absorption than fish at lower temperatures.Key words: temperature, yolk utilization, Oncorhynchus tshawytscha, fish eggs, alevins