A Trial of Evaluation of Activity in Yellowtail, Seriola quinqueradiata Larvae
1993 Volume 41 Issue 3 Pages 339-344
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1993 Volume 41 Issue 3 Pages 339-344
Starvation tests were conducted during 1987 to 1991 mainly at 20 °C in order to evaluate the activity of yellowtail larvae. Tolerance to starvation was expressed as survival activity index (SAI) .
The larvae showing higher SAI values in the starvation test also showed higher survival rates in the rearing test from 0 to 10 days after hatching. The larvae floating on the surface of the hatching tank when water turbulence was stopped, showed higher SAI than non-floating larvae. The larvae obtained from younger adult fish (33) showed higher SAI than those from the older fish (5+, 6+) in the starvation test. There was a correlation between the SAI and hatching rate. These results suggest that the SAI value is considered to reflect the activity of yellowtail larvae, and can be used as a practical indicator of the larval activity in the seed production. Based on the results of experiments on temperature effect, the following equation between SAI (y) and water temperature (x) was introduced within a range of temperatures from 18 to 24°C : y = -1.13 x + 38.75 (r = -0.9935) .
