Mortal condition of sand lance Ammodytes personatus in Ise Bay [Japan] during estivation
2000
"Yamada, H. (Mie-ken. Fisheries Technical Center, Hamashima (Japan)) | Kuno, M. "
"Mortal condition of Japanese sand lance Ammodytes personatus in Ise Bay during estivation was studied under laboratory condition. Effects of nutritional condition before estivation on the mortality of sand lance during estivation were investigated by experiment 1 . Almost all sand lance could survive when the condition factor was higher than 3.2 before estivation. In the natural estivation grounds, sand lance with smaller condition factor than 3.2 at the beginning of estivation was below 1.9% of the total number of individuals in each year. It suggests that the mortality during estivation due to malnutrition would be very low. In experiment 2 , effects of water temperature on the mortality during estivation were investigated. Sand lance with low condition factors (3.3 in mean) at the beginning of estivation were kept under various temperature during estivation. Then most sand lance could survive in conditions below 25degC. In the natural estivation grounds, the water temperature during estivation has never been over 25degC in the past. It suggests that the mortality during estivation due to high temperature would be very low. Thus there is little effect of external environment on the mortality of sand lance during estivation."
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