NIPPON SUISAN GAKKAISHI
Online ISSN : 1349-998X
Print ISSN : 0021-5392
ISSN-L : 0021-5392
Originals
Changes in the specific gravity of eggs, larvae, and juveniles of Hippoglosoides dubius, and the relationship between egg development and water temperature
KOTA SUZUKIMITSUHIRO NAKAYAHAE-KYUN YOOTAIHEI MATSUDATETSUYA TAKATSU
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2017 Volume 83 Issue 4 Pages 580-588

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Abstract

 To assess transportation in the early life history stages in the flathead flounder Hippoglosoides dubius, we measured the specific gravities of the eggs at 9℃ and the larvae and juveniles at 9℃ and 12℃ using density-gradient and density-bottle methods. We also examined the effect of temperature (1, 3, 6, 9, and 12℃) on the duration between fertilization and yolk sac absorption. Eggs in glass beakers had lower specific gravities than the water densities experienced in one of the spawning grounds, Funka Bay. In contrast, the specific gravities were higher than the water densities in Funka Bay in yolk sac larvae, almost the same in early preflexion larvae, and increased with advancing development from the late preflexion larval to juvenile stages. The duration from fertilization to yolk sac period decreased with increasing water temperature. Thus, annual variation in the water temperature in the field combined with transport directions and speeds at various depths may affect the transportation of flounder eggs and larvae.

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© 2017 by The Japanese Society of Fisheries Science
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