Asian Fisheries Society

Reproductive Biology of the Ayu Plecoglossus altivelis (Temminck and Schlegel 1846) from its Southernmost Distribution Range


The ayu Plecoglossus altivelis (Temminck and Schlegel 1846), an annual and amphidromous fish, is generally distributed in the islands of Japan and along the Asian continental coast. Recently, it has been found in two rivers of northern Vietnam and the Tien Yen River is the southernmost distribution range of this species. Morphology of the ayu in Vietnam has been examined; however, its reproductive biology is poorly known. Therefore, this study attempted to describe the fecundity and the egg size of the ayu from this river. Gonadosomatic index (GSI) of the female ayu (160.0–194.7 mm standard length, SL) was 19.7–25.9 %. The number of eggs ranged from 33,548 to 45,114. Egg size ranged from 0.1 to 1.5 mm, with an average diameter of 0.8–0.9 mm. The GSI of the male ayu (153.3–194.7 mm SL) was 2.5–8.3 %. The present findings indicate that the ayu in its southernmost distribution region could spawn at least twice a year, and the breeding period occurs between November and February. This study provides reproductive data on the ayu species, thus contributing to the conservation of endangered ayu populations in Vietnam.

Publication Date : 2017-12-31

Volume : 30

Issue : 4

Page : 274-283

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Date 2017/12/31
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