Migration of Whitespotted Conger (Conger myriaster) Leptocephali to the Harima Nada Sea, Eastern Seto Inland Sea, Japan

• Published in: Aquaculture Science Vol. 60; no. 1; pp. 73 - 80
• Main Authors: Gorie, Shigeaki, Nagasawa, Kazuya
• Format: Journal Article
• Language: English
• Published: Japanese Society for Aquaculture Science 20.03.2012
• Subjects: Conger myriaster; Harima Nada Sea; Leptocephalus; Migration
• ISSN: 0371-4217; 2185-0194
• DOI: 10.11233/aquaculturesci.60.73

This paper describes the occurrence, migration period and vertical distribution of whitespotted conger (Conger myriaster) leptocephali in the northeastern Harima Nada Sea, part of the eastern Seto Inland Sea, Japan as fundamental information for fishery stock management of the species. In 2003 to 2009, a small midwater beam trawl net with a 2.4 mm mesh aperture of a codend was towed with a small boat (9.1 mt) in the three (surface, middle and bottom) layers of the study area (20-25 m in depth) from January to May. The leptocephali migrated to the sea from February to May (mainly from March to April) when sea surface temperature measured 8-18°C. They occurred in the bottom and middle layers (mainly in the bottom layer) in the daytime, but they spread to the surface layer at night. A half of them migrating to the sea were at the metamorphosing stage, which implies that many of the leptocephali move to the northeastern Harima Nada Sea with metamorphosing.