Leptocephali of Anguilla japonica Found in the Waters South of the Okinawa Islands

Abstract

Fifty-two specimens of leptocephalus were collected in the waters south of the Okinawa Islands by the R/V Hakuho-maru, Ocean Research Institute, University of Tokyo, during November and December, 1973. These larvae are characterized by an olive leaf shape, a vent at three-fourths of total length (developing larva), straight intestine, 113–119 total myomeres, 6–13 ano-dorsal myomeres, major vertical blood vessels usually lying at segments 16, 38 and 44, large pectoral fin, and no pigment except for the chorioid of the eye. The authors conclude that these larvae are those of Anguilla japonica T. et S., demonstrating that too much confidence should not be placed on the number of ano-dorsal myomeres in identifying anguillid leptocephali to the species level. © 1975, The Japanese Society of Fisheries Science. All rights reserved.