Morphology and distribution of juveniles of three cynoglossid fishes occurring in Osaka Bay from August to October

Abstract

Morphology and distribution of juveniles of cynoglossid fishes were investigated in Osaka Bay during August–October in 2012–2014. Three cynoglossid (Cynoglossus robustus, C. joyneri and C. interruptus) juveniles were collected by a sledge net. C. robustus were distinguished from the other two species by the number of dorsal and anal fin rays. C. joyneri and C. interruptus have similar numbers of dorsal and anal fin rays, but could be distinguished by the relative position of the left eye and the mouth, the pigmentation pattern of the ocular side, and left eye diameter. From the minimum observed standard length at metamorphosis in each species, (C. robustus 9.6 mmSL, C. joyneri 7.2 mmSL, C. interruptus 11.0 mmSL) it was inferred that C. joyneri completed metamorphosis at a smaller size (<10 mmSL) than the other two species. Patterns of distribution of the three cynoglossid juveniles differed: C. robustus mainly at 20–30 m depth in the middle of Osaka Bay in August and September, C. joyneri mainly at 10–20 m depth in the northern part of Osaka Bay in October, C. interruptus widely distributed at 10–30 m depth in Osaka Bay mainly in October.