Fisheries biological study of yanagimushigarei Tanakius kitaharai - I. Age determination of yanagimushigarei Tanakius kitaharai (pleuronectidae) from otoliths in the Sea of Japan off Kyoto prefecture.

Abstract

The present paper treated the age determination of yanagimushigarei Tanakius kitaharai (Pleuronectidae) from otoliths (sagittae). The otoliths used were collected from the 4067 specimens caught off Kyoto Prefecture by a research beam trawl and a Danish seine from 1981 to 1983 and gill nets in 1986. There appear alternating concentric opaque and hyaline zones in an otolith. Each zone was easily read in most otoliths, but acetate replicas of frontal sections were made for a small number of undecipherable otoliths. An opaque zone was formed from spring to summer and corresponded to the duration of a fast growth. Results from age determination based on the number of opaque zones show that the 1980 year-class is a dominant yearclass. Otoliths are recognized to be useful for the age determination of yanagimushigarei.