Maturation process and reproductive biology of fem

Authors: Takahiro Takashima Nozomi Okada Hiroki Asami Noboru Hoshino Osamu Shida Kazushi Miyashita

Publish Date: 2015/12/14

Volume: 82, Issue: 2, Pages: 225-240

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Abstract

The sexual maturation process and reproductive biology of female Arabesque greenling Pleurogrammus azonus in the Sea of Japan off the west coast of Hokkaido was examined using histological observations of ovaries Maturation of P azonus was classified into seven phases based on the presence of nine oocyte stages post ovulatory follicles and residual unspawned ova Although vitellogenesis of P azonus begins annually in August hydrated oocytes were present in September and likely occurred several times during the spawning season until November However few oocytes at the intermediate stages of development were found during the premature and spawning phases Based on these observations the maturation pattern of female P azonus can be classified as “groupsynchronous spawning several batches in a single spawning season” as in other hexagrammid fish The probability of maturation of female P azonus depended on body size rather than age The estimated length at 50  maturity was approximately 240 mm in standard length SL The mean SL of age1 females just before the spawning season varied yearly around the 50  maturity length Overall these findings suggest that the growth of female P azonus before the spawning season at age 1 year can markedly affect spawning biomassWe thank Y Takagi and Y Sakurai at the Faculty of Fisheries Sciences of Hokkaido University T Nagao of the Suttsucho Fisherman’s Cooperative the staff of the Otaru Offshore Fisherman’s Cooperative the captain officers and crew of the RV OyashioMaru and K Itaya M Mitsuhashi K Maeda and other scientists at the Hokkaido Fisheries Research Institute for their cooperation and valuable advice In addition we express thanks to an editor and anonymous reviewers for their helpful and constructive comments on the manuscript This study was supported in part by the Fisheries Agency of Japan under the project “Assessment of Fisheries Stocks in the Waters around Japan”

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