Fishery biology of ribbon fish Trichiurus japonicus Kagoshima - Japan

Ribbon fish population is one of the important fishery resources in Kagoshima Bay, southern Japan. Age and growth and the annual total mortality coefficient were examined. The age marks on otolith formed once a year between December and February. Females grew faster reached a larger size at age than males. Developmental stages of oocytes and maturity stages of the ovaries were determined after examination of histological section, and batch fecundity was obtained from the frequency of egg diameter. Ribbon fish in Kagoshima Bay mature at age one and the spawning season lasts long from April to October. Main fishing gears of ribbon fish are longline and bottom trolling.Landing volume and number of fishermen landing were examined. Multiple correlation analysis indicated that monthly landing volumes were affected by CPUE and especially the number of fishermen. Ribbon fishes of Kagoshima Bay are relatively moderate in growth among the Japanese populations, having a multiple spawning with annual fluctuation in the spawning period and peak, their catches are consists of relatively large and mature individuals and the stock seems to be considerable exploited.