Estimation of coastal drift net selectivity and its application for sophisticated research and management of pelagic fish

2015 Fiscal Year Final Research Report

• Project/Area Number: 25450271
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: TOKAI Tadashi 東京海洋大学, その他部局等, 教授 (30237044)
• Co-Investigator(Kenkyū-buntansha): HU Fuxiang 東京海洋大学, 学術研究院, 教授 (80293091) ; SHIODE Daisuke 東京海洋大学, 学術研究院, 助教 (40361810)
• Co-Investigator(Renkei-kenkyūsha): KAWABATA Atsushi 水産総合研究センター, 中央水産研究所, 室長 (60371811) ; FUJIMORI Yasuzumi 北海道大学, 水産科学研究科(研究院), 教授 (40261341)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 水産学 / 調査用流し網 / 網目選択性 / マサバ / マイワシ / 適正目合 / 羅網機構 / 資源調査

Outline of Final Research Achievements

A drift net series consisting of several net panels of different mesh sizes was used to investigate pelagic fish resources in the waters around Japan. First, mesh selectivity of research driftnet for Japanese sardine was estimated. The relationship of body girth against the mesh perimeter suggested that Japanese sardine was efficiently caught by the capture process of “wedged” or “gilled”. Next, selection curves of research driftnet for chub mackerel were estimated in the two periods of June-July and September-November. Fish caught in June-July had slightly greater fork length than those in September-November, and they also had a lower condition factor implying a smaller body girth following spawning. The pooled relative catching intensity steeply declined for fish with fork length over 300 mm at the current mesh combination, and the addition of two panels with larger mesh sizes (82 and 106 mm) kept a constant intensity for fish below 350 mm fork length.

Free Research Field

水産学