Discards in large-scale set net in Tateyama Bay

Abstract

In order to identify the discards in set net fishery, monthly field surveys were conducted in a large-scale set net in Tateyama Bay, Chiba prefecture in 2005 and 2006. Discards and landings were recorded in weight by species. A total of 35117.7 kg including 174 species were caught in 24 field surveys. Among these, 32158.9 kg including 82 species were landed and 2958.8 kg including 144 species were discarded. CPUE (catch per haul) and DPUE (discards per haul) were 1463.2 kg and 123.3 kg, respectively. The discard rate (DPUE/CPUE) was calculated to be 0.084. The dominant 10 species of discards were anchovy Engraulis japonica, tripodfish Triacanthus biaculeatus, Pacific pomfret Brama japonica, dolphinfish Coryphaena hippurus, cardinalfish Apogon semilineatus, striped catfish Plotosus lineatus, rabbitfish Siganus fuscescens, pitted stingray Dasyatis matsubarai, threeline grunt Parapristipoma trilineatum and stripey Microcanthus strigatus. There was a significant correlation between catch and discards (r = 0.84, p < 0.05).