1988/89 체제변환에 따른 동해 명태의 생태학적 특징과 어업생산량의 변화

Abstract

Walleye pollock (Gadus chalcogrammus, hereafter pollock) was one of the most dominant species in Korean waters, but its stock has rapidly decreased since the late 1980s and was collapsed completely in the early 21st century. In this study, we investigated how the changes in characteristics of pollock was related to the 1988/89 regime shifts in Korean waters using atmospheric data from KMA (Korean Meteorological Administration), oceanographic data from KODC (Korea Oceanographic Data Center), and biological data including length, weight, and gonad weight of pollock which were collected by National Institute of Fisheries Science for three decades from 1973 to 2003. During the high biomass period (1973-1985), the size and condition factor for pollock were smaller, while during the low biomass period (1991-2003), they were larger. Between the two period, the catch production of pollock in Korean waters were considerably (92%) decreased (95,320 to 7,377 Metric Ton), indicating a regime shift around late 1980. This regime shift is also shown in zooplankton biomass and chlorophyll-a concentration. The regime shift seems to be related with an increase in frequency of the sea surface temperature higher than 12℃ which is unfavorable for pollock larval survival. The sea surface temperature shift appears to be linked with Arctic Oscillation. Our results suggest that climate changes, inaddition to overfishing, could contribute towe investigated how the changes in characteristics of pollock was related to the 1988/89 regime shifts in Korean waters using atmospheric data from KMA (Korean Meteorological Administration), oceanographic data from KODC (Korea Oceanographic Data Center), and biological data including length, weight, and gonad weight of pollock which were collected by National Institute of Fisheries Science for three decades from 1973 to 2003. During the high biomass period (1973-1985), the size and condition factor for pollock were smaller, while during the low biomass period (1991-2003), they were larger. Between the two period, the catch production of pollock in Korean waters were considerably (92%) decreased (95,320 to 7,377 Metric Ton), indicating a regime shift around late 1980. This regime shift is also shown in zooplankton biomass and chlorophyll-a concentration. The regime shift seems to be related with an increase in frequency of the sea surface temperature higher than 12℃ which is unfavorable for pollock larval survival. The sea surface temperature shift appears to be linked with Arctic Oscillation. Our results suggest that climate changes, inaddition to overfishing, could contribute to