Density-dependent process in biological properties of walleye pollock related with biomass fluctuation in the East Sea during the late 20th century

Title
Density-dependent process in biological properties of walleye pollock related with biomass fluctuation in the East Sea during the late 20th century
Author(s)
방민경; 장찬주; 강수경; 김수암
KIOST Author(s)
Bang, Minkyoung(방민경)Jang, Chan Joo(장찬주)
Publication Year
2017-05-30
Abstract
Walleye pollock was one of the most dominant fisheries species in Korean waters during the 1970s-1980s. However, the stock biomass has considerably decreased resulting in the pollock stock collapse after 2008. Although it was expected that the biological characteristics of pollock would be adjusted in accordance with the biomass fluctuation, the systematic investigation of pollock resources in South Korean waters has been difficult because the major spawning ground located in North Korean waters. The National Institute of Fisheries Science has collected information of pollock in the East Sea since the mid-1960s. Using these data, we tried to investigate biological characteristics of pollock during high (1976-1985) and low (1991-2000) biomass periods. Density-dependent growth of pollock was evident in Korean waters: dominance of larger size classes, larger condition factor, and larger length of maturation in the low biomass period. Concurrently, a monthly variation of GSI (gonado-somatic index) indicated that there was a density-dependent process in reproductive property of pollock stock in Korean waters. On the other hand, the pollock population abundance seems to be affected by ocean surface warming after the late 1980s. Our findings suggest that the biomass fluctuation associated with the environmental change in early life stage was thought to be responsible for the changes in the biological properties of pollock.the biological characteristics of pollock would be adjusted in accordance with the biomass fluctuation, the systematic investigation of pollock resources in South Korean waters has been difficult because the major spawning ground located in North Korean waters. The National Institute of Fisheries Science has collected information of pollock in the East Sea since the mid-1960s. Using these data, we tried to investigate biological characteristics of pollock during high (1976-1985) and low (1991-2000) biomass periods. Density-dependent growth of pollock was evident in Korean waters: dominance of larger size classes, larger condition factor, and larger length of maturation in the low biomass period. Concurrently, a monthly variation of GSI (gonado-somatic index) indicated that there was a density-dependent process in reproductive property of pollock stock in Korean waters. On the other hand, the pollock population abundance seems to be affected by ocean surface warming after the late 1980s. Our findings suggest that the biomass fluctuation associated with the environmental change in early life stage was thought to be responsible for the changes in the biological properties of pollock.
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/23948
Bibliographic Citation
3rd PICES/ICES Early Career Scientist Conference, pp.114, 2017
Publisher
PICES/ICES
Type
Conference
Language
English
Publisher
PICES/ICES
Related Researcher
Research Interests

upper ocean dynamics,regional climate modeling,ocean climate change,해양상층역학,지역기후모델링,해양기후변화

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