동해 명태 자원량 변동에 따른 생물학적 특징 변화

Abstract

To investigate environmental effects on the pollock stock we compared differences in biological and ecological parameters during high (1970s-1980s) and low (1990s-2000s) biomass periods. Pollock length frequencies showed that a larger sizeclass was dominant in the low biomass period when their condition factor was larger, as well. This indicates that growth was relatively better during the low biomass period. The gonad-somatic index also revealed that the peak spawning season was in February during the high biomass period but changed to December during the low biomass period. Population Stock Density (PSD), which is index of size structure based on length frequency, was higher during the low biomass period than during the high biomass period, indicating recruitment intensity of pollock became weaker in 1990s.lass was dominant in the low biomass period when their condition factor was larger, as well. This indicates that growth was relatively better during the low biomass period. The gonad-somatic index also revealed that the peak spawning season was in February during the high biomass period but changed to December during the low biomass period. Population Stock Density (PSD), which is index of size structure based on length frequency, was higher during the low biomass period than during the high biomass period, indicating recruitment intensity of pollock became weaker in 1990s.