Relationship between sea-surface temperature and catch fluctuations in the Pacific stock of walleye pollock in Japan

Abstract

This paper investigates the relationship between sea-surface temperature (SST) and catch fluctuations in the Pacific stock of walleye pollock Theragra chalcogramma in Japan. Incorporating time lags between years of birth and harvest, the correlation coefficients between the catch and SST in two regions off the east coast of Hokkaido were calculated. The catch in year t had a high negative correlation with the SST during January-April and November-December of the years t-2 and t-3 in the spawning area. These results coincided well with the correlation observed in the northern 'Sea of Japan' stock. Both analyses suggested that the long-term catch fluctuations of the two stocks could be explained by the same mechanism, that is, the fluctuations would be explained by the SST in their spawning area during the spawning season using 2-3 or 3-5 years time lags, which corresponded to the dominant age of the catch within these two stocks.

Catch forecasting and relationship between water temperature and catch fluctuations in snow crab Chionoecetes opilio in the western Sea of Japan

“…The details of mechanisms that explain why water temperature strongly influences catch fluctuation, and possibly the fluctuation in population abundance, have not yet been elucidated. However, as mentioned before, the same phenomena have been detected in several species and stocks of fish 10–13,17 . Noto and Yasuda 18 discussed the population decline of the Japanese sardine and indicated that the winter–spring sea surface temperature (SST) in the Kuroshio Extension is a controlling factor that determines the year‐class strength.…”

“…However, as mentioned before, the same phenomena have been detected in several species and stocks of fish. [10][11][12][13]17 Noto and Yasuda 18 discussed the population decline of the Japanese sardine and indicated that the winter-spring sea surface temperature (SST) in the Kuroshio Extension is a controlling factor that determines the year-class strength. They also noted that from the egg to the larval stage, positive correlations between water temperature and catch (although the coefficient were not significant, implying that high sea surface temperatures led to high mortality) were observed in the spawning grounds around Kuroshio from January to March when sardines spawned and hatched.…”

“…discussed the fluctuation in sandfish catch by using catch forecasting models incorporating environmental factors. Oh et al 11,12 . investigated the fluctuations in walleye pollock catch using information on water temperatures and migration patterns, and showed that the catch fluctuations in Pacific stock and northern Sea of Japan stock could be explained by the same mechanisms.…”

“…Sakuramoto et al 10 discussed the fluctuation in sandfish catch by using catch forecasting models incorporating environmental factors. Oh et al 11,12 investigated the fluctuations in walleye pollock catch using information on water temperatures and migration patterns, and showed that the catch fluctuations in Pacific stock and northern Sea of Japan stock could be explained by the same mechanisms. Watanabe 13 developed a new mathematical model that showed a stockrecruitment relationship in sandfish using water temperature data and spawning stock biomass, and discussed how to manage the sandfish population through fisheries regulations.…”

A Common Concept of Population Dynamics Applicable to Both Thrips imaginis (Thysanoptera) and the Pacific Stock of the Japanese Sardine(Sardinops melanostictus)

“…This indicates that the population size in month i could be determined in proportion to the population size in month i-1, i.e., the relationship between the populations sizes in month i and that in month i-1 can be expressed using a simple proportional model. The validity of a proportional model is not explicitly noted, however, the fluctuations of the catches in the species such as snow crab [22], sandfish [23,24] and walleye pollock [25] are already explained without assuming a density-dependent effect in the fluctuation mechanism in catches. The (4).…”