Spatio-Temporal Distribution of Sardinops sagax in the North Pacific: Optimal Environmental Characteristics

Sea surface temperature (SST) and chlorophyll concentration in the North Pacific in 2019–2020 were analyzed based on the data of light net fertilization fisheries, including chlorophyll-a, sea surface height (SSH), and data regarding other environmental factors. The spatial and temporal distribution characteristics of catch per unit effort (CPUE) and its relationship with key environmental factors of Sardinops sagax fishery in the Far East were analyzed by spatial superposition map and frequency analysis, empirical cumulative distribution function, K-S test, and GAM model. The results showed that the geographical fishery center ranges from 147°–153°E and 39°–43°N and moves to the northeast from April to August, returning to the southwest from September to November. According to the frequency analysis and empirical cumulative distribution function, the optimal SST and chlorophyll concentration in the central fishing area were10.0–18.0 ℃ and 0.2–0.6 mg/m3, while the optimal sea level was 0.2–0.7 m. The K-S test showed that high CPUE was closely related to SST, chlorophyll concentration, and sea surface height, and the optimal ranges were 10.9–18.9 ℃, 0.2–0.6 mg/m3, and 0.2–0.7 m, respectively. The GAM model simulation results showed that the optimal SST of high CPUE was 11.0–17.0 ℃, the optimal chlorophyll concentration was 0.3–0.8 mg/m3, and the optimal sea surface height was 0.1–0.4 m. Overall, the results showed that the optimal SST, chlorophyll concentration, and sea surface height were 11.0–18.0 ℃, 0.2–0.6 mg/m3, and 0.2–0.7 m, respectively.