Abstract
To identify climate-related habitat changes and variations in abundance and distribution of Ommastrephes bartramii in the northwest Pacific Ocean, an habitat suitability index (HSI) model was developed in this study including sea surface temperature (SST), photosynthetically active radiation (PAR), and sea surface height anomaly (SSHA). The catch-per-unit-effort (CPUE) of O. bartramii gradually decreased between 2006 and 2015, and the latitudinal gravity centres (LATG) of the fishing effort shifted southward. Correlation analyses suggested that CPUE was positively related to SST, PAR, and the areas of suitable and optimal habitat, but negatively correlated with SSHA and the percentages of poor habitat. A significantly positive correlation was found between the LATG and the average latitude of the most preferred SST, PAR, and the average latitude of the area with an HSI between 0.9 and 1.0. From 2006 to 2015, the annual declined CPUE was highly consistent with the increase in areas of poor habitat and the reduction in areas of suitable and optimal habitats. The south-approaching LATG coincided with the southward migration pattern of the latitude of the HSI area in the range of 0.9–1.0. Moreover, compared to the El Niño events, the La Niña events, and normal climate condition yielded enlarged suitable habitat areas for O. bartramii, and the LATG moved further north.
Spatial spectra of sea surface temperature and chlorophyll “a” concentration fields in the marginal seas of the northwest Pacific Ocean
