FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

This study applied the generalized additive models (GAMs) to examine the relationship between sailfish catch per unit effort (CPUE) from 1998 to 2004 and environmental variables, which included satellite-derived remote sensing data and other spatio-temporal variables in the marginal seas of the northwestern Pacific Ocean. The results of the stepwise GAMs analysis found less important influences upon sailfish CPUE from chlorophyll-a concentration (Chl-a) and sea surface height anomaly (SSHA). The final GAMs fitting model was constructed by the spatio-temporal variables, including the year, month, latitude, longitude, sea surface temperature (SST), Pacific decadal oscillation (PDO), southern oscillation index (SOI), and the bathymetry of operational factors. There was a significant relationship (R2 = 0.52, P < 0.0000) among the predicted values of GAMs analysis and nominal sailfish CPUE. It showed that the relatively high sailfish CPUE was found in June and July and a higher sailfish CPUE between 28 °C and 30 °C SST. The highest value of sailfish CPUE was found in 29 °C SST. These results can benefit to examine progressively the feeding and spawning habitats and its possible migratory route of sailfish in the northwestern Pacific Ocean.