Characterization of bigeye tuna habitat in the Southern Waters off Java-Bali using remote sensing data

Bigeye tuna (Thunnus obesus) habitat was investigated based on catch data and environmental satellite data, such as sea surface temperature (SST), sea surface chlorophyll (SSC), and sea surface height deviation (SSHD) data in the Southern Waters off Java and Bali. First, we obtained daily fish catch data and monthly satellite data for SST, SSC, and SSHD for 2006-2010. Then, we analyzed the relationship between daily catch data and satellite data by combining the statistical method of generalized additive model (GAM) and geographic information system (GIS). Seven GAM models were generated with the number of bigeye tuna as a response variable, and SST, SSC, and SSHD as predictor variables. All of the predictors of SST, SSC, and SSHD were highly significant (P < 0.001) to the number of bigeye tuna. Values of SST, SSHD, and SSC in bigeye tuna habitat ranged from 24.8 to 28.7 °C, −3 to 7 cm, and 0.05 to 0.17 mg/m3, respectively. Validation of the predicted number of bigeye tuna with the observed value was significant (P < 0.05, r2 = 0.56). SST was the most important environmental variable to the number of bigeye tuna caught, followed by SSHD and SSC.