Forecasting fishing ground of calamary in the northern South China Sea according to habitat suitability index

Based on the data of bottom trawl fishery within shelf area at depth of less than 200 m by a fishery information network from 2009 to 2014, and environmental data obtained from remote sensing, we established the habitat suitability index (HSI) models for calamary (Uroteuthis sp.) in the northern South China Sea. The sea surface temperature, sea surface height and concentration of chlorophyll-a were determined by nonlinear regression modeling. The integrated HSI models for each month, which were established using least square method for assigning weight coefficients to the environmental factors, could explain the relationship between distribution of fishing grounds and environmental factors effectively, and deduce the most suitable range and variation tendency of the environmental factors. High catches per unite effect (CPUE) values of the trawl fishery were mainly in the areas where the HSIs were higher than 0.5, and the other high HSI areas might be potential fishing grounds. Weight coefficients for the environmental factors in the integrated HSI models suggest that chlorophyll-a concentration is the most important factor influencing the distribution of fishing grounds. Verification of the HSI models shows an accuracy of over 75%. The study indicates that the integrated HSI models based on different weight coefficients for environmental factors can better predict fishing grounds of calamary in the northern South China Sea.