This study explores the optimal spatial strategy for fishing efforts for subdivided on fishing grounds for different economic performance. We analyze the Japanese off-shore longline fishing vessel groups targeting swordfish and blue shark in the North Pacific. The seasonal dynamic optimal spatial strategy to maximize the economic performance is explored with identified fishing grounds by the cluster analysis. This study carries out the sensitivity analysis to see how the optimal strategy changes when the input parameters (e.g., ex-vessel price), objective functions and benefit allocation scheme between vessel owners and crews are varied. The results suggest that the robust optimal spatial strategy is to minimize the days per trip to maintain flexibility of destination of fishing grounds.