Preliminary capacity utilization analysis of the WCPO purse seine fleet using Data Envelopment Analysis (DEA)

WCPFC has noted concern over the size of WCPO fleets relative to available fishing opportunities. An example process to identify excess-capacity was presented to SC11. In this paper a more sophisticated analysis is performed to identify relationships between vessel fishing capacity and fishing effort for the WCPO purse seine fleet. First, Data Envelopment Analysis (DEA) is applied to identify potential fleet over capacity. This approach compares each vessel against others to evaluate annual output levels (total tuna catch) relative to the potential output if all vessels performed optimally (the ratio being the level of capacity utilisation) for given inputs (fixed input being vessel age, variable inputs being days fished and number of sets). Second, the potential numbers of vessels within optimally performing fleets are estimated based upon recent effort levels and levels consistent with effort limits in the WCPO, and compared to actual fleet sizes. Finally, to identify factors affecting vessel capacity utilisation and suggest appropriate metrics for fishing capacity, estimates are regressed against vessel characteristics and external factors (e.g. fuel prices).