Interactions between artisanal and industrial tuna fisheries: insights from a decade of tagging experiments

The suite of species taken by artisanal fishers targeting tuna often includes species caught in the larger industrial tuna fisheries, leading to concerns that industrial fisheries may reduce local fish availability and consequently impact upon artisanal catch rates. This study provides supporting evidence that industrial purse-seine fisheries may impact upon artisanal and subsistence fishers. A tagged population of skipjack and yellowfin tuna of known size was monitored through time and the probability of recapture was used as a measure of interaction with the industrial purse-seine fisheries. The probability of recapture was positively associated with areas where relative purse-seine fishing effort was higher. The results indicate that skipjack and yellowfin tuna may have longer residency times in nearshore habitats than in open ocean habitats. Lower recapture probabilities in areas currently closed to purse-seine fishing provided empirical evidence that area closures for industrial fisheries may assist with the management of artisanal fisheries. Finally the results suggest that the proximity to industrial purse-seine fishing may also be an important component for decision makers when planning and evaluating the performance of artisanal fisheries in the western Pacific region.