How technical change has boosted Fish Aggregation Device productivity in the Indian Ocean tuna fishery

Abstract

Excess harvesting power can threaten the long-term sustainability of fisheries. Indicators of excess harvesting power include input-output-based estimates of economic production efficiency. The increasing use of Fish Aggregating Devices (FADs) has boosted fishing productivity in high-seas tuna fisheries, perhaps beyond the biological capacity of the stocks, and is an object of global debate. We carried out a Data Envelopment Analysis of relative changes in production efficiencies of the French purse-seine fleet targeting tropical tuna in the western Indian Ocean using two fishing strategies, 1) on floating objects (FOB) and 2) free swimming schools (FSC) using tuna catch and effort data spanning 1992–2019. We show that FOB fishing evolved dramatically through time via the introduction of new technology with an estimated change of 4.2%yr− 1 (9.2%yr− 1 2007–2019), in contrast to 1.5%yr− 1 for FSC. While the level of efficiency in the use of inputs has barely changed for FOB fishing, a steady increase for FSC is observed. Factors that influence the productive capacity of vessels include the number of fishing sets, vessel power, fuel, and tuna price. Immediate plans to improve input-based management in this region are needed to prevent further risks of overfishing to yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tunas.