Market Organization, Producer Prices, and Fossil-Fuel Consumption in an Offshore Fishery: Evidence from Vietnamese Skipjack Tuna Gillnet Vessels

This study examines how first-sale market organization, realized producer returns, and harvesting-related fuel consumption are jointly associated in Vietnam’s offshore skipjack tuna gillnet fishery. Using 242 vessel observations from repeated cross-sectional surveys in 2008, 2012, 2018, and 2024, this study first compares channel-specific prices within the same vessel-year, avoiding the mechanical relationship between marketing shares and quantity-weighted average prices. Direct sales to processors are associated with an average observed price differential of about 12.4% relative to sales through middlemen among mixed-channel vessels. Realized annual producer price is not detectably associated with fishing days, trip frequency, or days spent at fishing grounds per trip after conditioning on vessel capacity and survey-year effects. Total annual fuel use is strongly associated with fishing days, engine power, and gear capacity; its association with realized price is positive but imprecise and specification-sensitive. An exact accounting decomposition suggests that, in the pooled estimates, the price–fuel association is more evident in catch scale than in fuel use per tonne, although the component coefficients are not statistically distinguishable and the price–catch relationship varies across survey waves. The findings connect fisheries value-chain governance with bioeconomic incentives and aggregate fossil-fuel consumption, while emphasizing that the repeated cross-sections do not identify causal behavioural responses.