Environmental Implications of Discarding Fish in Northern Spanish Coastal Bottom Otter Trawl Fisheries

Abstract Overfishing contributes to the depletion of fish stocks. Among fishing practices, discarding fish is a waste of valuable resources and results in lost income that is associated with its effects on future stock growth. This practice depends on several factors, although trawl fisheries account for the highest quantity of discards. In this work, the effects of a specific section of the Galician (Northwestern Spain) bottom trawl fishery were evaluated by using the ecological footprint, focusing on the contribution of the rate of discards. We selected fishing grounds and carbon footprints as the categories for the analysis. The results showed that 11.6 global hectares (gha) per metric ton of catch were required for an average fishing trip, ranging between 2.2 and 27.1 gha per metric ton. Discards represented 55% of this value, while the carbon footprint only represented 11%. Therefore, measures are needed to reduce the significant effects of discards, especially in these fisheries. The findings indicate that the discard ban promoted by the Common Fisheries Policy could reduce the ecological footprint of these fisheries by 3.4 gha per metric ton of catch landed on average.