Influence of aquaculture on fishing strategies: Insights from Galician small-scale fisheries

Abstract

Marine ecosystems have been traditionally exploited by coastal communities in several ways, especially by fishing. More recently, aquaculture has emerged as an activity through which coastal communities have diversified their economies. Thus, many regions of the world face the challenge of allowing both activities to maximise their yields while complying with conservation objectives. Our study area represents a paradigm of this reality as intensive mussel aquaculture has expanded in the region since the 1950's, forcing small-scale fisheries to adapt to the new scenario. Using a cross-disciplinary approach, we identified two métiers in the studied fleet: a) one composed mostly of queen scallop catches (Queen Scallop Métier - QSM), and b) a more heterogeneous one with a varied composition of Crustacea, Cephalopoda and Fishes (Mixed Composition Métier - MCM). The MCM is strongly spatio-temporally correlated with mussel raft locations, which indicates how the bottom trawl small-scale fleet has adapted its strategies to the presence of aquaculture. Moreover, the rich community associated with mussel rafts is reflected in the heterogeneous catch composition (of valuable species) of the fishing operations carried out near mussel rafts. However, accumulated biodeposits have attracted detritus feeding non-commercial species, creating a new ecological paradigm and posing operational difficulties for the fleet and higher discards.