Impact of mechanized clam dredging on the discarded megabenthic fauna on the Catalan coast (NW Mediterranean)

Abstract There is an important small-scale fishery using mechanized dredges and targeting clams (mainly wedge clam Donax trunculus striped venus Chamelea gallina ) along the Catalan coast (NW Mediterranean Sea). This study evaluated for first time discards impact of dredging on coast. To this end, three surveys were performed board standard vessels (September November 2016 January 2017). Surveys conducted in main fishing areas (Rosas Bay, South Barcelona Ebro Delta). The composition caused to discarded species was assessed a three-level scale (undamaged; minor or partial damage; lethal damage). Our revealed that large proportion catch (between 67–82% weight) discarded. Even though about 63% undamaged, 11% showed damage 26% damage. Infaunal epifaunal with soft-body fragile shells most impacted by activity (e.g. sea urchin Echinocardium mediterraneum (~89%) bivalve Ensis (~74%)). results different levels target area.