Evaluation of Catch Performance and Environmental Impact of Technical Gear Modifications for a More Sustainable Scallop Dredging Fishery

This study assessed the catch and environmental outcomes of modified scallop dredge designs aimed at reducing environmental impact without changing catch efficiency. Four gear designs were tested: N-Viro dredge with conventional belly bag, N-Viro dredge with skid belly bag, Newhaven dredge with skid belly bag, and the standard Newhaven dredge with conventional belly bag (control). Results showed that the N-Viro dredge alone did not increase catches of market-sized king scallops (Pecten maximus); however, pairing it with a skid belly bag improved catches by 14%–19%. The N-Viro dredge reduced undersized scallop catch by 42% and stones by 67%, with further reductions when combined with a skid belly bag. The N-Viro dredge also decreased fuel consumption by about 30%, while the skid belly bag reduced gear footprint by about 55%. Biomass of bycatch was higher for stonier habitats irrespective of the dredge used, however, skid belly bags caught more bycatch than standard belly bags, and this difference was more pronounced when an N-Viro dredge was also used.