Acoustic deterrent devices and modified fishing gear designs reduce harbor porpoise bycatch, preventing drowning deaths and associated population welfare impacts.
Bycatch drowning represents a significant welfare harm occurring at industrial scale for harbor porpoises. These air-breathing mammals, when entangled in gillnets, experience the progressive physiological distress of drowning — struggling against entanglement, oxygen depletion, and ultimately death — a profoundly aversive process. Pingers offer a proven, cost-effective solution but face adoption barriers from equipment costs and battery maintenance burdens on fishers. Regulatory mandates with fisheries support programs have shown success in Norway and Denmark, providing models for broader implementation.