Toward sustainable trawling: Evaluating a double-wheeled trawl footgear in the northern shrimp (Pandalus borealis) fishery

This study evaluated a novel experimental bottom trawl equipped with a double-wheeled footgear developed for the inshore northern shrimp ( Pandalus borealis ) fishery in Atlantic Canada. The gear combines two rockhopper disks per unit, aligned with the towing direction, aiming to reduce seabed impact while maintaining catch efficiency. Nineteen paired hauls compared the experimental trawl with a traditional trawl using standard footgear. Generalized linear mixed-effects models (GLMMs) were used to assess differences in catch efficiency, bycatch abundance, and trawl geometry, while size selectivity was evaluated using spline-based catch comparison models. Results showed similar shrimp catch rates and size selectivity between trawls, indicating comparable fishing efficiency. However, the experimental trawl produced significantly higher bycatch of juvenile groundfish, including Greenland halibut ( Reinhardtius hippoglossoides ) and redfish ( Sebastes spp.), and captured substantially more sea pens (Order Pennatulacea), providing compelling evidence of unintended seabed disturbance. Observations of mud accumulation on the gear and catch further support this interpretation, likely caused by horizontal chains connecting the footgear disks, dragging along the seabed and functioning similarly to tickler chains. Although direct seabed impact measurements were not conducted, these findings highlight the need for gear modifications, particularly to the steering chain configuration, to reduce unintended seabed interaction. Future studies using underwater cameras are recommended to better characterize gear-seabed interactions and guide design improvements.