Using hydrodynamics to modify fishing performance of a demersal fishing gear

This study demonstrates how hydrodynamics can be used to influence the fishing performance of towed demersal fishing gears. Sea trials are performed in the sea star fishery to show how modifications to the gear design alter the hydrodynamics of the turbulent wake and consequently affect the catching performance of trawl gears. The trials are performed on cockle and mussel beds and the effect of the gap between the towing beam and the seabed, and the effect of the size of the beam are investigated. Two different beam sizes are utilized where a large beam reduces the mussel bycatch and increases the sea star catch rate if positioned a suitable distance over the seabed. The catch rate is independent of the distance between the beam and the fishing line within the investigated interval.