Hydrodynamic optimization of turtle excluder device for enhanced trawl performance and sustainability

This study attempted to hydrodynamically optimize Turtle Excluder Devices (TEDs) in trawl fishing nets in order to balance bycatch reduction with operational efficiency. Researchers conducted flume test experiments on different TED configurations (bar spacing, installation angle, and flow velocity) in a model shrimp trawl, and used Fast Fourier Transform analysis (FFT) to understand the hydrodynamic force oscillations. The presence of a rigid TED increases mean codend drag by 26.2% to 42.1% compared to an empty codend, with drag amplifying as bar spacing decreases and as installation angle and flow velocity increase. A Genetic Algorithm framework identified the optimal TED configuration as an 88 mm bar spacing, a 60° installation angle, and a 0.6 m/s flow velocity. This optimized configuration achieved substantial improvements, reducing mean drag by 45.25%, suppressing drag oscillation amplitude by 64.87%, and improving relative codend stability by 28.76%.