We spent a few days in the fishing village of Fulton, Texas.
For those not familiar with the working end of a shrimp boat, the round hoop with black net is TED or turtle excluder device.

Turtle excluder devices promote sea turtle conservation by addressing interactions between sea turtles and trawl fishing gear.
These devices are made of metal bars and mesh that fit inside the neck of a trawl net. While shrimp pass between the bars to the back of the net,
turtles and other larger animals bump against the metal grid and escape through a flap in the mesh.
https://www.fisheries.noaa.gov/southeast/bycatch/turtle-excluder-devices