"Unlike other forms of marine debris, fishing gear is specifically designed to catch marine life. Under certain conditions, derelict gear can continue to catch and kill organisms for years."
The issue is economic incentives do not align. The fisher can bring it back to shore and probably have to pay to dispose of it in a landfill. Or they can drop it in the ocean for free, while creating a negative externality.
If someone setup a fund to pay fisherman 5 cents a pound to bring their nets back, and then they would deal with disposal, they could avert most of this. No one has stepped up with $50 million a year tho to solve this.
"Unlike other forms of marine debris, fishing gear is specifically designed to catch marine life. Under certain conditions, derelict gear can continue to catch and kill organisms for years."