I agree with you that it is a tough proposition for the fishermen to even think of safely handling the snakes for release. I am not sure if there can be a way of ensuring that the snakes don't get caught. Fishermen were even reluctant to use TEDs for a much more benign species like turtle. Ofcourse that fishing technique is different and in deeper seas. Apart from the snakes, other species that are not in demand are just thrown away and not released into the water. I think more interaction with the fishermen and observing their techniques may help us in finding an answer.