The boycott is a good place to start. It is the consumer demand for their delicious flesh that puts a high price on the head of every swordfish, or tuna, or striped bass for that matter.
Aquaculture will be the wave of the future. Commercial fishing is a dying industry, the last vestige of hunting and gathering as opposed to agriculture and industry.
IMHO, Since when are American commercial fishermen conservation-minded? If they were, our fisheries would not be in such a sorry state. Their lobbyists seem to fight anything that might prevent them from killing as many fish as possible
as fast as possible. Greed makes people do some incredibly stupid and self-destructive things. It has always been thus. The cod fishermen in Canada have put themselves out of business. US commercial fishermen are on the verge of doing the same.