I have a (fishermen) friend on Nantucket who has formed a group called the Seal Abatement coalition and they are approaching it from a legal angle. According to them there is language in the federal law which does allow for reduction of the population in areas where it is causing danger to humans. I don't know if you have been to Great Point recently but seals have taken over the place and will chase humans. Seals have killed what surf fishing was there.
I think it is just a matter of a few years (<5) befor a human is killed from a GW shark.