When I went I was under the impression that a lot of charters don't let you keep all of the meat anyway. I think they usually keep a lot of it to sell to the local markets and restaurants (at least this was the case in Kona). We caught some yellowfin, but nothing huge, so they let us keep all of it. They will probably let you keep all the meat you want, and then take care of the rest themselves. That may be something you would wan't to talk to the captain about before heading out. We had a great time though, I would love to do it again- best of luck to you.
Now I see someone else had the same experience. I was there last summer so I am sure that is still generally the case.