2. See What You've Got: "When you pull up behind the shrimp boat, drop a lot of chum initially to see what's there," Trosset says. "If there are more tunas than bonitos, slow your rate of chumming as you drift farther from the shrimp boat. This will calm the bonitos down, causing them to meander instead of feeding in a frenzy, letting you target the blackfin." Of course, if you see only bonitos come up in your initial heavy dose of chum, save the trash and move on to another boat. Don't invest your trash in bonitos.