As ocean temperatures rise in midsummer, dolphin—a.k.a. mahi mahi—can be found as far north as Massachusetts. Most are hooked on the troll. Problem is, unless you’re dealing with a giant bull, typical trolling outfits meant for tuna or marlin easily overpower the average dolphin. Fortunately, these fish love to congregate below anything floating—be it a piece of wood or a high flyer marking a lobster pot or fish trap. Find a pot field, and you (or your charter captain) can ditch the trolling spread and fill the box with inshore spinning gear light enough to make a 10-pound mahi battle memorable. Here’s the plan.