Fluke are flatfish, a species of Atlantic flounder, also called “summer flounder.” They can weigh in at a pound or so or be heaved aboard in seven to ten-pound sizes. For some reason, fluke were scarce for a few years but that has changed. Fluke fillets may be cooked like sole or flounder. The flesh is moist and sweet. From the larger fish, crosswise slices or steaks, much like halibut, lend themselves to various broilings, bakings and sauteings.