Barndoor Skate

The barndoor skate is a flat-bodied fish with a large, disk-like body with sharply angled corners and a pointed snout. Its pectoral fins have evolved into broad, flat, wing-like appendages used to propel the fish through the water. These fins have a concave front edge with rounded posterior corners. Like sharks, it has a boneless skeleton made of cartilage, a tough, elastic substance composed of collagenous and/or elastic fibers, cells, and a firm, gel-like substance called the matrix. It has slot-like body openings called gill slits on the underside of the body beneath the pectoral fins that lead from the gills. The dorsal fins are close together and far removed from the tail. It has two eyes on its dorsal surface, located about 5.5 centimeters (2.2 in) apart. The fish's upper surface is brown to reddish brown with many scattered darker spots, lighter streaks, and reticulations. The center of each pectoral fin is marked with an oval spot or blotch. The lower surface is light, white to grey, blotched irregularly with gray spots. The barndoor skate is unique from other species of skate in its having a straight line that begins at the snout and ends at the anterior margin of the outer corner of the disk, but stopping short of the disk. The barndoor skate is one of the largest skates found in the North Atlantic Ocean. …

The barndoor skate occurs in a range extending from the banks of Newfoundland, the southern Gulf of St. Lawrence, and along the northeastern coast and offshore banks of Nova Scotia south to North Carolina. Reports in the 19th century said the range of the fish extended as far south as northeastern Florida, but more recent research suggests that the Florida discoveries may have actually been a misidentification of R. floridana. It is found on various types of ocean bottoms, including soft muddy, sandy, and rocky bottoms. It can be found from the shoreline to depths to 750 m (2,460 ft), although it is most commonly found at depths less than 150 m (500 ft). It inhabits waters in a broad range of temperatures, from just above freezing to 20 °C (68 °F). It appears to move closer to shore in the autumn and further out to sea in the warmer months. It tolerates brackish water where the salinity is as low as 21 to 24 parts per thousand, but it prefers salinity between 31 and 35 parts per thousand. It is believed to not exhibit any north-south migratory patterns.

The fish is carnivorous, with its prey consisting mainly of benthic invertebrates and fishes. Such food items include polychaetes, gastropods, bivalve mollusks, rock crabs, cancer crabs, spider crabs, lobsters, shrimps, squids, and fishes including spiny dogfish, alewife, Atlantic herring, menhaden, hakes, sculpins, cunner, tautog, sand lance, butterfish, and various flounders. Juveniles primarily subsist on benthic invertebrates such as polychaetes, copepods, amphipods, isopods, crangon shrimp, and euphausiids. Individuals have been found with the denticles on the snout worn smooth, indicating that the snout is used to dig in the mud or sand to obtain bivalve mollusks.