AN ILLUSTRATED FIELD GUIDE TO THE FISHES OF GRAY'S REEF NATIONAL MARINE SANCTUARY

Group l - SHARKS AND RAYS

Sharks are not particularly abundant at Gray's Reef and, fortunately for divers, the most commonly observed shark at Gray's Reef, the nurse shark, is not considered dangerous to man. At least 19 of the 350 species of sharks worldwide are known to occur on Georgia's shelf waters (see systematic checklist). Based upon longline and trawl samples from sandy bottoms in the Georgia Bight (Low and Ulrich 1984), the sandbar shark appears to be most abundant followed by the tiger, smooth dogfish, Atlantic sharpnose, spiny dogfish, scalloped hammerhead, lemon, dusky, sand tiger, and silky shark. For more information on the identification of sharks and other non-bony (cartilaginous) vertebrates (sawfishes, guitarfishes, electric rays, skates, stingrays, butterfly rays, eagle rays, and manta rays) see Castro (1983), Dahlberg (1975), Garrick (1982), Hoese and Moore (1977), Moore and Farmer (1981), Robins et al. (1986), and Schwartz (1984). Note that the lengths given are average and not maximum reported sizes.

Family Orectolobidae (carpet sharks)

NURSE SHARK Ginglymostoma cirratum

Nasal barbels, grooves connecting nostrils to mouth, teeth minute, eyes small, no lower lobe of caudal fin, dorsal fins of nearly equal size, color brownish to yellowish gray with small black spots. This sluggish bottom feeder crushes shellfish with its pavement-like teeth. It is commonly seen lying practically motionless on the bottom near or under ledges at Gray's Reef. Rhode Island to Brazil. 8 ft.

Family Odontaspididae (sand tigers)

SAND TIGER Odontaspis (=Eugomphodus) taurus

Gill slits anterior to origin of pectoral fins; second dorsal fin nearly as large as the first; teeth long, narrow, smooth and protrude from the mouth. The single developing fetus feeds on eggs within the maternal uterus. Individuals have been observed and photographed following divers who were carrying speared fish at Gray's Reef in January. Maine to Brazil. 4-9 ft.

Family Carcharhinidae (requiem sharks)

SILKY SHARK Carcharhinus falciformis

Skin silky, leading edge of first dorsal fin curved, second dorsal fin and anal fin with long posterior tip, serrated triangular teeth more strongly serrated at base becoming more oblique toward the corners of the mouth. Tropical and subtropical seas worldwide, Massachusetts to Brazil in the western Atlantic. 7-8 ft.


BULL SHARK Carcharhinus leucas

Snout very short and broad, dorsal fin high and triangular, pectoral fins as long as distance from pectoral fin origin to tip of snout, upper teeth triangular and heavily serrated, lower teeth narrower and finely serrated. Tropical coastal waters and freshwater rivers worldwide, New York to Florida and Gulf of Mexico in the western Atlantic. 7-8 ft.


DUSKY SHARK Carcharhinus obscurus

Snout short, raised ridge on back between dorsal fins, origin of first dorsal fin posterior to origin of pelvic fins. Similar to silky shark but first dorsal fin clearly triangular. Tropical seas worldwide except oceanic Pacific; Massachusetts to Brazil in the western Atlantic. 8 ft.


SANDBARSHARK Carchathinus plumbeus

Stocky body, first dorsal fin large and originating over ail of pectoral fin, low ridge on back between dorsal fins, widely spaced dermal denticles (scales) without teeth on free edges. Warm seas worldwide, Massachusetts to Brazil in the western Atlantic. 7 ft.


TIGER SHARK Galeocerdo cuvieri

Snout blunt, long labial furrows around corners of mouth, small spiracle behind eye, caudal fin with long upper lobe, slight keel on caudal peduncle, curved short teeth with finely serrated edges and deep outer notch, spots on young, bars on adults. Warm seas worldwide, Cape Cod to Uruguay in the western Atlantic.


LEMON SHARK Negaprion brevirostris

Snout very short, second dorsal fin nearly as large as the first; Grst dorsal fin begins behind pectoral fin; teeth narrow, triangular, smooth-edged; underside yellowish. New Jersey to Brazil. 8-10 ft.


ATLANTIC SHARPNOSE SHARK Rhizoprioltodon terraenovae

Long labial furrows at corners of mouth; snout long and pointed; origin of second dorsal fin behind origin of anal fin; scattered white spots on adults; teeth triangular, oblique, strongly notched, finely serrated only in older individuals. Bay of Fundy to Yucatan. 3 ft.

Family Sphyrnidae (hammerhead sharks)

SCALLOPED HAMMERHEAD Splhlryna lewini

Head wide and flat; central indentation on anterior margin of head; ventral tips of pectoral fins gray-black; teeth triangular, smooth-edged. The indentation on the anterior margin of the head is less pronounced in the great hammerhead (S. mokarran) and absent in the smooth hammerhead (S. zygaena). The bonnethead (S. tiburo) has a narrower, shovel-shaped head. All occur in Georgia shelf waters. New Jersev to Brazil and the Pacific.

Family Squalidae

SPINY DOGFISH Squalus acanhtias

Robust spines in front of both the first and smaller second dorsal fin, color slate gray or brownish usually with small white spots scattered over the body. Occassionally adundant near reefs in the winter. Labrador to Cuba. 3-4 ft.

Family Dasyatidae (stingrays)

SOUTHERN STINGRAY Dasyatis americana

Body flattened into a diamond-shaped but broadly rounded disc; tail narrow, whip-like with a low ridge and one or two sharp serrated spines on the upper surface and a broad ridge on the lower surface. The spine, called the sting, carries a potent toxin secreted by glands in the skin which can produce a painful wound or reaction. The roughtail stingray (D. centroura) also occurs on the Georgia coast and is distinguished by spiny thorns on the tail and lack of upper ridge on the tail. Stingrays often dig into sediments in search of food leaving crater-like depressions. New Jersey to Brazil. 4-5 ft.

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