Shark Identification for Cooperative Shark Tagging Program (C-P)
The Cooperative Shark Tagging Program is a collaborative effort between recreational anglers, the commercial fishing industry, and NOAA Fisheries to study the life history of Atlantic sharks. Sharks C-P
Overview
Accurate species identification is critical. To help with identifications we have provided information on size, distinguishing characteristics, distribution, and habitat for sharks in our region.
Common Thresher Shark
Alopias vulpinus
Size
To about 18 ft (5.5 m).
Distinguishing Characteristics:
- Caudal fin sickle-shaped, upper lobe extremely long (about 50 percent of total body length)
- Color brown through shades of gray to nearly black with dark purplish metallic hues above
- Abdomen white, with white extending above pectoral fins
Distribution
Newfoundland, Canada, to Cuba, including the Gulf of America (formerly Gulf of Mexico). Common in the U.S. Northeast.
Habitat
Coastal and offshore from surface to 1,000 ft (305 m); juveniles farther inshore.
Similar Species
Bigeye thresher has large eyes directed upward, deep grooves on top of head, white abdominal coloring that does not extend above pectoral fins.
Apex Predator Publications and Reports – Common thresher shark
Management of Common thresher shark
Dusky Shark
Carcharhinus obscurus
Size
To about 12 ft (3.7 m).
Distinguishing Characteristics:
- First dorsal fin sloping, originating over or slightly before free tips of pectoral fins
- Second dorsal fin with free tip length rarely more than twice fin height
- Color gray or bluish-gray above, white below
- Interdorsal ridge
Distribution
Cape Cod and Georges Bank to Florida, including Gulf of America and Caribbean Sea.
Habitat
Continental waters inshore to the outer continental shelf and adjacent oceanic waters.
Similar Species
Sandbar shark, and bignose shark have higher first dorsal fins originating farther forward. Sandbar shark, most difficult to distinguish, attains smaller maximum size. Bignose shark has longer snout. Silky shark has a second dorsal fin with free tip length usually more than twice fin height. Night shark has green eyes. Bull shark and spinner shark lack interdorsal ridges.
Apex Predator Publications and Reports – Dusky shark
Finetooth Shark
Carcharhinus isodon
Size
To about 6 ft (1.8 m).
Distinguishing Characteristics:
- Snout pointed, shorter than width of mouth; gill slits long
- Find unmarked, pectoral fin undersides pure white
- First dorsal fin originating behind insertion of pectoral fins along inner margin
- Color bluish-gray above, white below
- Teeth slender, erect, smooth or irregularly serrated; similar in both jaws
- No interdorsal ridge
Distribution
New York to Florida, including Gulf of America and Cuba. Rare north of North Carolina.
Habitat
Coastal; inshore shallow waters <20 ft (6 m).
Similar Species
Atlantic sharpnose shark has white spots on back and sides, second dorsal fin originating over or behind middle of anal fins. Blacktip shark and spinner shark have black-tipped fins. Blacknose shark has dusky blotch on tip of snout, yellow-green color.
Apex Predator Publications and Reports – Finetooth shark
Great Hammerhead
Sphyrna mokarran
Size
To about 18.5 ft (5.6 m).
Distinguishing Characteristics:
- Head nearly straight and hammer-shaped, marked by prominent indentation at midline
- First dorsal fin tall and strongly curved
- Color dark olive green to brownish-gray above, shading to white below
- No interdorsal ridge
Distribution
Massachusetts to Brazil, including the Gulf of America and Caribbean Sea. Common off Carolinas in summer. Rare north of North Carolina.
Habitat
Coastal and offshore; near surface to >250 ft (76 m).
Similar Species
Bonnethead has a shovel-shaped head; grows to about 5 ft (1.5 m). Smooth hammerhead and scalloped hammerhead have swept-back "hammers," smaller first dorsal fins, pelvic fins with straight rear margins. Smooth hammerhead lacks central indentation in "hammer."
Apex Predator Publications and Reports – Great hammerhead shark
Lemon Shark
Negaprion brevirostris
Size
To about 10.5 ft (3.2 m).
Distinguishing Characteristics:
- First and second dorsal fins triangular, about equal in size
- Color yellowish-green, brown, or olive-gray above; yellowish below
- Snout blunt, shorter than width of mouth
- No interdorsal ridge
Distribution
New Jersey to Brazil, including the Gulf of America and Caribbean Sea. Uncommon north of Cape Hatteras.
Habitat
Primarily coastal; common around coral keys, docks, bays, and estuaries; young frequent mangroves and grass flats.
Similar Species
Sand tiger has flattened snout, narrow, needle like teeth with 1-2 small cusplets, first dorsal fin set farther back behind pectoral fins. Nurse shark has nasal barbels; lacks distinct lower lobe of caudal fin.
Apex Predator Publications and Reports – Lemon shark
Longfin Mako
Isurus paucus
Size
To about 14 ft (4.3 m).
Distinguishing Characteristics:
- Pectoral fins long (as long as or longer than head), broad-tipped
- Color dark blue to bluish-black above, bluish-gray or white below
- Eyes large
- Mouth area and underside of conical snout dusky or bluish-black
- Caudal fin lunate with single keel on caudal peduncle
- Teeth long, bladelike, smooth-edged, protruding from mouth
Distribution
Georges Bank to Gulf of America. Generally rare throughout its range.
Habitat
Offshore; deep dwelling.
Similar Species
Shortfin mako has smaller eyes, white area around mouth and underside of snout except in large individuals (800-1,000 lb (363-454 kg)), pectoral fins shorter than head length. Blue shark lacks lunate caudal fin, caudal keels, sharply pointed snout. White shark has triangular teeth with serrated edges, blunter snout. Porbeagle has shorter pectoral fins, small secondary keels on caudal fin, teeth with lateral cusplets.
Apex Predator Publications and Reports – Longfin mako shark
Night Shark
Carcharhinus signatus
Size
To about 9 ft (2.7 m).
Distinguishing Characteristics:
- Eyes large and green
- Snout long and pointed
- First dorsal fin small, originating over or behind free tips of pectoral fins
- Teeth smooth-edged or finely serrated; upper teeth with increasingly oblique cusps, pronounced notch on outer margins with 2-5 coarse serration
- Color grayish-blue above, sometimes with small black spots; grayish-white below
- Interdorsal ridge
Distribution
Delaware to Florida, including the Straits of Florida, Cuba, and Gulf of America.
Habitat
Offshore on or along outer continental and insular shelves; in waters 164-328 ft (50-100 m) or deeper (to 1,968 ft (600 m)).
Similar Species
Silky shark and dusky shark lack green eyes. Silky shark has more rounded, swept-back first dorsal fin. Spinner shark lacks interdorsal ridge.
Apex Predator Publications and Reports – Night shark
Nurse Shark
Ginglymostoma cirratum
Size
To about 9 ft (2.7 m).
Distinguishing Characteristics:
- Mouth near tip of snout with conspicuous nasal barbels on each side; deep grooves connecting nostrils with mouth
- First and second dorsal and anal fins broadly rounded; second dorsal fin nearly as large as first dorsal fin
- First dorsal fin originating well behind pectoral fins and over or behind origin of pelvic fins
- Caudal fin with no distinct lower lobe
- Color dark brown to yellow-brown above; lighter below, occasionally with yellowish hue on underside; juveniles often with black spots
- Very small eyes
- No interdorsal ridge
Distribution
Rhode Island to Brazil, including Gulf of America and Caribbean Sea. Rare north of Cape Hatteras.
Habitat
Coastal; bottom dwelling; often in or close to coral reefs; young in very shallow water; adults in progressively deeper water.
Similar Species
Sand tiger and lemon shark have caudal fins with distinct lower lobe; lack nasal barbels.
Apex Predator Publications and Reports – Nurse shark
Oceanic Whitetip Shark
Carcharhinus longimanus
Dorsal view of an oceanic whitetip shark.
Size
To about 11.5 ft (3.5 m).
Distinguishing Characteristics:
- First dorsal fin broadly rounded
- Pectoral fins long, broad, and paddle-shaped
- First dorsal, pectoral, and caudal fins usually with white mottling on tips; small juveniles may have black blotched or black tips on fins and black saddle marks on dorsal surface between fins
- Caudal fin with no distinct lower lobe
- Color brown to olive-gray above, gray-white to yellow below
Distribution
Maine to Argentina, including Gulf of America and Caribbean Sea. Uncommon in U.S. Atlantic EEZ.
Habitat
Offshore in waters >600 ft (183 m); occasionally coastal near oceanic islands. Usually in water temperatures >72°F (22°C).
Similar Species
Broadly rounded, white-tipped first dorsal fin of oceanic whitetip shark distinguishes this species from other Atlantic sharks.
Apex Predator Publications and Reports - Oceanic whitetip shark
Management of Oceanic whitetip shark
Porbeagle
Lamna nasus
Lateral view of a porbeagle shark.
Size
To about 12 ft (3.7 m).
Distinguishing Characteristics:
- First dorsal fin with white patch at trailing edge
- Caudal fin lunate; two keels - one prominent, one secondary
- Snout conical
![Tail region of the porbeagle shark showing the crescent shape and both the main and secondary keel.]()
Teeth smooth, bladelike with lateral cusplets
- Color dark bluish-gray to brown above, white below
Distribution
Newfoundland, Canada, to Massachusetts; seasonally to New Jersey. Common in the U.S. Northeast.
Habitat
Continental shelf waters from surface to bottom to 1,200 ft (366 m) and <66°F (19°C); juveniles farther inshore.
Similar Species
White shark, shortfin mako and longfin mako lack any secondary keels on caudal fins, lateral couplets on teeth. White shark has triangular teeth with serrated edges, blunter snout.
