Spiny Dogfish (Squalus acanthias)

The spiny dogfish is the most prominent member of the Squalidae family of dogfish sharks. Some live in relatively shallow water close to shore; others inhabit great depths. They vary widely in length, and one of their chief anatomical characteristics is the lack of an anal fin.

Identification

The body of the spiny dogfish is elongate and slender. The head is pointed. The color is slate gray to brownish on top, sometimes with white spots, and fading to white below. It has spines at the beginning of both dorsal fins; these spines are mildly poisonous and provide a defense for the spiny dogfish.

Sharks

Today there are at least 370 species of sharks worldwide. Like all fish, sharks are vertebrates, but ichthyologists place them in a separate class from most bony fish because the shark’s skeleton is made of cartilage instead of bone. Sharks also have five to seven gill slits on each side of the head, allowing each gill to vent separately into the surrounding water. Bony fish, in contrast, have on each side of their bodies one gill opening that is covered by a bony plate called the operculum.

Sharks also lack the gas-filled swim bladders of most bony fish. Instead, sharks have evolved a different means of maintaining buoyancy: They have extremely large livers that contain oils that are lighter than water. These oils, coupled with the cartilaginous skeleton, make sharks almost neutrally buoyant.

Atlantic Angel Shark (Squatina dumeril)

The Atlantic angel shark is frequently mistaken for a ray because of its flattened, triangular body. This fish is unlike a ray, however, as its gill slits are lateral and create a deep indentation between its head and its pectoral fin.

The Atlantic angel shark is brownish- to bluish-gray on the back and whitish on the belly, and it has a mid-dorsal row of denticles. The large mouth is terminal, and each tooth has a broad base with a long, pointed central cusp. The pectoral fins are not attached to the body at the rear, and Atlantic angels swim without making much use of them.

Basking Shark (Cetorhinus maximus)

The second largest shark in existence today, growing to 45 feet, the basking shark is a member of the mackerel shark family and is basically harmless to humans.

A dark gray or slate-gray fish fading to a paler shade on its belly, the basking shark gets its name from its habit of swimming slowly at the surface. As a plankton feeder, it will not take bait, being too large for sportfishing anyway.

Blacktip Shark (Carcharhinus limbatus)

The blacktip shark reaches just over 8 feet in length; the alltackle world record is a 270-pound, 9-ounce fish taken off Kenya in 1995.

It is dark bluish-gray on the back and whitish below, with a distinctive silver-white stripe on each flank; young fish are generally paler. As the name implies, it is black-tipped on the insides of the pectoral fins, as well as on the dorsal, the anal, and the lower lobe of the caudal fins in young fish. This shading may be faint, especially on the first dorsal fin, and it fades with growth.

Blue Shark (Prionace glauca)

A member of the requiem shark family, the blue shark is very slender and streamlined, with a long and pointed snout that is much longer than the width of its mouth.

Appropriately, it is a deep, brilliant blue or a dark cobalt to indigo blue above, fading gradually to white below. With up to three rows of functional teeth in each jaw, the larger teeth in the upper jaw are “saber shaped,” or broadly convex on one side and concave on the other; the teeth are serrated along the edges, and those in the lower jaw are narrower.

Bonnethead Shark (Sphyrna tiburo)

The bonnethead shark is the smallest member of the hammerhead sharks, the family characterized by having eyes located at the far ends of extended lateral lobes.

The bonnethead is particularly distinctive in appearance because it has a smooth, broadly widened head, frequently described as “spade shaped,” which has more curve to it than do the heads of any other hammerheads. Also, the front of the head is lacking a median groove, which is pres- ent in other hammerheads. Gray to grayish-brown in color, the bonnethead shark seldom exceeds 3 feet in length, maturing at about that length to bear 6 to 12 live young at one time.

Bull Shark (Carcharhinus leucas)

A large member of the requiem shark family, the bull shark is also called the freshwater whaler and the river whaler because it is most common inshore around river mouths and can adapt to life in freshwater.

This is the species that is landlocked in Lake Nicaragua in Nicaragua and has gained fame as a man-eater because it has been repeatedly implicated in attacks on humans. Also known as the Zambezi shark in southern African waters, the bull shark is one of the three most dangerous sharks in that area, along with great white and tiger sharks, due to its relative abundance in inshore habitats where people are more likely to be attacked.

Hammerhead Sharks (Sphyrna species)

Hammerhead sharks occur worldwide; the most prominent species include the great hammerhead (S. mokarran), the smooth hammerhead (S. zygaena), the scalloped hammerhead (S. lewini), and the bonnethead shark (see).

Hammerheads are easy for even a novice to identify, with eyes located at the ends of two thin lobes and the overall structure resembling a hammer. One possible reason why the head takes on a hammer shape may be that the shape is ideal for turning and locating odors, making the best use of the electroreceptors present in all sharks, which in turn makes detecting food an easier chore.

Lemon Shark (Negaprion brevirostris)

A requiem family shark, the lemon shark grows to 11 feet at maximum, although it is usually between 5 and 8 feet long. A potentially dangerous shark, it may rest on the bottom in coastal waters in groups of 4 to 6 and become aggressive when in the vicinity of spearfishing.

It is commonly yellow-brown, although it can also be muddy dark brown or dark gray with olive sides and a paler belly. It has a blunt and broad snout that appears rounded from below. The second dorsal fin is almost equal in size to the large first dorsal fin, and the upper lobe of the tail is much larger than the lower.

Lemon sharks are good inshore, light-tackle sportfish that inhabit western Atlantic waters from New Jersey to Brazil; in the eastern Pacific they extend from southern Baja California, Mexico, and the Gulf of California to Ecuador.

Leopard Shark (Triakis semifasciata)

The leopard shark is a striking fish, so named for its leopardlike black spots, which run in crossbars across its back and sides over a lighter gray background.

It has an elongate body and a short snout that is bluntly rounded. Attaining lengths of up to 7 feet, the leopard shark inhabits inshore sand flats and rocky areas, often in schools with smoothhound sharks. As a smaller, less aggressive species of shark, it is not considered dangerous.

Porbeagle Shark (Lamna nasus)

The porbeagle shark is a member of the mackerel shark family, as are the great white and the mako sharks, and bears a resemblance to both species.

The porbeagle has a robust, cobalt blue body with a perfectly conical snout that ends in a point. It is easily identified by its teeth, which are smooth and have little cusps on each side of the base. It often has a distinctive white area at the base portion of the first dorsal fin; this fin is farther forward than it is on mako or white sharks.

Sandbar Shark (Carcharhinus Plumbeus)

The sandbar shark is an inshore fish and a good light-tackle fighter, growing usually to between 5 and 7 feet long. A relatively heavy-bodied fish, it is dark bluish-gray to brownishgray and has a pale or white belly.

There is a distinct ridge on the back between the first and the second dorsal fins, and the first fin is large and pointed, starting over the middle of the pectoral fin. Its snout is shorter than the width of its mouth, appearing rounded from below.

Sand Tiger Shark (Carcharias taurus)

Previously called Odontaspis taurus, the sand tiger shark is the most common shark sighted along Atlantic beaches.

It grows to about 9 feet and is grayish-brown or tan, with dark brown spots along the sides that grow more numerous toward the tail; although it bears a resemblance to the tiger shark, it has a larger second dorsal fin, a longer snout, and strongly projecting teeth.

Usually caught accidentally by surf casters fishing for other fish, sand tigers are sluggish and offer little resistance when hooked. In the western Atlantic, they occur from the Gulf of Maine to Argentina.

Sharpnose Sharks (Rhizoprionodon species)

There are six sharpnose sharks in the Rhizoprionodon genus of the requiem shark family, all sharing a similar external appearance that is characterized by a long, flattened snout.

The best-known member of the family is the Atlantic sharpnose (R. terraenovae), which is a very popular small species as an inshore food fish and a small gamefish in the Gulf of Mexico. It grows to between 2 and 4 feet in length and has the characteristic long and flattened snout, as well as a slender brown to olive-gray body with a pale belly. The dorsal and the caudal fins may be edged in black, especially in the young, and often there are small, scattered whitish spots on the sides.

Shortfin Mako Shark (Isurus oxyrinchus)

The shortfin mako is by far the most popular of angling sharks, exceeding 1,000 pounds in weight and 13 feet in length.

The shortfin mako has a streamlined, well-proportioned body that is most striking for a vivid blue-gray or cobalt blue coloring on its back, which changes to a lighter blue on the sides and a snowy white on the belly; this brilliant coloring fades after death to a grayish-brown. Other characteristic features are a conical, sharply pointed snout; a large flattened keel on either side of the caudal peduncle; and a lunate (crescent-shaped) tail with lobes of nearly equal size.

Thresher Sharks (Alopias species)

Known by a variety of names, the thresher shark is characterized by its well-muscled tail, the upper lobe of which is usually as long as the rest of the body. These sharks use their tails to herd baitfish into a mass by slapping or thrashing the water, then stunning or injuring fish before swallowing them.

Grayish to dark charcoal in color, the thresher shark turns abruptly white on the belly and may be mottled on the lower half of the body. The thresher is further identified by the absence of a keel on the caudal peduncle; by its small, pointed, and broad-based teeth; and by its comparatively smooth skin.

Tiger Shark (Galeocerdo cuvier)

One of the largest of the requiem sharks, the tiger shark grows to 24 feet. It is infamous as one of the most dangerous sharks.

Although some sharks will attack and kill humans without necessarily eating them, the tiger shark is especially fearsome because it is well-known as a man-eater, often devouring the remains of its victims.

White Shark (Carcharodon carcharias)

Although a relatively uncommon deep-water fish, the white shark occasionally enters shallow waters and will attack, without provocation, humans and small boats alike; because it often lingers near islands and offshore colonies of seals and sea lions, which are some of its preferred foods, it is thought that some attacks on humans occur because the white shark mistakes divers or surfers in wet suits for seals.

It is undoubtedly the most dangerous shark, due to a combination of size, strength, ability, and disposition to attack and because of the many recorded attacks that have taken place in the twentieth century.

Tope (Galeorhinus galeus)

One of the smallest members of the requiem shark family, the tope is an active and highly sought species within its extensive range.

The tope has a slender body; a prominent, long, pointed snout; long pectoral fins; and a large and strong tail fin with a large lower lobe. It is a bottom-roaming inhabitant of inshore environs that commonly weighs from 20 to 40 pounds but may grow as large as 75 pounds and can exceed 5 feet in length. It is reported to live as long as 55 years. Despite its size, it is favorably regarded by anglers for its vigorous fight.