Page 327 - (DK) Ocean - The Definitive Visual Guide

SHARKS, RAYS, AND CHIMAERAS 325

ORDER HEXANCHIFORMES With its elongated, eel-like body occasionally comes to the surface. It ORDER HEXANCHIFORMES
and flattened head, the frilled shark feeds on deep-water fish and squid.
Frilled Shark bears little resemblance to other The male has two long claspers on Bluntnose Sixgill
sharks. The most noticeable difference the belly, which are used to transfer
Chlamydoselachus anguineus is that its mouth is at the front of its sperm to the female when mating. Shark
LENGTH Up to 6 / 2 ft head instead of on the underside. In This species has yolk sac viviparity,
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(2 m) addition, while most modern sharks meaning that the eggs hatch inside the Hexanchus griseus
WEIGHT Not recorded have five pairs of gill slits, the frilled mother, which then gives birth to live LENGTH Up to 18 ft
(5.5 m)
shark has six, each with a frilled edge. young. Up to 12 young are born as
DEPTH Mostly
66–4,921 ft Its small teeth are also unusual, each long as two years after fertilization. WEIGHT Up to at least
(20–1,500 m) having three sharp points. Trawlers fishing for other deep- 1,300 lb (600 kg)
DISTRIBUTION Worldwide but discontinuous Frilled sharks have been observed sea species often catch frilled sharks DEPTH Up to 8,202 ft
(2,500 m)
swimming with their mouths open, as by-catch. Because this species
displaying their conspicuous white reproduces so infrequently, it is DISTRIBUTION Tropical and temperate waters
teeth, leading to the suspicion that the especially vulnerable, and is listed worldwide
teeth act as a lure for prey. This shark as Near Threatened on the IUCN
lives near the seabed in deep water but Red List of endangered species. This enormous deep-water shark is
sometimes spotted by divers in shallow
water at night, but its more usual haunt
is rocky seamounts and mid-ocean
ridges. Its thick-set, powerful body has
one dorsal fin, a large mouth lined
with comb-like teeth, and six gill slits.
Its fins are soft and flexible, not rigid
like those of most sharks. Fish, rays,
squid, and bottom-living invertebrates
are this shark’s typical prey, although
larger adults sometimes also hunt for
seals and cetaceans.

ORDER HEXANCHIFORMES species that have seven gill slits—more on the tip of the single dorsal fin and and aggressive on the rare occasions
than any other living shark species. on the upper part of the tail. Females when it is captured. It is occasionally
Sharpnose Sevengill It lives in deep water and hunts squid, have yolk sac viviparity and give caught up as by-catch in trawl nets,
Shark crustaceans, and fish near the seabed. birth to 6–20 young at one time. The and this may be contributing to a
sharpnose sevengill shark is rarely seen
Like the sixgill sharks (see above), it
reduction in its numbers. It is listed
has comblike teeth. Young fish have alive and little is known of its feeding as Near Threatened on the IUCN
Heptranchias perlo
black markings, which fade with age, and breeding behavior, but it is lively Red List of endangered species.
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LENGTH Up to 4 / 2 ft
(1.4 m)
WEIGHT Not recorded
DEPTH Up to 3,300 ft
(1,000 m), typically
90–2,360 ft (27–720 m)
DISTRIBUTION Tropical and temperate waters
worldwide, except northeastern Pacific
The sharpnose sevengill shark, as its
name suggests, has a sharply pointed
snout and is one of only two shark

size. Also known as the spurdog or
ORDER SQUALIFORMES
spiny dogfish, this sleek, dark gray
Piked Dogfish shark has two dorsal fins, each with
a sharp spine in front of it. Irregular
white spots decorate its sides, especially
Squalus acanthias
LENGTH Up to 5 ft (1.5 m) in young fish, and it has a pointed snout
and large oval eyes. It was once very
WEIGHT Up to 20 lb (9 kg)
common and was possibly the most
DEPTH Up to 4,800 ft abundant species of shark, but it is
(1,460 m), typically
0–2,000 ft (0–600 m) now threatened globally as a result of
overfishing. These sharks do not begin
DISTRIBUTION Worldwide, except tropics, North to breed until they are 20 years old
Pacific, and polar waters and may live to be 30 or so years old.
They grow very slowly, and the young OCEAN LIFE
Sharks are not normally shoaling fish, take up to two years to develop inside
but piked dogfish aggregate into huge the mother. Some populations migrate
groups numbering thousands of thousands of miles seasonally in order
individuals, often all of one sex and to avoid very cold water.