Class

CHAPTER

CHIMAERAS, SHARKS, SKATES AND RAYS

Chondrichthyes

Class: Chondrichthyes Number of families: 57 families

PHYSICAL CHARACTERISTICS

Chimaeras (kye-MIHR-uhs), sharks, and skates and rays are the class of fishes whose skeleton is made of cartilage (KAR-teh-lej), a tough but flexible supporting tissue. Chimaeras have large heads and long bodies that taper to a whiplike tail. The skin is smooth and rubbery and has no scales. Sharks and skates and rays have gills that open to the outside, have no swim bladder, and have a sandpaper-like skin covering rather than scales. Sharks range in size from tiny to huge. Skates and rays are flat from top to bottom and have massive pectoral (PECK-ter-uhl) fins and long, sometimes whiplike tails.

GEOGRAPHIC RANGE

Chimaeras, sharks, and skates and rays live all over the world except in the Antarctic region.

HABITAT

Chimaeras usually live on muddy bottoms near the shore. Sharks live in coastal waters on the bottom or out at sea in open water or at the bottom. Skates and rays live on the bottom in saltwater or freshwater or move back and forth between the two.

DIET

Chimaeras eat bottom-dwelling animals such as crabs, clams, and fishes. Some sharks are fierce predators (PREH-duh-terz) that hunt and eat every sort of sea animal. Others simply strain plankton, the microscopic (MY-kro-SKA-pihk), invisible to the phylum class subclass order monotypic order suborder family

Big Fish, Tiny Diet

The whale shark is the largest fish in the world at a length of 59 feet (18 meters) and eats the smallest food, plankton.

Man-eater?

More people have been killed by domestic livestock, such as pigs, than by sharks.

eye, plants and animals that drift in bodies of water. Most skates and rays eat bottom-dwelling shelled animals and bony fishes.

BEHAVIOR AND REPRODUCTION

All chimaeras, sharks, and skates and rays reproduce by internal fertilization (FUR-teh-lih-zay-shun), meaning egg and sperm unite inside the female. Some species lay fertilized (FUR-teh-lyezd) eggs, and the young develop outside the mother. In other species the young develop inside the mother, hatch within the mother, and are born freely swimming. Chimaeras, sharks, and skates and rays engage in parental care before laying eggs or giving birth to pups.

CHIMAERAS, SHARKS, SKATES, RAYS, AND PEOPLE

A few species of chimaeras are fished commercially for food. Sharks are used for their meat, oil, and hides, which are used for leather. Skates and rays are eaten in some areas, and the skin sometimes is used for leather.

CONSERVATION STATUS

The World Conservation Union (IUCN) lists eight species of sharks and skates and rays as Critically Endangered, seventeen as Endangered, thirty-two as Vulnerable, sixty-four as Lower Risk/Near Threatened, and one as Lower Risk/Conservation Dependent. Critically Endangered means facing an extremely high risk of extinction in the wild in the near future. Endangered means facing a very high risk of extinction in the wild in the near future. Vulnerable means facing a high risk of extinction in the wild. Near Threatened means at risk of becoming threatened with extinction in the future. Conservation Dependent means that if the conservation program were to end, the animal would be placed in one of the threatened categories.

SPOTTED RATFISH

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