WHALEFISHES AND RELATIVES: Stephanoberyciformes

PHYSICAL CHARACTERISTICS

Most whalefishes and their relatives have a large head with bony ridges that give the fish a highly armored look. These fishes are rarely longer than 10 inches (25 centimeters) and usually are shorter than 5 inches (12 centimeters). The colors usually are drab brown or grayish black, but some fishes are reddish. Many whalefishes and their relatives look velvety because they have small outgrowths on the skin or because they have many spines on their scales. Some fishes in this group lack scales. Others have large, smooth scales. Numerous pores are usually visible on the head and lateral line. The lateral (LAT-uhr-uhl) line is a series of pores and tiny tubes along each side of a fish's body and is used for sensing vibrations. Some species have glowing tissues. All fishes in this group have a single dorsal (DOOR-suhl) fin with very few spines or no spines. The pelvic fins can be well developed, small, absent, or even winglike. The dorsal fin is the one along the midline of the back. The pelvic fins are the rear pair, corresponding to the rear legs of four-footed animals. The tail fin may have spines.

GEOGRAPHIC RANGE

Whalefishes and their relatives live all over the world.

HABITAT

Whalefishes and their relatives live in open water down to about 13,100 feet (4,000 meters). Some species travel close to the surface.

DIET

Little is known about the diet of whalefishes and their relatives. Tiny crustaceans (krus-TAY-shuns) have been found in the stomachs of a few fish. Crustaceans are water-dwelling animals that have jointed legs and a hard shell but no backbone.

BEHAVIOR AND REPRODUCTION

Whalefishes and their relatives travel from deep to shallower water. The reproductive biology of whalefishes and their relatives is largely unknown, but both eggs and larvae (LAR-vee) drift in open water. Larvae are animals in an early stage and must change form before becoming adults. In general, larvae and the young appear to live in shallower water than adults, which live in the deep sea. The larvae of some species have very long streamers on their tails.

WHALEFISHES AND THEIR RELATIVES AND PEOPLE

Whalefishes and their relatives are not eaten. Whalefishes are probably important food for fishes that are caught and sold, such as orange roughy.

CONSERVATION STATUS

Whalefishes and their relatives are not threatened or endangered.

HAIRYFISH (Mirapinna esau): SPECIES ACCOUNT

Physical characteristics: The skin of hairyfish is covered in hairlike outgrowths. These fish have huge pelvic fins that are located near the fish's throat and stick up like wings. The tail fin is divided into two distinct parts that overlap. The single dorsal fin is located far toward the rear of the body. The anal (AY-nuhl) fin is on the belly directly below the dorsal fin. The fish is dark brown.

Geographic range: Only one hairyfish has been caught, and that was in the eastern part of the Atlantic Ocean.

Habitat: The only known hairyfish was caught at the surface.

Diet: Animal plankton was found in the stomach of the only known hairyfish. Plankton are microscopic plants and, in this case, animals drifting in water.

Behavior and reproduction: Scientists do not know anything about the behavior and reproduction of hairyfish.

Hairyfish and people: Hairyfish have no known importance to people.

Conservation status: Hairyfish are not threatened or endangered. ∎

FOR MORE INFORMATION

Books:

Nelson, Joseph S. Fishes of the World. 3rd ed. New York: Wiley, 1994.

Web sites:

"Flabby Whalefish." All Science Fair Projects. http://www.all-science-fair-projects.com/science_fair_projects_encyclopedia/Flabby_whalefish (accessed on October 12, 2004).