Milkfish and Relatives: Gonorynchiformes
Milkfish (chanos Chanos): Species Account
Physical characteristics: Milkfish can reach a length of about 6 feet (1.8 meters) but usually are about 5 feet (1.5 meters) long. Adults are silvery and have a forked tail, large eyes, and a pointed snout. They have a special pouch in the digestive tract for sifting plankton. The jaws are toothless. The dorsal (DOOR-suhl) fin, the one along the midline of the back, has thirteen to seventeen rays, or supporting rods; the anal (AY-nuhl) fin, the one along the midline of the belly, has six to eight rays; the pectoral (PECK-ter-uhl) fins, the front pair, have fifteen to seventeen rays; and the pelvic fins, the rear pair, have ten or eleven rays. Four or five rays support the gill covering on each side behind the head.
Geographic range: Milkfish live throughout the Indian and Pacific oceans.
Habitat: Adult milkfish live in the open ocean. Larvae (LAR-vee), or the early stage that must change form before becoming an adult, live in inland ponds that have a salt content slightly less than that of seawater.
Diet: Milkfish larvae eat animal plankton. Adults eat bacteria, algae, small bottom-dwelling invertebrates (in-VER-teh-brehts), which are animals without backbones, and sometimes eat free-floating fish eggs and larvae.
Behavior and reproduction: Milkfish, both young and adults, are schooling fishes. They breed near the shore and release their eggs into open water. When the larvae are about three-eighths inch (1 centimeter) long, they enter water that has a slightly lower salt content than seawater. The young adults return to the sea.
Milkfish and people: Milkfish is one of the most important food fishes in Indonesia, the Philippines, and Taiwan. It is commercially farmed in these areas. The young are caught close to shore and then raised in coastal ponds. Milkfish also is fished extensively throughout its range. Fishermen use cormorants with rings around the birds' necks to catch the fish. The rings prevent the birds from fully swallowing the fish.
Conservation status: Milkfish are not threatened nor endangered. ∎
FOR MORE INFORMATION
Ricciuti, Edward R. Fish. Woodbridge, CT: Blackbirch, 1993.
Schultz, Ken. Ken Schultz's Field Guide to Saltwater Fish. New York: Wiley, 2004.
"Milkfish." All Science Fair Projects. http://www.all-science-fair-projects.com/science_fair_projects_encyclopedia/Milkfish (accessed on September 23, 2004).
"Milkfish." SEAFDEC Aquaculture Department. http://www.seafdec.org.ph/home.html (accessed on September 24, 2004).
Animal Life ResourceFish and Other Cold-Blooded VertebratesMilkfish and Relatives: Gonorynchiformes - PHYSICAL CHARACTERISTICS, GEOGRAPHIC RANGE, HABITAT, DIET, BEHAVIOR AND REPRODUCTION, MILKFISH AND THEIR RELATIVES AND PEOPLE