PERCHES, DARTERS, AND RELATIVES: Percoidei

PHYSICAL CHARACTERISTICS

Fishes in the suborder Percoidei (puhr-COI-dee-ee) have the following characteristics in common: spines in the dorsal (DOOR-suhl), anal (AY-nuhl), and pelvic fins; two dorsal fins; rough scales; pelvic fins in the chest area; a spine and soft rays, or supporting rods, in the pelvic fin; and no more than seventeen rays in the tail fin. The dorsal fins are the ones along the midline of the back. The anal fin is along the midline of the belly. The pelvic fins correspond to the rear legs of four-footed animals.

GEOGRAPHIC RANGE

Fishes in Percoidei live all over the world except for polar waters.

HABITAT

Fishes in Percoidei live in freshwater or saltwater. The freshwater fishes live in lakes, ponds, ditches, swamps, and fast- and slow-moving streams. Saltwater fishes live near the shore or out at sea.

DIET

Some fishes in Percoidei eat algae, plants, animal plankton, invertebrates, which are animals without backbones, and fish. Algae (AL-jee) are plantlike growths that live in water and have no true roots, stems, or leaves. Plankton is microscopic plants and animals drifting in water.

BEHAVIOR AND REPRODUCTION

Some fishes in Percoidei are active during the day, and some are active at night. Some form schools; others live alone. Some fishes rest on the bottom. Some move up and down in the water. Some fishes travel for spawning, or releasing eggs. Some spawn in groups and scatter their eggs; others build nests to mate. Many fishes guard their eggs and young.

PERCHES, DARTERS, THEIR RELATIVES, AND PEOPLE

Some fishes in Percoidei are caught for food, and some are farmed. Many are prized sport fishes, and many are used in aquariums.

CONSERVATION STATUS

The World Conservation Union (IUCN) lists one species in Percoidei as Extinct, eight as Critically Endangered, eleven as Endangered, fifty-six as Vulnerable, one as Conservation Dependent, and twenty as Near Threatened. Extinct means no longer in existence. Critically Endangered means facing an extremely high risk of extinction in the wild. Endangered means facing a very high risk of extinction in the wild. Vulnerable means facing a high risk of extinction in the wild. Conservation Dependent means if the conservation program were to end, the animal would be placed in one of the threatened categories. Near Threatened means at risk of becoming threatened with extinction in the future.

CIGUETERA

Ciguetera poison comes from a one-cell plant eaten by plankton, which is eaten by fish, which are eaten by other fish. The strength of the poison increases ten times every time it is taken in by a new animal. Humans who eat fish with ciguatera suffer nerve damage that can be fatal.

Ready, Aim, Fire

Archerfish can spit water up to 5 feet (1.5 meters) to knock insects into the water for a meal.

The U.S. Fish and Wildlife Service lists thirteen species as Endangered and seven as Threatened. Endangered means in danger of extinction throughout all or a significant portion of its range. Threatened means likely to become endangered in the near future.

LARGEMOUTH BASS (Micropterus salmoides): SPECIES ACCOUNTS

Physical characteristics: Largemouth bass reach a length of about 38 inches (97 centimeters). The mouth is so large it extends back past the eyes. These fish are light green to light brown on the back and upper part of the sides and white on the lower sides and belly. A dark stripe runs along each side of the body.

Geographic range: Largemouth bass are native to the eastern half of the United States and southern Canada but have been introduced worldwide.

Habitat: Largemouth bass live in lakes, ponds, and rivers that have many hiding places.

Diet: Largemouth bass mainly eat crustaceans and fishes. Crustaceans (krus-TAY-shuns) are water-dwelling animals that have jointed legs and a hard shell but no backbone.

Behavior and reproduction: Adult largemouth bass live alone. The young form schools. At spawning time males become territorial and dig a nest in a weedy area at the bottom of the water. A female may lay eggs over several nests. Both males and females guard their eggs and young.

Largemouth bass and people: Largemouth bass are popular sport fish.

Conservation status: Largemouth bass are not threatened or endangered. ∎

COMMON DOLPHINFISH (Coryphaena hippurus): SPECIES ACCOUNTS

Physical characteristics: Common dolphinfish are about 83 inches (2 meters) long. Males have a high, block-like forehead, but females have a rounded forehead. The dorsal fin extends from head to tail. The anal fin extends from the center of the body to the tail. The tail fin is deeply forked. Dolphinfish are brilliant metallic green and blue on the back and upper sides, gold on the lower sides, and yellow and white on the belly.

Geographic range: Common dolphinfish live in the Atlantic, Pacific, and Indian oceans.

Habitat: Common dolphinfish live in open water near the surface but sometimes go near shore to look for food.

Diet: Common dolphinfish mainly eat smaller fish and squid.

Behavior and reproduction: Common dolphinfish form traveling schools. They are attracted to boats and floating objects. These fish can reproduce when they are only four to five months old. They release free-floating eggs in open water, and the eggs hatch in about thirty-six hours. Common dolphinfish live for about five years.

Dolphinfish and people: Common dolphinfish are highly prized for food and sport. They can cause ciguatera (see-gwuh-TEHR-uh), a form of food poisoning.

Conservation status: Common dolphinfish are not threatened or endangered. ∎

GOLDEN PERCH (Macquaria ambigua): SPECIES ACCOUNTS

Physical characteristics: Golden perch reach a length of 30 inches (75 centimeters) and a weight of 53 pounds (24 kilograms), but most are smaller. They are olive green, bronze, or brownish and have a yellow belly. The body is somewhat broad from back to belly and narrow from side to side. The pelvic fins have long strings.

Geographic range: Golden perch live in Australia.

Habitat: Golden perch live near fallen or submerged trees, overhanging banks, and rocky ledges in muddy, slow-flowing rivers and clear, fast-flowing rivers.

Diet: Golden perch eat crustaceans, mollusks, and fish. Mollusks (MAH-lusks) are animals with a soft, unsegmented body that may or may not have a shell.

Behavior and reproduction: Golden perch live alone. Females can reproduce when they are four years old, males when they are two years old. Golden perch travel more than 1,200 miles (2,000 kilometers) to reach their spawning grounds. Eggs float after spawning and hatch in a little more than a day. The larvae drift downstream.

Golden perch and people: Golden perch are mainly game fish.

Conservation status: Golden perch are not threatened or endangered.

BANDED ARCHERFISH (Toxotes jaculatrix): SPECIES ACCOUNTS

Physical characteristics: Banded archerfish are silvery white and have five black bands across the upper sides of the body, the dorsal fin, and the tail. There is yellow on the fins. The body is broad from back to belly. These fish grow to a length of about 8 inches (20 centimeters).

Geographic range: Banded archerfish live in India, Southeast Asia, and Australia.

Habitat: Banded archerfish live in bays and the parts of rivers and creeks that are closest to the sea.

Diet: Banded archerfish eat insects and floating fruits and flowers.

Behavior and reproduction: Banded archerfish live alone or in small groups around shelter. They swim slowly as they hunt for food both below and above the surface of the water. Banded archerfish spawn in pairs and release eggs near the bottom. The larvae (LAR-vee), or young, float in open water.

Banded archerfish and people: Banded archerfish are mainly used in aquariums.

Conservation status: Banded archerfish are not threatened or endangered. ∎

NASSAU GROUPER (Epinephelus striatus): SPECIES ACCOUNTS

Physical characteristics: Nassau groupers have a thick body with a sloping forehead and large fins. The third spine of the dorsal fin is the longest. The body is light brown in shallow water and pinkish brown or red in deeper water. There are dark and pale bands along the sides and the dorsal fin. A dark saddle on the upper part of the tail and dark spots around the eyes are present no matter what color the rest of the fish is. Nassau groupers grow to a length of about 47 inches (120 centimeters).

Geographic range: Nassau groupers live in the western part of the Atlantic Ocean from Bermuda to northern Brazil.

Habitat: Adult Nassau groupers live in coral and rocky reefs. The young usually live in sea grass beds.

Diet: Nassau groupers mainly eat crabs and large mollusks.

Behavior and reproduction: Nassau groupers can change color rapidly, from dark to light shades. They usually live alone, although they may form groups for spawning. They ambush their prey. Nassau groupers can reproduce when they are four to eight years old and function first as a female and then as a male. They spawn in open water in large groups. The eggs and larvae float in open water.

Nassau groupers and people: Nassau groupers are important food and game fish. They can cause ciguatera in humans who eat this fish. They also are collected for large aquariums.

Conservation status: The World Conservation Union (IUCN) lists Nassau groupers as Endangered. Endangered means they are facing a very high risk of extinction in the wild. ∎

FOR MORE INFORMATION

Books:

Gilbert, Carter Rowell, and James D. Williams. National Audubon Society Field Guide to Fishes: North America. New York: Knopf, 2002.

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

Schultz, Ken. Ken Schultz's Field Guide to Freshwater Fish. New York: Wiley, 2004.

Schultz, Ken. Ken Schultz's Field Guide to Saltwater Fish. New York: Wiley, 2004.

Web sites:

"Lesson 1: Refraction at a Boundary—The Secret of the Archer Fish." The Physics Classroom. http://www.physicsclassroom.com/Class/refrn/U14L1f.html (accessed on October 26, 2004).

"Mahimahi (Coryphaena hippurus)." Oceans Alive. http://www.oceansalive.org/eat.cfm?subnav=fishpage&group=mahimahi (accessed on October 26, 2004).

"Nassau Grouper (Epinephelus striatus)." Oceans Alive. http://www.oceansalive.org/eat.cfm?subnav=fishpage&fish=38 (accessed on October 26, 2004).