Barracudas, Tunas, Marlins, and Relatives: Scombroidei

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BARRACUDAS, TUNAS, MARLINS, AND RELATIVES: Scombroidei

BLUE MARLIN (Makaira nigricans): SPECIES ACCOUNTS
ATLANTIC BLUEFIN TUNA (Thunnus thynnus): SPECIES ACCOUNTS
GREAT BARRACUDA (Sphyraena barracuda): SPECIES ACCOUNTS

PHYSICAL CHARACTERISTICS

Barracudas, tunas, marlins, and their relatives have streamlined bodies. They are medium-sized (about 2 feet or 61 centimeters) to huge (16 feet or 5 meters) and are extremely fast swimmers. Some can leap high out of the water. Some of these fishes have nets of tiny blood vessels in their bodies that help them keep cool during their intense physical efforts.

GEOGRAPHIC RANGE

Barracudas, tunas, marlins, and their relatives live all over the world.

HABITAT

Most barracudas, tunas, marlins, and their relatives live in the open sea, usually near the surface. Some live in middle depths, and some live in estuaries (EHS-chew-air-eez), or the areas where rivers meet the sea. One species moves long distances upriver.

DIET

Most barracudas, tunas, marlins, and their relatives hunt for fish, squid, and crustaceans (krus-TAY-shuns), or water-dwelling animals that have jointed legs and a hard shell but no backbone. Some eat plankton, or microscopic plants and animals drifting in water.

BEHAVIOR AND REPRODUCTION

Some barracudas, tunas, marlins, and their relatives form large schools, but others live alone. They all spawn in groups. The eggs float freely and hatch into free-floating larvae (LAR-vee), which are an early stage that must change form before becoming adults.

BARRACUDAS, TUNAS, MARLINS, THEIR RELATIVES, AND PEOPLE

Barracudas, tunas, marlins, and their relatives are important food and sport fishes.

A VALUABLE FISH

The belly meat of bluefin tuna reaches astronomical prices in the Japanese market for sashimi (sah-SHEE-mee), a dish of thinly sliced raw fish. A record price of $173,600 was reached for a 444-pound (201 kilograms) bluefin sold in Tokyo in January 2001.

MORE THAN A FISH STORY

A huge marlin is one of the main characters in The Old Man and the Sea, a famous story about respect and persistence by Ernest Hemingway, who won the Nobel Prize for Literature.

CONSERVATION STATUS

The World Conservation Union (IUCN) lists one species of barracudas, tunas, marlins, and their relatives as Critically Endangered, one as Endangered, and one as Vulnerable. 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.

BLUE MARLIN (Makaira nigricans): SPECIES ACCOUNTS

Physical characteristics: Blue marlins have a long snout that forms a spear. These fish reach a length of approximately 16 feet (5 meters) and weigh more than 1,900 pounds (900 kilograms), almost one ton. The body is blue on the back and silvery white on the belly. There are about fifteen light-colored up-and-down bars on the sides. The forward part of the first dorsal fin is high and pointed. The first anal fin also is large and pointed. The dorsal (DOOR-suhl) fins are the ones along the midline of the back. The anal (AY-nuhl) fins are the ones along the midline of the belly. The tail fin is large and shaped like a crescent moon. The body is covered with scales that are deep in the skin. Each scale has one or two spines.

Geographic range: Blue marlin live in the Atlantic, Pacific, and Indian oceans.

Habitat: Blue marlin live near the surface in the ocean.

Diet: Blue marlin eat dolphinfishes, tuna-like fishes, and squid.

Behavior and reproduction: Marlins use their bills to stun their prey, or animals hunted and caught for food. Scientists know little about the spawning grounds or seasons of blue marlin. The eggs are very small and hatch into free-floating larvae.

Blue marlin and people: Blue marlin is an important food and sport fish.

Conservation status: Blue marlin are not threatened or endangered. ∎

ATLANTIC BLUEFIN TUNA (Thunnus thynnus): SPECIES ACCOUNTS

Physical characteristics: Atlantic bluefin tuna reach a length of 10 feet (3 meters) but usually are about 6 feet (2 meters) long. The body is a symmetrical oval with pointed ends. The back is metallic dark blue, and the lower sides and belly are silvery white. The first dorsal fin is yellow or bluish, and the second is reddish brown. The second dorsal and anal fins are followed by seven to ten tiny fins. The second anal fin is silvery gray, and the small fins that follow it are dusky yellow edged with black. The front of the fish is wrapped in large scales, and the rest of the body is covered with small scales. Tunas have nets of tiny blood vessels that help them stay cool.

Geographic range: Atlantic bluefin tuna live in the Atlantic Ocean.

Habitat: Atlantic bluefin tuna live near the surface in open water.

Diet: Atlantic bluefin tuna eat fish, crustaceans, and squid.

Behavior and reproduction: Atlantic bluefin tuna travel far from their spawning grounds in the Gulf of Mexico and the Mediterranean Sea. Eastern and western Atlantic fish mix, but scientists are not sure how many fish travel all the way across the ocean. Atlantic bluefin tuna can reproduce when they are about four years old. Females weighing about 660 pounds (300 kilograms) produce as many as ten million eggs per spawning season.

Atlantic bluefin tuna and people: Atlantic bluefin tuna are important food and sport fish.

Conservation status: Atlantic bluefin tuna are not threatened or endangered. ∎

GREAT BARRACUDA (Sphyraena barracuda): SPECIES ACCOUNTS

Physical characteristics: Great barracudas reach a length of 79 inches (200 centimeters) but usually are about 51 inches (130 centimeters) long. The body is long and somewhat narrow from side to side. The head is large and has a long pointed snout. The mouth is large, and the lower jaw juts beyond the upper jaw. Great barracudas have strong pointed teeth of unequal sizes in both jaws and in the roof of the mouth. The two dorsal fins are far apart, and the first has five strong spines. The body is deep green to steel gray on the back, silver on the sides, and white on the belly. Adults have angled dark bars on the upper sides and usually have scattered inky blotches on the lower sides toward the rear.

Geographic range: Great barracudas live all over the world except the eastern part of the Pacific Ocean.

Habitat: Adult great barracudas usually live in reefs and offshore areas. The young live in shallow water over sandy and weedy bottoms.

Diet: Great barracudas are fierce hunters of small fish, squid, and crustaceans.

Behavior and reproduction: Adult great barracudas live alone, but the young form schools. Most male great barracudas can reproduce when they are two years old. Females can reproduce when they are four years old. Females spawn several times in one season.

Great barracudas and people: Great barracudas have attacked humans, but most attacks happened because the swimmer was carrying a silvery, bright object, which a barracuda mistakes for prey. Great barracudas are important game fish, but because it can cause a form of food poisoning, the meat is not eaten in most areas.

Conservation status: Great barracudas are not threatened or endangered. ∎