SeaCreatures

TECHNICAL LIBRARY

SEA CREATURES

ALBATROSS

The 3.4 m (11 ft) wingspan of the wandering albatross, one of the largest birds, is an adaptation allowing long-distance flight over vast expanses of open ocean. Generally restricted in their distribution to between 45 and 70 degrees south of the equator, albatrosses feed on crustaceans, squid, and fish during the daylight and evening hours. The wandering albatross lives for up to 30 years and may not breed until the age of 15, when a single egg is laid and incubated for 65 to 79 days.

CORAL

Coral reefs are ecosystems with well-defined structures that involve both photosynthetic plants and consumers . The outer layer of a reef consists of living polyps of coral. Within the coral animals live single-celled, round algae called zooxanthellae. Below and surrounding the polyps is a calcareous skeleton, both living and dead, that contains filamentous green algae. Other species of algae, both fleshy and calcareous, grow in the surface of old skeletal deposits. These algae and other associated plants make up most of the primary producers.
Coral reefs provide thriving ecosystems for numerous species of plants, fish, and other marine life. These photographs depict different types of coral as well as examples of some of the animals that dwell among the coral ridges.

CUTTLEFISH

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Related to the octopus and squid, the common cuttlefish is an open-water species of cephalopod mollusc, which swims by undulating the continuous fin along the length of its short, fat body. The cuttlefish is commercially important throughout many parts of its range. A supporting rod of calcium carbonate present within the cuttlefish, called cuttlebone, is used commercially as a polishing agent and as a source of calcium and salts for captive birds and other animals.

DOLPHIN

The common dolphin, Delphinus delphis, is found world-wide in tropical and warm temperate waters. It travels in schools that sometimes number in their hundreds or even thousands. Females give birth to a single calf about 95 cm (3 ft) in length. Adults grow to 2.5 m (8 ft) in length and 175 kg (385 lb) in weight. Common dolphins can swim at speeds of over 35 km/h (20 mph).

GIANT CLAM

The giant clam, which lives on coral reefs in the Indian and Pacific oceans, is the second-largest extant mollusc, weighing up to 227 kg (about 500 lb) with the shell. The giant clam feeds on marine bacteria. The bright-blue giant clam here has burrowed into the ground, as many clams do.

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HERMIT CRAB

Hermit crabs are distinguished from other crabs by the lack of a shell on the abdomen. As a result, some hermit crabs must find empty snail shells to inhabit. While walking or feeding, these hermit crabs extend their antennae, claws, and two pairs of walking legs from the shell opening. When threatened by predators, they quickly withdraw their bodies back into the protection of the shell. The large claw, the last part of the body to be withdrawn, often acts as a door, closing off the interior of the shell from predators. As these hermit crabs grow, they must continually find new, larger shells in which to live.

HUMPBACK WHALE

Humpback whales feed on invertebrates and fish by lunging rapidly through clouds of prey. They close their mouths around tons of water and prey and then push the water out through about 300 baleen plates that hang from the top jaw and serve as a sieve. They are particularly aerially active, leaping out of the water or slapping the water surface with flippers and tail. These acrobatics are prevalent in the winter mating and calving grounds.

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MANTA RAY

The manta ray, or devilfish, is the largest species of ray, growing to a width of at least 6 m (20 ft) and a weight of more than 750 kg (1,500 lb). In spite of its large size, the manta ray is a filter feeder, straining planktonic organisms and small fish out of the water with its wide, gaping mouth. Unlike other types of rays, the manta ray lacks a spine on its tail.

OCTOPUS

The female white-spotted octopus lays about 150,000 eggs in two weeks, after mating. The young, when hatched, are only about 3 mm long. They live on the surface of the water for about a month, then sink and begin their normal life at the bottom of the ocean.

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EMPEROR PENGUINS

Most species of penguin lay a clutch of two eggs, which are white or greenish in colour. Incubation periods vary according to species. King penguin eggs require more than 50 days of incubation before hatching, whereas jackass eggs hatch in 32 to 36 days. Adult emperor penguins stand guard over a group of chicks, who are covered with down (short, fluffy feathers) until they reach maturity. In general both parents share responsibility for their offspring.

ROCK LOBSTER

Rock or spiny lobsters, sometimes referred to simply as lobsters, lack the enlarged claws of true lobsters. Commercial catches originate largely in the waters off South Africa, Australia, New Zealand, France, Japan, Brazil, Cuba, the United States, Mexico, and the Bahamas. The most important of the commercial lobsters fished off South Africa is the rock lobster Jasus ialandii, shown here. They prefer reefs for shelter, and are found at depths ranging from 5 to 275m (15 to 850 ft).

SEAL

The Antarctic fur seal is one of 14 species of eared seals. Fur seals are polygamous and assemble in huge breeding colonies beginning in October. Breeding females feed exclusively on small shrimp-like crustaceans called krill, while males feed on krill, penguins, and fish. Although most eared seal populations have been decimated by overhunting, the Antarctic fur seal has rebounded from near extinction in the late 1800s to a current population of between 700,000 and 1 million animals.

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SEA SNAKE

The fastest of all sea snakes, the yellow-bellied sea snake can swim at 3.6 km/h (2 mph). It lives in warm waters along the Pacific coast from California to South America. Sea snakes are highly poisonous, but rarely bite people.

SQUID ANATOMY

The squid, a representative cephalopod, shows several variations on the mollusc body plan. The cephalopod's sucker-bearing tentacles are specialized for drawing food into the animal's beaklike jaws. Another cephalopod adaptation is the mantle. Highly muscular, it forces water from the cavity through the tubular siphon to propel the animal quickly through the water. The internal shell is notable - greatly reduced from the large external shells of other molluscs. This shell is entirely absent in octopuses.

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STARFISH

A starfish feeds on coral in the Red Sea. Most starfish have five arms, although specimens with four, six, or more arms are not uncommon. They are known for their ability to regenerate severed body parts.

GREEN TURTLE

An inhabitant of warm sea waters, the green turtle is the fastest-swimming turtle, reaching speeds of up to 32 km/h (20 mph). The green turtle population has declined rapidly after years of being overhunted for its meat.

WHALE SHARK

Strictly a filter feeder, the whale shark strains plankton and small fish from the upper waters of tropical and subtropical seas by lying motionless beneath the water's surface. Considered the largest living species of fish, a whale shark may measure more than 15 m (50 ft) in length and weigh more than 18 tonnes. Whale sharks pose little risk to humans; however, they have been known to ram boats that they have mistaken for rival sharks.

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