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Sharks

More than twenty-five species of sharks are known to live in the Santa Barbara Channel. Some spend their entire lives here, while others, such as the scalloped hammerhead shark, are only occasional residents.

The largest shark in the channel is the basking shark. Stretching up to 45 feet in length, the basking shark is the world's second-largest fish; only the whale shark, which lives in tropical waters, is bigger. Basking sharks often appear in pairs or in groups at the surface of the channel, their tall triangular dorsal fins slicing through the rolling swell. They swim in circles with their cavernous mouths propped open to capture zooplankton and small fish.

Other sharks found in the channel great white sharks, which migrate near shore, pausing at sea lion rookeries in search of prey, and blue sharks, which generally live offshore. They sometimes travel inshore at night to feed on anchovies and squid. Swell sharks inhabit rocky areas of the channel. To protect themselves from predators, they take in large gulps of water, expanding their bodies so that they become lodged into crevices and cannot be pulled out.

What makes a shark a shark? The world's 250 known species of sharks have only a few characteristics in common. They are vertebrate animals with skeletons made of cartilage, a translucent elastic tissue, rather than bone. They live in the water and breathe via five to seven gill openings, and they have special skin that is covered with dermal denticles, tiny tooth-like scales embedded in the skin.

Rays such as the manta. ray and the Pacific electric ray are closely related to sharks, but they lack gill slits and have pectoral fins that are attached to their heads. They propel themselves through the water by flapping their pectoral fins, while a shark depends on the movement of its body and tail for locomotion.

Most sharks are carnivores that eat large prey, except for the two largest sharks, which, paradoxically, feed on microorganisms and small crustaceans strained from sea water. Depending on the species, sharks are born in one of three ways: they hatch from eggs, like most other fish; or they are born alive, as in the case of the basking shark; or they hatch from eggs within the uterus.

Sharks do not possess noses for breathing, but they do have nostrils that provide them with a keen sense of smell. Many shark experts maintain that this sharp olfactory sense is more important than vision in guiding them to their prey. Shark watchers disagree about how well sharks can see. They are clearly not dependent upon vision for detecting changes in their environment, for they seem to be aware of such things as water temperature and salinity. Using their pores as detectors, they can also sense changes in the surrounding electrical field.


Except for man, the shark's only true adversary is another shark. Other animals, such as dolphins, may be smarter, but they are still no match for the shark, which is equipped with an effective arsenal for destruction: strong teeth and an abrasive hide, backed by powerful momentum.

Scientists once characterized sharks as cowardly scavengers who wouldn't attack an injured human. Now they believe that sharks do attack even when not provoked, although this happens less often than Hollywood would lead us to believe. Shark attacks, especially in shallow coastal waters, are rare and when they do occur, most injuries are survived.

Scientists estimate that less than half of all shark attacks are motivated by hunger. An attack is sometimes a case of mistaken identity. The silhouette of a surfboard viewed from below bears a close resemblance to a swimming sea lion. A wet suit, which enables a diver to swim in colder waters more hospitable to sharks, also gives a human the look of a sleek marine mammal such as a dolphin or a seal. In other cases, a shark may attack to defend its territory, or because the human is unfamiliar, or because it perceives the human as interfering with courtship or pupping

Between 1926 and 1984, only one shark attack was reported in the channel region; it was attributed to a great white shark. In 1989, a diver reported being attacked by a blue shark midway between Anacapa and Santa Barbara Islands while participating in a photographic expedition. The diver, who was swimming outside a protective cage when the shark attacked, had poured fish oil and mackerel blood into the water to lure sharks into a feeding frenzy. Thus, the authorities considered this a provoked incident rather than an attack.