There are about forty species of sharks found in Hawaiian waters, ranging in size from the deep-sea pygmy shark (about 8 inches) to the whale shark (up to 50 feet or more).
Species close to the coast
About eight species are somewhat common in waters near the coast. The most frequent are the white tip reef, the sandbar, the scalloped hammer and, occasionally, the tiger.
These coastal species are high-level carnivores, feeding mainly on fish. Their functions in reef ecosystems are not fully understood, although they can control the size of the fish population and eliminate sick and injured fish, leaving the healthiest ones to survive and reproduce.
Well-developed sensory skills
Sharks have extremely well developed sensory abilities. They can detect sounds and smells from prey at great distances (up to a mile or more, depending on water conditions). Your eyesight is good, but it is highly dependent on the clarity of the water.
When sharks get close to their prey, they can detect the weak electric fields emitted by all living organisms. Receptors in their snouts, known as Lorenzini blisters, allow sharks to locate their prey without seeing them.
Using these and other senses, sharks can find prey at dusk, night, and dawn, which is when some coastal species are generally believed to forage.
A threat to swimmers?
Sharks are very in tune with their environment. They know when people are in the water long before people are aware of them. Shark-human encounters are rare, and most coastal species pose little threat to humans.
Although any shark can be potentially dangerous, especially if provoked, only a few species of Hawaiian sharks are believed to have been responsible for biting people. However, many coastal species are difficult to distinguish from each other, and positive identification is often not made.
Tiger sharks pose the greatest danger
In cases where the offending shark can be identified, tiger sharks top the list. A tiger shark is easily recognized by its blunt snout and vertical bars on its sides. Hammerhead sharks are also easy to identify and have been implicated in some cases where they may have been provoked.
Tigers are considered the most dangerous sharks in Hawaiian waters. White sharks, which are also very dangerous, are rarely seen in Hawaii. Due to their size and feeding habits, tigers occupy the highest niche in coastal feeding relationships.
For years, tiger sharks were believed to be territorial in nature. People were thought to stay for the most part in a fairly limited area. Recent evidence suggests that this is not the case. Tiger sharks have been found to navigate between the main Hawaiian islands and therefore appear to occupy much larger home ranges than previously suspected.
Tiger sharks are often attracted to the mouths of streams after heavy rains, when highland fish and other animals are washed out to sea. They can easily locate prey in those murky waters. Tigers are also attracted to the waters frequented by fishing boats, which often carry fish debris and blood.
Of all the coastal species, tiger sharks have the most varied diet. They eat fish, lobsters, birds, turtles, dead animals, even garbage, and can feed as long as there is a food source.
It is not known why tiger sharks sometimes bite humans. The evidence that a person is mistaken for an object of natural prey, such as a turtle, is not supported by any evidence. The shark may be trying to determine if a person is a possible prey object, it may encounter a person while in a feeding ‘mode’, or there may be some other explanation.
Attacks on humans are rare
Shark incidents stinging people in Hawaiian waters are very rare, occurring on average at a rate of about three to four per year. Fatal shark bites are extremely rare, especially considering the number of people in Hawaiian waters.
People entering the water must recognize that there are hidden dangers. Various marine animals can cause serious injury to people, and sharks are just one example. Entering the ocean should be considered a “desert experience”, where people are visitors in a world that belongs to sharks.
The risk of injury from sharks is extremely small, but it is an accepted risk for anyone entering the world of sharks. By learning more about sharks, using common sense, and observing the following safety tips, your risk can be greatly reduced.
