Ocean Watch

Monday, January 18, 1999

If you see a sea snake,
admire it, but don’t touch

LAST month, someone found a live yellow-bellied sea snake on a Maui beach and called a state biologist. The biologist brought the snake to the Maui Ocean Center where workers discovered damage to the snake's tail. This could have happened from a marine animal bite, a land animal bite after the snake was beached, or from being tossed onto rocks during stormy weather.

In any case, the snake, rare in Hawaii, was treated well. Workers gave the reptile its own tank and tried to feed it.

Despite this special care, however, the snake died three days later. It's too bad. Having a yellow-bellied sea snake on display in a Hawaii aquarium would be a good way for us to learn about, and marvel at, these remarkable marine animals.

Sea snakes are distant relatives of cobras that have adapted to life in the ocean. These air-breathing marine reptiles can stay submerged for about two hours and can dive to about 300 feet.

Sea snakes eat fish, catching prey with a sideways strike of the head. These predators quickly paralyze their prey by injecting a powerful venom through needlelike fangs. The snakes swallow their immobilized meal whole.

At least 52 species of sea snakes, all venomous, are found in the warm waters of the Pacific and Indian oceans. Of these, the yellow-bellied sea snake is the world's most abundant and widespread, spanning the entire tropical and subtropical Pacific Ocean.

Offshore, yellow-bellied sea snakes often float in the marine debris of current lines, preying on the small fish that hide there. Unlike other species, they shun fresh and brackish water, and thus are not found in rivers or estuaries. Also, yellow-bellied sea snakes bear live young. Therefore, they don't come ashore to lay eggs like other snakes.

The yellow-bellied sea snake, the only open-ocean species, is the only one ever seen in Hawaiian waters.

But because the islands are north of these snakes' normal range, sightings here are rare. When they do show up in Hawaii, they are often found tangled in fishing nets or appear sick or dead on a beach.

If you ever get lucky enough to see a sea snake, don't touch it, even if it looks dead. Due to a persistent bite reflex, sea snakes can still bite, and inject venom, up to an hour after death, even after decapitation.

Sea snake venom is among the most potent poisons known to humans. Beaked sea snake venom, a species found in the South Pacific, is the most deadly of all: One drop can kill three adult men. The toxicity of yellow-bellied sea snake venom is about a quarter that of the beaked sea snake, meaning it is still potentially lethal.

Fortunately, no sea snake bites have ever been recorded in Hawaii. Worldwide, the incidence of bites is unclear since most bites occur in areas with little health care and no medical records. One Malaysian study showed that of 120 sea snake bites, over 50 percent occurred to fishermen sorting fish and handling nets.

Sea snake teeth do not penetrate most divers' neoprene wet suits, but may pierce through Lycra or T-shirts. Stories and photos of sport divers capturing and holding sea snakes are common, but this type of bravado is foolish. Even though sea snakes are not aggressive toward humans, the penalty for error is severe.

Yellow-bellied sea snakes grow to an average of 25 to 30 inches long but can reach 44 inches in length. They are black above and, as their name implies, have brilliant yellow undersides.

Report any sighting of a yellow-bellied sea snake in Hawaii to any state wildlife authority. Hopefully, one of these yellow-and-black beauties will survive long enough to be admired in a Hawaii aquarium.