Since February, something has been killing Hawaii’s pufferfish. The cause of the deaths isn’t known, but local researchers are working to find it.

Because Hawaii hosts 14 species of pufferfish and four species of porcupine fish, the term pufferfish can mean any one of several shapes, sizes and colors of fish. In general, the fish with sharp spikes on their bodies are porcupine fish, and the ones without, including the little tobies, are pufferfish. I’m using the terms pufferfish and puffers here to mean members of both families.

At least 137 pufferfish species swim in the warm temperate and tropical oceans of the world. All those fish, however, have one trait in common: They can inflate their bellies with water or air. Because of that remarkable ability, members of this group are also known in other parts of the world as blowfish, swellfish or globefish.

Some puffers eat seaweed, and others are scavengers, cleaning the reef of dead animals and waste material.

Mostly, though, pufferfish are carnivores. With strong jaws and teeth that resemble white razor blades, these fish can crunch just about anything they can catch. Since puffers aren’t fast swimmers, their prey is usually of the slow-moving variety such as snails, urchins and coral. Some pufferfish eat crown-of-thorns starfish, an impressive feat because toxic, needle-sharp spines cover these coral-eating starfish.

Marine animals that underestimate pufferfishes’ hunting abilities don’t often get a second chance. Once in the Ala Wai Boat Harbor, I saw an enormous porcupine fish (the largest here grow to 28 inches long) leap from the water onto a half-submerged rock to grab a hand-size aama (black rock crab). The puffer swallowed the crushed crab whole.

Anglers and divers who misjudge the power of pufferfish teeth and jaws might live to tell the story, but their hands are never the same. I once dropped into the Wahiawa ER to see my husband and met a fisherman who was missing the tip of his forefinger. The man had been removing a hook from a pufferfish mouth, and the resulting slice was as straight and clean as a guillotine cut.

Pufferfish expand their bodies with water, or air if the fish is at the surface, to avoid being swallowed. Usually that works because the puffer becomes too large for the predator to get in its mouth.

Some fish, though, die trying. Marlins and some sharks have been found dead with pufferfish lodged in their throats. I don’t know how long pufferfish can survive in those situations, but if found alive and released, these amazing fish simply deflate their bodies and swim away.

In the case of tiger sharks, though, pufferfish lose. Not only are tiger sharks able to swallow puffed up pufferfish, they are also immune to tetrodotoxin, the deadly poison that bacteria manufacture inside the bodies of most pufferfish.

Tetrodotoxin is one of nature’s most deadly poisons. Some people like to tempt death by eating pufferfish in a dish known as fugu, and sometimes death wins. Seven people in Hawaii have died from eating pufferfish.

Researchers who are studying the pufferfish affliction need specimens that are sick or at death’s door. Dead ones decompose too quickly to be studied.

We boaters and beach walkers can help by placing a dying pufferfish on ice or in a bucket of sea water, and calling federal veterinarian Thierry Work at 792-9520 for pickup.

When collecting a pufferfish, remember to keep fingers well away from its bladelike teeth and dogs away from the poisonous body. A pet dog died on Kailua Beach some years ago after biting into a dead pufferfish.

Usually pufferfish are in the news because someone has died from eating one. This time, though, it’s the fish that are dying.

Susan Scott can be reached at www.susanscott.net.