When Australian wildlife expert Steve Irwin died last week of a stingray spine puncture to the heart, it raised the issue of just what the danger of rays are to Hawai'i oceangoers.

The first answer is that the chances of injury from a ray are minimal, since rays are uncommon in Hawaiian waters. The biggest of the Hawaiian rays is not a risk at all. The manta ray, or hahalua, can get huge — wingspans have been measured at more than 20 feet—but it's not dangerous. These are the rays that approach the lights at the old Mauna Kea Beach Hotel, where some people swim with them.

The spotted eagle ray, which goes by the generic Hawaiian ray names of lupe or hihimanu, is dark with white spots. It is shy around humans, but its spine or spines can cause injury if you handle them, says the book "Sharks and Rays of Hawai'i" by Gerald Crow and Jennifer Crites. The creature's wingspan can reach 6 feet.

The brown stingray can be 5 feet wide, has a venomous spine and does occasionally come into shallow water. "Sharks and Rays of Hawai'i" suggests the main danger is stepping on an immature ray buried in sand in shallow water. They have a very dark brown to black back.

The diamond stringray, can grow to be 3 feet wide and has a venomous tail spike, but is rarely seen.

The spines of stingrays lie flat against the tail, but the ray can extend them up if it feels threatened. The spines are bony and barbed, and can break off in the wound if a ray snaps its tail into the victim. The stinger can cause infection, and the venom can cause severe discomfort, and in some people can cause more severe systemic symptoms. Craig Thomas and Susan Scott's book "All Stings Considered" says that venom is released in two-thirds of stingray injuries. Severe punctures require medical attention, to remove pieces of stinger and to deal with the effects of the venom.

"Stingray spines can easily penetrate rubber or neoprene shoes. Stingrays have punctured the sides of wooden boats," they write.

Marine scientist Jim Luecke, assistant curator of exhibits at the Maui Ocean Center, recommended doing "the stingray shuffle" when walking on sand in shallow water, since the vibrations will generally frighten buried rays into fleeing.

The torpedo ray, sixgill stingray, giant stingaree, spinetail devil ray and the pelagic or violet stingray are around Hawai'i but are seldom seen. "I typically tell people that generally these types of rays are found in deeper water than people are," Luecke said.

If you have a question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766 or jant@honoluluadvertiser.com. Or call him at (808) 245-3074.