As ocean temperatures become pleasant for swimming in Southern California, and visitors pack the beaches, it's a good time to review stingray safety.
1) How to avoid stingrays? The stingray shuffle.
Shuffle or drag your feet along the bottom to scare away stingrays, says Captain Joe Bailey with the Seal Beach Lifeguards in Orange County.
You don't want to sneak up on a stingray because its response will be to keep still and stay hidden, says Chris Lowe, a marine biology professor with California State University at Long Beach, who has had USC Sea Grant support to study rays.
2) How should you treat a stingray sting? Soak the injured area in hot, but not scalding, water.
Lifeguards often have buckets of hot water at their stands, just for this purpose – one more reason to swim at beaches with lifeguards.
Dr. Richard Clark, director of the division of toxicology at UC San Diego Medical Center, recommends soaking the injured area for about 15 minutes. The ideal water temperature is warmer than a hot tub (104 degrees), but less than 114 degrees.
If you are still in a lot of pain after 15 minutes, he recommends seeing a doctor or going to an emergency room. At the doctor's office, expect to have X-rays taken because, on rare occasions, part of the stinger can break off. You may also be given a tetanus shot.
Dr. Clark also often puts patients on antibiotics, not to treat the sting, but because of water-borne bacterial pathogens, the main worry being Vibrio, which can be present in coastal waters.
3) Why hot water? It neutralizes the toxin.
Dr. Clark says that the venom in the stingray is heat labile, meaning heat denatures and destroys the toxin that causes inflammation and pain.
4) Are all rays dangerous? No, and the animals are not aggressive, either.
Most injuries in Southern California are from round rays, Lowe says. Small bat rays have also been known to sting people, though this is much less common.
5) What is the "sting" from? The stinger is coated in a venomous mucous sheath.
The mucous sheath contains toxin cells that rupture upon impact, says Lowe, whose research has examined the topic. Grooves on the barb - a modified dermal scale - help with toxin delivery.
6) Why does it hurt so much? Nobody really knows.
There is something about the venom that stimulates the pain receptors in our body, Dr. Clark says. The exact toxin is not yet well understood, but it's likely a complex mixture of different chemicals, similar to the venom on the spines of scorpion fishes, which include most of the world's venomous marine fishes.
Video: Round stingrays like this one will bury themselves in the sand in shallow water.
This makes it easy to step on one. Video by Catherine Courtier
Written by Christina S. Johnson (2012). Updated 2019