Venom puts the sting in stingrays

Immerse wound in hot water if you get stung

If there is a fish that saltwater anglers dislike hooking more than a hardhead catfish, it’s got to be a stingray. The presence of the truly venomous sting on their tail means there really is no good way to unhook them.

Plus, fishermen waste a lot of good fishing time trying to get the stubborn fighters to the surface. They are so difficult to retrieve that many anglers maintain (incorrectly) that the rays create “a suction” on the bottom with their pancake-shaped bodies.

Four species of stingrays occur in Louisiana. The most common one encountered by far is the Atlantic stingray. Compared to its cousin, the southern stingray, which grows to 6 feet wing (fin) tip to wing tip, it is a small ray topping out at 24 inches wide.

The Atlantic stingray is relatively easy to separate from the other three Louisiana stingrays, the southern, bluntnose and the yellow. It is the only one in which the nose comes to a sharp point. Color is typically brown to yellowish-brown, fading to a lighter color near the edges of their bodies.

Defining home for the Atlantic stingray

Louisiana is in the heart of the species’ range, which is from Chesapeake Bay southward through most of Mexico. Prime Atlantic stingray habitat is saline and brackish coastal water 6 to 20 feet deep. This species is cold sensitive, and water temperatures below 59°F will trigger migration to deeper, warmer waters.

Atlantic stingrays will also penetrate miles into freshwater rivers such as the Atchafalaya and Mississippi, although they travel back and forth to saltwater. One population, though, has adapted to live permanently in the St. John’s River in Florida 210 miles from the coast.

But permanent freshwater residency comes at a cost. All sharks and rays retain urea in their flesh to balance water pressure in their bodies. (Urea is what gives spoiled shark or ray flesh a wet diaper smell.) Because of the presence of urea, fresh water (but not saltwater) constantly enters the flesh of the rays in the river. To counter bloating, St. John’s River stingrays produce 10 times more urine than do those that live in marine waters.

Atlantic stingrays prefer soft mud or sandy bottoms, into which they will settle to avoid predators. Several species of sharks prey heavily on them. They breathe by drawing water in through spiracles, large holes located on top of their heads behind each eye. The water flows over their gills and out through five pairs of gill slits located on their underside.

The lunch pail

They feed by swimming slowly facing into the current a few inches above the bottom, frequently stopping to rest on the bottom and inspect an area. When prey is detected, the ray uses the undulating movements of its wings (which are really highly modified pectoral fins) to wash away sediments and expose the creature. They will also use their mouths to suck-deep dwelling worms from the bottom.

Foods include amphipods, mole crabs, pistol shrimp, clams, segmented worms and some kinds of starfish. As fishermen well know, they will also jump on any live or dead shrimp attached to a hook.

They can detect prey movement with their lateral line and have a good sense of smell. More importantly, they use electroreceptors called Ampullae of Lorenzini to pick up the weak electrical fields that living animals of any kind give off. Feeding is done almost continuously throughout daylight and evening hours.

Mating teeth? 

Atlantic stingrays have a peculiarity. The males change their choppers in pursuit of love. Females year round and males outside of spawning season have heavy molar-like teeth that are useful for crushing food items.

But for the October to April spawning season, males shed these teeth and grow sharp pointed teeth that are used for mating. When breeding, the male closely follows a female, nipping at her body and fins. Finally, he grabs a wing of the female with his teeth and holds her firmly while he uses his claspers (finger-like fin extensions at the base of the tail) to transfer sperm.

The female produces one to four young per litter in eggs which she retains in her body until they hatch. Each embryo lives off its large yolk sac for 60 days, after which the female nourishes them with a nutritious secretion called uterine milk.

Armed and dangerous

The most notorious feature of the Atlantic stingray is the spine located on top of its tail. It isn’t unusual to find a stingray with two spines, since they replace their spines once a year between June and October, and the old spine stays intact while the new one erupts from the skin.

Females have longer spines than males. The spines are truly venomous, with the venom being produced within the spine’s sheath along two narrow grooves.

The spines are used purely for defensive purposes. An alarmed or trapped stingray, such as one being pinned on the water bottom by a human foot, lashes wildly with its tail. Waders and surf fishermen face the most risk in August, when females move into very shallow water to bear their young.

The slightest cut on a human can cause the affected area and lymph nodes to swell, and the extreme pain alone can send a victim into shock.

First aid measures include letting the wound bleed for a few minutes to flush out some of the poison. The wound should then be thoroughly cleaned and immersed in water as hot as the person can stand for 30 minutes.

Research has shown that stingray venom is very sensitive to heat and breaks down after 15 minutes of soaking. Antiseptic should then be applied, and the victim should see a doctor.

About Jerald Horst 959 Articles
Jerald Horst is a retired Louisiana State University professor of fisheries. He is an active writer, book author and outdoorsman.