Reply #29: Description: "Stingrays are the largest of the venomous fish..." [View All]

[tiptoe]

Excerpt from:
Attack of the Killer Ray
by Trevor Gardner

http://www.nswseakayaker.asn.au/mag/47/stingrays.html

Stingrays are the largest of the venomous fish, and there are many species in the Australian coastal waters. The tail of the stingray carries at least one barb or spine that may be up to 37 cm long. The barbs are cartilaginous and retroserrate, and covered by a film of venom and mucous contained within an integumentary sheath. Two longitudinal ventrolateral grooves contain venom secreting glands. Stingrays usually lie in the sand on the seabed. When disturbed by pressure over the dorsum of the body, the tail is thrust upward and forward, driving the barb in to the victim. Rupture of the integumentary sheath on penetration allows the venom to be released.
The venom contains toxic proteins. The effects of the venom may be local and/or systemic. Local effects include severe pain at the site of injury and tissue necrosis. Systemic effects include nausea, vomiting, salivation, sweating, respiratory depression, muscle fasciculation, convulsions, cramping abdominal pain, cardiac arrhythmia, myocardial ischaemia and, rarely, death. Many of the systemic effects have been documented only in patients with viscus penetration (gut), and not in those with peripheral stingray injuries.

Local venom effects are usually more troublesome in peripheral stab injuries, but if the barb pierces a vital organ or structure mechanical damage may be more dangerous then the venom effects.

Instances of serious, penetrating, non-cardiac injuries include collection of pus within the chest three days after netting a stingray and sustaining a barb injury to the chest; penetration of the liver; multiple bowel perforations; and laceration of a femoral artery, with death by exsanguination. Penetrating cardiac injuries have generally been fatal. In 1938, an adult women died after a stab wound to the heart by a stingray. The autopsy showed that the ventricles had been completely transfixed by the barb. An Australian soldier died in 1945 after a stab wound to the left heart, sustained while swimming in seawater baths near Melbourne, Victoria.

The current patient was fortunate to have a sustained an injury to the coronary artery rather than the heart muscle. The bleeding artery immediately washed the venom away, whereas injury to the heart muscle is difficult to debride and carries the risk of delayed necrosis and perforation (seen in a 12 year old boy in Queensland in 1989).

Tail and barb of a Yellow Stingray - Urolophus jamaicansis -- Paul Osmond


Stingrays - A Wadefisherman's (wade fisherman's) Nightmare