On Wed, 9 Apr 2003, Charlott Stenberg wrote: Hi list,

I've just read two papers regarding the poisons of, among others, Squalus acanthias and Chimaera monstrosa. Evans, H. Muir. 1920. The posion of the spiny dog-fish. The British Medical Journal Volume 1(1):287-288. Evans, H. Muir. 1923. I. The defensive spines of fishes, living and fossil, and the glandular structure in connection therewith, with observations on the nature of fish venoms. Philosophical Transactions of the Royal Society of London. Series B. Vol. 212:1- 33.

I'm not satisfied with the information I got there. Does anyone know if any recent studies have been made regarding these species "poisons". Also, Dr Evans writes that he treats the patients with "5% solution of > permanganate of potash". Is hot water efficent on elasmobranch poison as well?

Cheers, Charlott - the Goblin Girl

John Bruner on Venom in Sharks and Chimaerids


Charlott's questions as to any recent research on poison glands of sharks and ratfish are very good. As far as I know, there has not been any research done on the posion glands of sharks and ratfish with the exception of an unpublished Master of Science thesis by Goe (1950). The results of which were finally presented in the poisonous fish volume by his supervisor Halstead.

Halstead, B.W. (1970). Poisonous and Venomous Marine Animals of the World. Volume Three - Vertebrates (continued). US Government Printing Office, Washington, D.C.: 1006 pp.

No one has ever examined the molecular structure of the "venom" found in sharks and chimaerids. A few papers have examined the venom from actinopterygians. The partially categorized venom has a subcomponent consisting of prostaglandins. Prostaglandins have been shown to act as sex pheromones in goldfish. It has been shown by Evans (1920) and Goe (1950) the venom gland continues in between the basal supports of the dorsal fin in *Squalus acanthias*. I presented information at the AES meeting in La Paz that the male *Squalus acanthias* statistically have a higher number of basals than the females although the overall area of their dorsal fins are equal in size. I suggested at the meeting that male *Sqwualus acanthias* have a larger venom gland than do the females. I have examined roughly 400 dorsal spines of *Squalus acanthias*. It is my impression that the spines of both male and female *Squalus acanthias* are equally worn. Is it possible the male and female *Squalus acanthias* are using the "venom" as sex pheromones for innoculating each other for sexual reproduction? I have been collecting anecdotical stories of people "stung" by species of *Squalus*. It appears the effects of the venom might be seasonal which might indicate a use of the "venom" for some other purpose than defense.

Also, with respect to treatment of stings by venemous fishes, it is Evans' protocol from his days as a surgeon at Lowestoft Hospital in England which is only partially followed to treat stings, namely soaking in hot water. Evans found if a wound caused by a venomous fish was treated with an injection of the 5% solution of permanganate of potash, it greatly relieved the suffering of the patient and speeded up his recovery. However, a book published in the 1940's on venomous animals got Evans' protocol garbled and suggesting soaking (not injecting with a hypodermic as Evans did) the wound in the 5% solution of permanganate of potash. Physcians soaking the wounds with 5% solution of permanganate of potash found no efficacy and this part of the Evans' protocol has been dropped, lost and forgotten, apparently due to a misquote.

In Edmonton, we have a big ugly shopping mall called West Edmonton Mall. In this mall on display are live sharks, rays, and actinopterygians, some of which are poisonous. I went to the emergency room at the University of Alberta hospital and asked what protocol would be followed if an aquarist was brought into the hospital with a wound from a poisonous fish. They showed me the protocol they would follow which is set down by a medical team in Calgary, Alberta. I contacted this team of experts and asked why the "within the first 24 hours protocol of injection of a 5% solution of permanganate of potash" was dropped from the venomous fish treatment protocol. Their reaction was since I was not a medical doctor I did not know what I was talking about. Now I understand why bloodletting took so long to be stopped.

I would recommend reading the following book:

Evans, Harold Muir (1866-1947) Brain and body of fish; a study of brain pattern in relation to hunting and feeding in fish. Philadelphia, Blakiston, 1940. 164 p. illus., 25 cm. Subjects: Fishes--Anatomy Nervous system--Fishes. Brain QL 639 E92 c.1 Book

Evans presents some of his work on poisonous fishes in a chapter. Evans was told in the 1890's by the Curator of Fishes at the BM(NH) [NOT CHARLES TATE REGAN] that there were no such thing as poisonous fishes. Evans knew better because his younger brother nearly died when he was a boy by the sting of a weeverfish. This stirred Evans to do original research on the venom of poisonous fishes, by taking various glycerine extracts from recently caught *Squalus acanthias* and injecting the extracts into rabbits. You would think there would be money from pharmaceutical companies to pursue this work on venomous fishes, especially since *Squalus acanthias* has become the marine "rat" for experimental research.

Added April 2003. Back to previous page
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