The Spiny Dogfish (cação-bagre): Description of an Envenoming in a Fisherman, with Taxonomic and  Toxinologic Comments on the Squalus Gender.

Haddad Jr, V.;^1,2 Gadig, O. B. F.³

1 Faculdade de Medicina, Universidade Estadual Paulista, Botucatu, SP, Brasil; 2 Hospital Vital Brasil, Instituto Butantan, SP, Brasil; 3. Curso de Biologia Marinha, Universidade Estadual Paulista, São Vicente, SP, Brasil. 

Introduction: Toxinology studies on envenoming caused by elasmobranchs report, mostly, cases   associated to stingrays of Myliobatiform Order. The reports of envenoming provoked by sharks are rare. Methodology and conclusions: we report a envenoming occurred in Ubatuba (North Coast of São Paulo State). The victim, male, 54 years-old, professional fisherman, resident in Ubatuba, after to handle a dogfish (cação-bagre) of Squalus gender was got hurt in the left hand with the spine of the dorsal fin of the fish, near to the fifth finger. Immediately, he felt intense pain in the point of the wound, which decreased about four hours, without treatment. The point of puncture of the spine presented erythema and edema. The edema remained for approximately two weeks, with local cutaneous queratosis. The sharks of the Squalus gender, in a similar way to the of the gender Heterodontus, present two spines of triangular format and convex sides, each one in position previous to the dorsal fins. These spines present ducts in their exposed portion, turning the extremities almost hollow. The duct presents a whitish mass, composed of vacuolated cells that produce venom. The envenoming causes intense pain, erythema, edema, irradiation of the pain to the axila or groin and muscular weakness mainly in fishermen that try to remove the fish of fishhooks and nets  (HALSTEAD, 1988; HADDAD Jr, 2000), facts that coincide with the case described. Of the taxonomic point of view, the Squalus gender is complex, with five nominal species mentioned in Brazil: S. acanthias, S. blainvillei, S. cubensis, S. megalops and S. mitsukurii (Gadig, 2001). The first of them, composed by S. acanthias, it is the only species positively identified in Brazil. The species associated to the injury belongs to the group "megalops/cubensis” (Marques, 1999). A detailed study on the taxonomy of the Squalus gender in Brazil would be of vital importance in the resolution of those problems and it would serve as subsidy for any other works involving their representatives, besides with aspects of poisonings that this gender can cause and that has rare citations in the literature.

Correspondence to: haddadjr@fmb.unesp.br