SHARKS, RAYS, SKATES, AND CHIMAERAS 



By 



J. R. Thompson and Stewart Springer 



Fishery Methods and Equipnnent Specialists 



Bureau of Commercial Fisheries 



INTRODUCTION 



Sharks, skates, rays, and, to a 

 lesser extent, chimaeras--all grouped 

 by zoologists in the single vertebrate 

 class Chondrichthyes (cartilaginous 

 fishes)--have been the subjects of in- 

 terest for many years. On the negative 

 side, the interest in many of these 

 fishes has arisen largely from fear-- 

 fear of injury to fishermen and 

 swimmers, fear of damage to fishing 

 gear and equipment, and the fear that 

 is a natural accompaniment of a lack of 

 knowledge. On the positive side, the 

 interest has arisen as a result of at- 

 tempts to turn some of these fishes 

 to economic advantage, and out of man' s 

 innate curiosity concerning the world 

 around him. 



Despite widespread interest, ac- 

 cumulation of adequate knowledge con- 

 cerning sharks and their close relatives 

 has been slow, and a large body of 

 speculation and "old wives' tales" has 

 arisen as a result of attempts to fill 

 in the gaps. Obstacles to the study of 

 cartilaginous fishes are many. Most 

 of these fishes are pelagic, and many 

 of them inhabit the open waters of the 

 high seas where large ocean-going 

 vessels are needed for their study. 

 Many species are confined to relatively 

 great depths where collection is dif- 

 ficult and expensive. Even those species 

 that inhabit shallower, coastal water s 

 require special collecting and handling 



Note.— J. R. Tlioiiipson. U.S. Fish and Wildlife Service, 

 Pasca>Joula, Misi.; -ind Stewart Springer. U. S. Fish and 

 Wildlife Service. Washington, D. C. 



techniques. They are difficult to keep in 

 captivity, and their collection and study 

 as living animals is quite expensive. 

 But over the years, zoologists have 

 succeeded in amassing sufficient data 

 to outline, in greater or lesser detail, 

 the characteristics and habits of many 

 of the cartilaginous fishes. 



This paper has been written as an 

 introduction to the members of the class 

 Chondrichthyes. The information con- 

 tained has been dra'wn from the litera- 

 ture, from zoologists and fishermen of 

 many countries, and from the personal 

 experiences and observations of the 

 authors. The purpose of the paper is to 

 answer the many general questions 

 asked fishery zoologists each year 

 concerning sharks, skates, rays, and 

 chimaeras, or if not to ansv/er, at 

 least to suggest further, more detailed 

 sources of information. Toward this 

 end, the text has been kept brief and 

 general, and an annotated list of ref- 

 erences has been included. In most 

 cases, the reader who is sufficiently 

 interested to pursue the subject beyond 

 the confines of this circular will find 

 more material in the references listed. 

 He may also find clues to further re- 

 search sources in the bibliographies 

 contained in the references examined. 

 To facilitate use, the references are 

 listed by topic in an arrangement 

 roughly paralleling the arrangement 

 of the subheadings of the text. 



Terms commonly applied to car- 

 tilaginous fishes and other large marine 



