Dorsal Fin 



Pectoral Fins 



Gill slits 



Nostril 



Upper lobe. 

 Caudal Fin 



Lower lobe. Caudal Fin 



A"typical" shark, illustrating terms used in description 



sharks are found in much greater 

 depths, although actual captures have 

 not been made as yet in waters deeper 

 than 1,500 fathoms (9,000 feet). There 

 are also several species that inhabit 

 very shallow waters along the coasts. 

 These include some of the dogfishes, 

 small blacktip sharks, hammerheads, 

 nurse sharks, sand sharks, and sand- 

 bar sharks. 



Abundance 



Despite their appearance, at times, 

 in great concentrations, sharks are 

 not normally abundant in comparison 

 with many bony fishes. In the United 

 States the spiny dogfish, one of the 

 smaller sharks, is connmon off the 

 coasts of New England and the Middle 

 Atlantic States in the Atlantic Ocean 

 and off the coasts of Washington and 

 Oregon in the Pacific Ocean. In these 

 areas it is, at times, common enough 

 to be a great nuisance to commercial 

 and sport fishermen. The larger sharks 

 are less abundant. 



Size 



A table on the inside cover of this 

 circular lists the maximum recorded 

 lengths and weights of many of the 

 common species of sharks. Sharks 

 range in size from individuals that 

 mature at a total length of less than 1 

 foot to individuals that do not mature 

 until they are many feet long and that 

 may reach lengths of about 45 feet. 

 One of the smallest sharks known, 

 Squaliolus sp., lives only indeep water 

 and apparently never reaches a length 

 much in excess of 6 inches. The little 

 green dog shark, EtmopteruS ViretlS, 

 from the Gulf of Mexico, is full-grown 

 at a length of about 9 inches, and newly 

 born individuals are about 4 inches 

 long. 



The largest species, by weight, is 

 the whale shark. Another large species, 

 the basking shark, is somewhat less 

 bulky, but about as long. 



