NATURAL HISTORY OF THE SANDBAR SHARK, EULAMIA MILBERTI 



By Stewart Springer, Fishery Methods and Equipment Specialist 

 Bureau of Commercial Fisheries 



This account of the sandbar shark, Eulamia 

 milberti ( Miiller and Henle) , is an attempt to bring 

 together all the significant information on one 

 kind of common and moderately large shark. 

 Sharks have been studied because they are occa- 

 sionally dangerous to man, often a nuisance to 

 fishermen and, in the past at least, have been 

 valuable as a source for food, leather, vitamin A, 

 fish meal, and some specialty products. A rather 

 comprehensive body of knowledge exists about 

 some of the smaller species, such as the compara- 

 tively valuable soupfin shark of the coast of 

 North America (Ripley, 1946) and the school 

 shark of Australia (Olsen, 1954), botli si)ecies of 

 Galeorh'mus^ and the common spiny dogfish, 

 Squalus (Ford, 1921; Hickling, 1930; Temple- 

 man, 1944). Information on the natural history 

 of the larger species is fragmentary. This is to 

 be expected, because large species not only are 

 difficult to catch and handle, but also are far- 

 ranging and require observation over a wide geo- 

 graphical area. 



The sharks, together with their relatives, the 

 skates, rays, and chimaeroids, form a class of 

 vertebrates that is sharply set off from the classes 

 which contain the fishes, amphibians, reptiles, 

 birds, and mammals. The sharks and other mem- 

 bers of the class Chondrichthyes have cartilagi- 

 nous skeletons, and wliile elements of the shark 

 skeleton may become calcified, no true bone is 

 formed. This is the basis for the definition that 

 is generally used to distinguish the Chondrich- 

 thyes from the higher vertebrates. But there are 

 other differences in the chemistry and physiology 

 that are very likely of great importance but are 

 little understood. The evolutionary connections 

 of the modern sharks and their allies with other 

 modern vertebrates are obscure and of great an- 

 tiquity. 



Note. — Approved for publication, October 27, 1958. Fishery 

 Bulletin 178. 



Sharks occupy a place in nature at the top of 

 tlie food chain. As predators they compete with 

 man, but it is by no means established that their 

 predatory activities ai'e always harmful. They 

 are a nuisance or are harmful to fishermen chiefly 

 because of the damage they do to nets or to fish 

 that have been caught on setlines. In some locali- 

 ties, in England and Australia, for example, 

 sharks are utilized and are consequently of some 

 value. In the United States, landings at present 

 are of no great importance. 



Sharks may be dangerous to man through at- 

 tacks on swimmers and survivors of marine dis- 

 asters, but EuJamia milberti is not a species 

 implicated in well-documented records of attacks. 

 There may be several reasons for this. E. milberti 

 ordinarily stays away from beaches and does not 

 often feed at the surface. It usually seeks small 

 prey. During the summer, when the female sand- 

 bar sharks come inshore near the heavily popu- 

 lated centers from New York southward along 

 the Atlantic coast to give birth to their young, 

 it is not their habit to seek food. The large males 

 do not come inshore. So the sandbar shark, while 

 large enough to be dangerous and perhaps the 

 most common of the larger sharks in shore waters 

 .southward from New York, is isolated by its 

 habits from encounters with man. Nevertheless, 

 the sandbar shark is potentially dangerous to man 

 and might become a more serious danger with 

 minor shifts in the environmental situation. 



The most annoying aspect of my work with 

 sharks, prior to the publication in 1948 of the 

 first volume of Fishes of the Western North At- 

 lantic on sharks by Dr. Henry B. Bigelow and 

 "William C. Schroeder. was that many we.'^tern 

 Atlantic sharks could not be identified with con- 

 fidence because of a scattered literature of vary- 

 ing (]iiality. It is ai)]iroi)riate (liat I acknowledge 

 tlie importance of this excellent general work to 

 me, because without it ;uul witlioiit the encourage- 



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