Fishes of the Western North. Atlantic 



1 1 



The largest of the batoids thus feed in essentially the same manner as do the Basking 

 Shark and the Whale Shark. 



Relation to Man. The Skates (Rajidae) are of considerable value to the fishermen 

 of Europe, as described on p. 145. But they are in little demand elsewhere. None of the 

 other batoids are of any great commercial importance, for while Rays in considerable 

 variety are brought in to fish markets in tropical ports in various parts of the world, 

 the number involved is small. A minor use has been made of the spines of Sting Rays 

 to tip spears or to arm the lashes of whips, as described later (p. 338). The large Devil 

 Rays are pursued to some extent with the harpoon as objects of sport. Otherwise, the 

 chief importance of Rays to fishermen is their nuisance value, some of them because 

 they take the baits intended for better fishes (p. 145) and others because of the injuries 

 they are capable of inflicting by their serrate spines on anyone who may handle them 

 incautiously or who may tread on them while wading on flats in regions where they 

 are plentiful (p. 336). 



Habitat and Range. The latitudinal range of the batoids as a group extends from 

 the Equator to the subpolar belt in both hemispheres, and their distribution is equally 

 wide in all three great oceans, Atlantic, Pacific, and Indian, including the tributary 

 seas. Nor can the group as a whole be described as chiefly characteristic of any par- 

 ticular latitudinal zone. While the most numerous group of all (Rajidae) has reached 

 its maximum development (whether as to species or as to number of individuals) in 

 the temperate-boreal belts of the two hemispheres, the Sting and Butterfly Rays and their 

 kin (Dasyatidae, Gymnuridae, Urolophidae), the Eagle and Cow-nosed Rays (Mylio- 

 batidae, Rhinopteridae), the Devil Rays (Mobulidae), the Sawfishes (Pristidae), and 

 the Guitarfishes (Rhinobatidae, Rhynchobatidae) are more numerous in tropical and 

 subtropical waters, with the Electric Rays as a group occupying an intermediate position. 



A similar ecological cleavage appears with regard to the range in depth between 

 the Skates (Rajidae) and certain Electric Rays on the one hand and all other batoids 

 on the other. The latter, so far as is known, are most abundant by far in shoal water. 

 But the Electric Rays range from close to the tideline down to at least 500 fathoms, 

 while the Skates not only extend down to 1,500 fathoms but are extremely abundant 

 at depths (20-100 fath.) at which the great bottom fisheries of northern Europe and 

 eastern North America are chiefly carried on (p. 144). It has been discovered-^ recently 

 that the bottom along the north coast of Cuba, at depths of 200-500 fathoms, sup- 

 ports an abundant community of Skates, several species of which have not been found 

 elsewhere. Even more recently we have found that there exist in the Gulf of Mexico, 

 in depths of 50-300 fathoms, some additional species which are new to science (pp. 

 286, 314). 



Consequent on their wide distribution both in latitude and depth, the batoids 

 cover nearly as broad a thermal range as do the bony fishes, i. e., from the highest tem- 

 peratures to which the water warms over the shallows in tropical estuaries to polar 

 waters that may be as cold as -1.5° C (about 29° F). However, only one species {Raja 



2z. Bigelow and Schroeder, J. Mar. Res., 7, 1948: 543. 



