154 UNDERWATER GUIDE TO MARINE LIFE 



Fig. 62. Blue shark. 



BLUE shark: Prionace gJaiica 



Size: Commonly 9 to 12 feet. Rarely to 20 feet. 



Weight: 164 pounds at 9 feet. 



Distribution: Cosmopolitan in warm temperate and tropical seas. North to 

 British Columbia in the Pacific and Nova Scotia in the Atlantic. Not found 

 in shallow-water areas such as the Gulf of Mexico. 



Identification: The coloration is a beautiful indigo blue, fading to pure white 

 below. The body is slim, the pectorals very long, and the snout very long and 

 pointed. The first dorsal is rather far back for a requiem shark. 



Habits: This is the most common pelagic shark, held in fear by sailors and 

 in contempt by whalers. It is normally sluggish except when aroused. There are 

 few recorded attacks by this species on man, but it should not be counted as 

 harmless. It is most commonly seen at the surface, basking with the dorsal fin out 

 of water or following after ships in search of food. For the latter reason, they 

 have been named chiens de mer by the French. When hunting prey, they are 

 active and have been observed to repeatedly blink with the third eyelid. They 

 are most active at night. The blue shark's greed is practically legendary. It feeds 

 on all sorts of small pelagic fishes and squids. Frequently, it gathers in great 

 numbers about whaling ships to share in the carcass. At such times, when the sea 

 is clouded by blood, the sharks flounder all about the whale. Occasionally, the 

 whalers strike the sharks with their blubber spades and horribly mutilate them, 

 but even when so wounded, they go right on feeding until some of their fellows 

 dispose of them. There is a record of one captured blue shark, which had had its 

 liver removed, trying to catch a mackerel after being thrown back in the water. 

 Another gutted blue shark was recaught on a hook baited with its own intestines. 

 This shark is viviparous and rather prolific, producing as manv as fiftv-four pups 

 at almost any time of year. 



LEMON SHARK (yellow shark) : Ncgaprion brevirostris 



Size: Matures at 7 feet. To 1 1 feet rarely. 



Weight: 265 pounds at 9Vi feet. 



Distribution: Cape Hatteras to Brazil. Most abundant in the Caribbean. Also 

 in the South Pacific and Indian Oceans. 



Identification: The first dorsal is small for a requiem shark and the second 

 dorsal rather large. The color is yellowish brown, fading to a distinct yellow 

 on the underside. The snout is broad and rounded. 



