94 Commercial Shark Fishing in the Caribbean Area 



Figure 31 



Family Hexanchidae. 



Genus Hexanchus, Six-Gilled Sharks ; only six gill openings. 



Figure 31. Hexanchus griseus, Six-Gilled Shark; Cow Shark, 

 Mud Shark. 



Description: Front part of trunk fairly thick; snout short and 

 broadly rounded ; eye large ; mouth very large and extending along 

 sides of head ; upper teeth thorn-like with one to three short basal 

 cusps on the outer side ; the first five or six lower teeth much 

 broader with seven to ten short cusps ; the fourth to sixth lower 

 teeth very low, rounded and without definite cusps ; anal fin is 

 similar to the dorsal in size and shape ; the caudal does not have 

 a definite lower lobe and its axis is raised only very little above 

 the main axis of the body ; the margins of the pectoral fins are 

 nearly straight and their corners well rounded. 



Color: Coffee-colored or very dark gray above; a paler shade 

 of the same tint or whitish below. Some specimens have a pale 

 streak along each side. 



Size: This is one of the largest sharks. It is born at a length 

 of 16 to 24 inches and matures at 6 to 6}^ feet, often growing to 

 14 to 15 feet and occasionally even somewhat larger. A 7-foot 

 specimen may be expected to weigh between 300 to 400 pounds; 

 one of 9 feet, between 500 to 550 pounds; one of 13 feet, between 

 1,000 and 1,100 pounds; one of 15 feet about 1,300 pounds. 



Habits: In West Indian waters this shark lives chiefly at depths 

 greater than 75 fathoms and down to more than 400 fathoms. In 

 more northern seas it often comes much closer to the surface. It 

 feeds chiefly on fish — Dolphins, small Marlins and small Swordfish 

 have been found in their stomachs off Cuba. It also feeds on crabs 

 and shrimps. They sometimes bite chunks from other sharks that 

 have been hooked. They bite readily from set lines. The breed- 

 ing season is not known for the Caribbean area. 



Range: Both sides of the North Atlantic, including the Mediter- 

 ranean ; also the Pacific coast of North America (SofTthern Cali- 

 fornia to British Columbia), Chile, Japan, the West Indian ocean 

 and South Africa. It is so far known only from the north coast of 

 Cuba, but since specimens are now being taken frequently there 

 on set lines, fishing at 100 to 400 fathoms, it is to be expected 

 at similar depths throughout the region generally. It is not 

 known to carry out any regular migrations. 



