230 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



attains a length of 5 feet, and yields from 1 to 2 gallons of oil ; the 

 leopard or. tiger shark, length from 10 to 25 feet, yielding 10 to 20 gal- 

 lons of oil; the mackerel shark, also known as porbeagle or blue shark, 

 measuring from 8 to 10 feet in length, and the liver yielding from 2 

 to 7 gallons of oil; the dusky shark [Car char Jmius ohscurus), which 

 attains a length of 10 feet; the hammer-headed shark {Spliyrna 

 zygcena), of 12 or 15 feet in length; the dog shark {Mustelus canis), 2 

 or 3 feet in length; and the thresher shai'k {Alopias vulpes). Some 

 of the large sand and leopard sharks are difficult to secure and their 

 capture gives considerable trouble. They are taken usually by means 

 of harpoons or stout hooks and lines. When taken from a small boat 

 at sea, immediately after the fish has been secured it is lanced to 

 death, the belly is ripped open with a knife, the boat canted, and the 

 large, slipper}^ liver pulled over the side into the boat, and then the 

 carcass is discarded. Manj^ of the smaller sharks are captured with 

 menhaden, in j)urse seines, and are utilized at the menhaden fac- 

 tories. Owing to the damage which they do to the twine, the fisher- 

 men prefer to not set the seines around sharks, but it is difficult to 

 avoid taking a few of them with the menhaden. It is estimated that 

 from 7,000 to 10,000 sharks are cajptured annually by the menhaden 

 steamers, all of which are converted into oil and fertilizer. 



On the Pacific coast of the United States, especially in California, 

 the oil shark {Galeorhinus) is utilized. It is 4 to 6 feet in length and 

 weighs from 40 to 70 pounds, the yield of oil from, the livers varying 

 from two -thirds of a gallon to 1 gallon each. The fish are taken by 

 means of hooks and lines when they enter the lagoons for reproduc- 

 tive purposes during the summer. The fins of this species are dried 

 and sold for 12 or 15 cents per pound, the Chinese using them in 

 soui^-making. Other species of shark utilized on the Pacific coast 

 are the shovel-nose shark, thresher shark, and the man-eater or white 

 shark. The shovel-nose shark was taken extensivel}^ along the coast 

 of Humboldt County, Cal., from 1858 to 1868, from 50 to 60 men 

 being employed at times in the fishery. It is harpooned in deep water 

 and taken by means of hand lines in shallow water. This species 

 measures from 6 to 10 feet in length, and the liver of each individual 

 yields 3 to 7 gallons of oil. 



There are several species of skates, rays, etc., occurring on the 

 United States coasts which are utilized to some extent for oil-produc- 

 tion. Principal among these are the common skate {Raja erhiacea), 

 the prickly skate {E. eglanteria), the smooth or barn-door skate {R. 

 Icevis), the sting ray {Dasyatis centrura), the cow-nose ray {Rhino}}- 

 tera honasus), etc. Many thousands of these are captured by the men- 

 haden fishermen and utilized at the factories for conversion into Oil 

 and guano. Oil from the liver of the t(n-pedo or cramp-fish (Tls^ro- 

 narceoccidentalis), a large species, which at times attains a weight of 

 200 pounds, is said to be valued by the fishermen in the treatment of 

 cramp and rlioumatism. 



