42 FISH AND GAME COMMISSION 



all times, the present larger catch is a harvest of the surplus male crabs 

 which have reached maturity. 



SHARKS 



Sharks have always been considered a nuisance by both the sport 

 and commercial fishermen. These fish tear their nets, eat their bait, and 

 are believed to be predators of the important food fishes. Previous to 

 1937, an average of only 500,000 pounds a year of sharks had been 

 utilized in fresh fish markets, and most of the sharks taken in nets 

 and on lines had been knocked on the head and cast back into the sea. 

 During 1937, it was found that the liver oil of certain species of sharks, 

 notably soupfin, was high in the number of vitamin A units. Several 

 companies in California became interested in obtaining the sharks for 

 the liver oils, for use in fortifying the vitamin content of other 

 fish oils, such as that of sardines, utilized in poultry and animal feeding. 

 The demand for shark liver oil caused fishermen to turn from other 

 fishing activities to shark fishing. The catch, which was 914,000 pounds 

 in 1937, increased to 7,504,000 pounds in 1938, and to 9,157,000 pounds 

 in 1939. Prices started at $40 per ton to the fishermen in 1938 and 

 increased until $70 per ton is now paid for soupfin, the most desirable 

 species. It is reported that the price may be $80 or more per ton before 

 the 1940 season closes. 



Because the majority of the shark catch is now used in an extrac- 

 tion or reduction process, it became necessary for the Division of Fish 

 and Game to issue reduction permits to companies wishing to process 

 sharks for their liver oils. Shark carcasses, after the liver has been 

 removed, are used to some extent for fresh food, but 90 per cent are 

 made into meal. 



Some of the shark fishermen and reduction operators, as well as the 

 Division, are doubtful if the shark supply can withstand such heavy 

 exploitation. Some protection may be desirable after further investi- 

 gation. 



Report of the California State Fisheries Laboratory 



By W. L. ScoFiELD, Supervisor 



The goal sought in the management of the marine fisheries of the 

 State is full utilization consistent with sustained yield. This implies 

 maintaining a full breeding stock from which is harvested an annual 

 crop approximately equivalent to the replacements spawned from year 

 to year. The research program of the laboratory is designed to furnish 

 to the administrative officers the necessary information as to the state 

 of the snpi)ly. degree of utilization, effectiveness of present laws, and 

 the life histories and behavior of the various species, so that more 

 ef^cient regulations may be enacted if they are needed. 



A' moderately comprehensive knowledge of changes in abundance, 

 degree of utilization and life histoi-y of any one species requires, in 

 most cases, sevei-al years of study followed by continuous observation 

 so long as the fishery is in need of management. Without unlimited 

 jiersonnel and funds, such detailed studies nuist be confined to the most 

 important species only and the lesser marine resources must be observed 



