THIRTY-FIRST BIENNIAL REPORT 



129 



REPORT OF THE CALIFORNIA STATE FISHERIES 



LABORATORY 



By W. L. ScoFiELD, Acting Director 



As stated more fully in the twenty-ninth and thirtieth biennial 

 reports, the research program of the Bureau of Commercial Fisheries 

 concerns itself with determining tlie present state of the supply of our 

 more important commercial fisheries, the determining of the presence or 

 absence of over-utilization and the examination of such questions as 

 bear directly upon the effectiveness of present or proposed legislation 

 for the protection of the state 's fisheries resources. 



The biennium 1929-1930 has been a period of accomplishment and 

 the present report may well confine itself to summarizing the progress 

 already made. 



Fig. 48. California State Fishieries Laboratory, Terminal Island, California. 



Photo by D. PI. Fry, Jr. 



ANALYSIS OF BOAT CATCHES 



The outstanding accomplishment of the last two years has been the 

 perfecting and application of methods for analyzing the catches of 

 individual fishing boats. The dailv catch of a boat utilizing a certain 

 type of fishing gear is being used as a unit of fishing effort. Average 

 daily or monthly catches for a representative group of boats over a 

 period of years are compiled and analyzed so as to discount price 

 changes, altered fishing methods and such other economic factors as 

 affect the catch. As a result we have a fair picture of the changes 

 occurring in the actual abundance of our commercially important 

 fishes. 



9—81166 



