Howeverp there are things to be desired in a commercial fishery 

 beyond merely a continuing yield of maximal members of fisho The stock 

 mijiS'c be S'off ioiently abundant to be economically fishable and the sizes 

 of fish in the catch should be economically desirable o 



At the present stage of research on the pilchard population, we 

 do not have any notion of the level at which maximixm replacement would 

 take places nor as to whether the abundance at that level would be an 

 economio one or whether the size composition would be commercially de= 

 sirableo We can, however^ be confident that the replacements the abund- 

 dance,, and the size composition will be affected by the fishing intensityi 

 and we can be sure also that we shall want the replacement to be equal 

 to the catch so that no continuous decrement will ensue o 



Therefore„ for the time being, the objective is "to determine at 

 various levels of fishing intensity the quantity and quality (sizes of 

 fish) in the average annual catch." Choice of the optimum intensity can 

 then be made among the consequences of the various fishing intensities 

 according to what is economically and socially desirable o That will 

 undoubtedly involve other than biological considerations o 



It should be noted particularly that it is not an objective to de- 

 termine whether abundance is decreasingo The population can be expected 

 to decrease long before maximal yield is reached. It is not along an 

 objective to determine whrther the average size of the fish is decreasing. 

 This probably will be the finding but is not of itself a sufficient in- 

 dicator of a desirable or undesirable situation. No mention is madi^ of 

 protection of s pawners or of spawning grounds, or of size limits, or of 

 closed seasons, or of wasteful practices in utilization, or of other topics 

 that often are the concern of conservationists. These items may or may 

 not be involved eventually. At this time, they are secondary to the de- 

 termination of what consequences attend different amounts of fishing and 

 cannot be intelligently considered until these are known. In fact,, the 

 method of conserving a commercial fishery involves social, economic, 

 and political considerations and lies in the field of political economy. 

 Biologists need only determine the consequences of certain actions and 

 make them known to the law-makers and administrators. 



Characteristics of Catch and Stock 



The objectives are stated in terms of v/hat will be caught at dif- 

 ferent levels of fishing intensity. With sufficient information, the 

 characteristics of the catch could be defined each season, and over a 

 long time, empirical curves could be made that would show the relationship 

 of intensity of fishing v/ith quantity and quality of catch. Indeed, 

 save for data on fishing intensity, ready collection of which was pre- 

 cluded by certain practices of the fishery, this job of biological ao-= 

 coxaating has been done by the California State Fisheries Laboratory over 

 a period of 23 years during which the fishing intensity has varied widely. 



