50 U. S. BUREAU OF FISHERIES 
mercial fishery probably refiects fluctuations in abundance more or 
less imperfectly, depending on whether fishing conditions are favor- 
able or unfavorable. For these reasons the recognition of an irre- 
versible decline in abundance is not easy, but requires evidence on 
many aspects of the fish and the fishery. 
During the season of 1938-39 the exploitation of the fishery was 
modified by withdrawal, in midseason, of floating reduction plants 
from high-seas operation. This action was the result of economic 
difficulties during the early part of the season and of the previous 
year, and coinc sided with the passage, by referendum, of an amend- 
ment to the State Constitution giving the California State Fish and 
Game Commission authority to ‘prevent deliveries by California fish- 
ing boats to establishments outside of the jurisdiction of that State. 
The season’s catch was as follows: California, 574,676 tons; Oregon, 
17,018 tons; Washington, 26,483 tons; British Columbia, 52,049 tons; 
a grand total of 670.226 tons. Of this quantity, 44,000 tons were 
‘aught for floating reduction plants operating on the high seas off 
San Francisco. 
The total was more than 37.3 percent higher than that of the previ- 
ous season. This increase probably may be ascribed to a natural 
fluctuation in abundance brought about by the entrance into the fish- 
ery of unusually successful year-classes produced some years previ- 
ously; probably in 1934 to 1986. This probability is suggested by 
the higher percentage of young fish in the catch. It is difficult to 
determine, however, from present evidence, whether the increase is 
due altogether to these Incoming year-classes, or partly to a better 
availability than obtained the previous season. An apparent dearth 
of older fish also raises the question as to the possible existence of 
a fundamental decline obscured by the accession of so many young. 
The program of work discussed herein was carried out by a staff 
consisting ‘of O. E. Sette, who was in charge of the investigation, 
Dr. L. A. Walford, Kenneth Mosher, Ralph Silliman, Earle Palmer, 
and Robert Luckhardt. The broad scope of the investigation and its 
accomplishments were possible only because of the cooperation and 
assistance of several organizations and persons. Clerical and techni- 
cal assistance were furnished by W. P. A. Projects 7023-1 and 
10917; thus, 10,000 scales and a like number of otoliths were mounted, 
550 bottles of plankton were sorted, and extensive statistical processes 
were carried on which would not otherwise have been possible. The. 
extensive plankton research was made possible by the cooperation 
and collaboration of the Scripps Institution of Oceanography and its 
director, Dr. H. U. Sverdrup. Subsequent studies on hydrographic 
data carried on by Mr. Richard Tibby, of that institution, were made 
available immediately to the Bureau for its biological studies of the 
young pilchard. The California State Fisheries Laboratory, the 
Fish Commission of Oregon, the Department of Fisheries of Wash- 
ington, and the Fishery "Research Board of Canada all contributed 
records essential to various phases of the Bureau work of 1938-39. 
Stanford University contributed laboratories for the central office, and 
also provided facilities in Hopkins Marine Station for the Bureau 
field man stationed at Monterey. Members of the faculty of Stanford 
University, notably Drs. Frank W. Weymouth and Willis H. Rich, 
contributed advice on matters pertaining to the Bureau program. 
