TWENTY-EIGHTH BIENNIAL REPORT. 65 



the final stages, lias Jiot been completed for publication, and it is not, 

 at present writing, known how soon the writer can resume work upon it. 

 The material has collected faster than analysis can be made by the much- 

 interrupted labors of a single investigator, the more so as at times he 

 has lacked assistance of any kind. It is possible, however, to give a 

 resume of the results of the M'ork, which are of very considerable 

 interest, especially when compared to those of the sardine. 



In common with all investigations carried on by the Fish and TJame 

 Commission, the primary purpose of the work is to watch carefully for 

 evidences of depletion from overfishing. Of this there have to date 

 been found no good evidences in the albacore fishery, despite the decline 

 in catch. In view of this, the writer is not ready to recommend restric- 

 tive legislation which might aggravate a scarcity very probably due 

 to the habits of the fish. 



The great changes visible in the albacore catch and the distribution of 

 the fishing grounds cannot well be assigned to overfishing on the basis 

 of our present knowledge. The abrupt cessation in 1923 of the fishing 

 in the more northerly of the frequented grounds is not at all character- 

 istic of overfishing, if tlie history of other fisheries can be taken as any 

 criterion. Nor is it consistent therewith that the fishing near San Diego 

 should be unusually successful at the same time. Furthermore, the 

 decline to the north has been a failure to take fish from what schools 

 were present, whereas were overfishing and depletion the cause there 

 should be every reason to expect occasional good catches from small 

 schools. Unless these phenomena, upon investigation and analysis by 

 means of our statistical records, prove to have other meanings than 

 they apparently have, there is need for caution in coming to a conclu- 

 sion. 



Overfishing may nevertheless be taking place, despite this great vari- 

 ability. Developments in fishery science have served to indicate how 

 complex the factors may be which govern the abundance of fish, and 

 have rendered it questionable whether overfishing can always be dis- 

 tinguished from great natural fluctuations. It would therefore })e 

 advisable to conserve the species in so far as possible until our knowledge 

 of basic principles of fishery science can be more clearly applied. 



On the one hand, our work has indicated to us that the variability 

 in the runs of albacore, just as in the runs of sardines, must delay 

 recognition of overfishing and must throw increased emphasis upon the 

 necessity for correct and thorough statistics of the catch. Our "pink 

 ticket" system must become the foundation stone for oiir biological 

 analysis. 



But, on the other hand, the possibility of detecting overfishing is 

 heightened by the relative lack of variability in the numerical strength 

 of incoming age classes, since some clue may very probably be obtained 

 to the length of life. Analysis is proceeding along this line. The task 

 is a considerable one, but providing there is a lessening in the propor- 

 tion of mature taken, accompanying a decline in the catch, as shown by 

 our "pink tickets," it will be safe to attempt restriction of the fishery, 

 we believe. 



If this uniformity of incoming year classes continues in evidence 

 despite closer analysis and the records of succeeding years, there will 

 l)e no opportunity to foretell the catch by those methods so readily 

 applied in the case of the sardine, becau.se of the dominance of certain 

 age groups and the suppression of others in that species. 



5—34744 



