60 PISH AND GAME COMMISSION. 



be of great economic importance to the trade, because upon tbem 

 depends the success or failure of the fishing, and their assignment to 

 natural causes must be an insurance against rash and ill-advised 

 restrictive legislation. 



In these first reports upon the sardine it has been sought to accurately 

 indicate the actual changes which occur, regardless of traditional beliefs 

 regarding the species, and it has been sought to emphasize the fact that 

 the present work is part of a permanent program; that not only does 

 conservation of marine fishes require the eternal vigilance of a well- 

 handled statistical system, but that the understanding or foretelling of 

 natural changes requires continuous study. 



SCOPE OF THE REPORTS. 



It must be understood before the findings of the work are presented, 

 that a rigid adherence to a practical end was insisted upon from each 

 of the assistants. This, the understanding of the commercial catch, 

 necessitated first of all the accurate portrayal of that catch as it 

 actually existed. It was realized that a theory is of no use if the thing 

 it is supposed to explain does not exist, and that a secure basis of fact 

 must exist for any theory. Therefore, instead of presupposing a com- 

 plex of migrations and miscellaneous phenomena to which almost any- 

 thing could be assigned, and which fishermen's theories and observa- 

 tions should be regarded as proving, it was sought to impartially and 

 rigidly record the facts of the run of fish. Our reports are, therefore, 

 not attempts to explain phenomena which we merely suppose to exist, 

 but they are records of what phenomena actually do appear. 



The first and most natural step in such a rigidly scientific procedure, 

 was to find out how extensive our records must be to show the tenden- 

 cies we desired to analj'ze. The only feasible way to accomplish this 

 was to make sure that we had determined these tendencies as nearly as 

 might be, by securing an excess of records. Then, by breaking these 

 into independent series and comparing them, the degree of divergence 

 one from the other would indicate to what extent the catch was dis- 

 torted by reducing the extent of the record. Were two entirely inde- 

 pendent series of samples of the catch similar in what they show^ed, 

 then the inference is fair that what they indicated must he the truth. 

 This is tlie phase of the problem dealt with by Mr. Sette. 



Mr. Sette has shown that to obtain a picture of the year's catch which 

 is sufficiently correct to use, it is necessary to sample the commercial 

 catch twice a week. He has shown that systems of samjiling used by 

 other investigators upon the herring wouUl be entirely inad(M(uate in 

 the case of the sardine. In coming to this conclusion he was not aided 

 1>\- m\y analysis of their own methods made by these investigators and 

 we l)elieve that our anlaysis of what is necessary is one of the first to be 

 made for any great fishery. 



Upon this basis of what we knew was necessary, the remaining reports 

 ;ii-c made l)y Mi". Elmer Higgins, Mr. W. L. Scofield and Mr. W. F. 

 Tliompson. ^riicy constitute a presentation of the coiumcrcial catch as 

 a rigid system of sam])]ing shows it. 



Mr. Iliggins and Mr. Scofield show that tliere is a well-marked change 

 ill tlic catch from year jo yeai' and that the al)iindantl\' n'|)i-esented 

 sizes shift in a consistent way from year to year. This change is due 



