PROGKESS IN BIOLOGICAL INQUIEIES, 1921. 



5 



knowledge as we have of the life history of the crab — in short, upon 

 the results of scientific work previously done. Emphasis must be 

 put upon the adverb of time. The significant thing is that the work 

 must in great part, at least, have been already done ; for knowledge 

 can not be secured immediately ; one can not produce the life history 

 of an aquatic animal upon demand ; it is the result of painstaking 

 study through a period of time Avhich can not be fixed in advance, 

 and by the application of methods which can not be definitely plotted 

 beforehand. 



It is work of this kind which must be done, and continuously done, 

 so that gradually and steadily we learn more and more about our 

 fishery animals, if we are to be ready at all times to meet the chang- 

 ing problems of regulation and exploitation as they arise. 



The scientific knowledge which is the basis of the future welfare 

 of the fisheries requires not only time and application, but also 

 skill and special training. Of greatest importance are the services 

 of men who have not only natural qualifications and the preliminary 

 training which institutions of learning can give, but also such special 

 experience, interest, and devotion as can be gained only as the result 

 of prolonged application to fisheries studies. Something may be done 

 with inexperienced and changing agents, but the most successful 

 and economical work will be done with a trained and continuing 

 force. 



In the following report will be found not an account of what might 

 have been done, or what ought to have been done — but rather a state- 

 ment of the progress which has been attained under the difficult con- 

 ditions by which the scientific work of the Bureau has been circum- 

 scribed. It may be added that the Bureau again closes the year vv^ith 

 a less effective force than it had at the beginning. Two members of 

 the already depleted staff have resigned to accept better paying posi- 

 tions elsewhere, and two (including one rendering largely volunteer 

 service) have died and not been replaced. Special acknowledgments 

 are due to those whose interest and loyalty have held them in the 

 public service. 



In reviewing the subject of investigation it must be understood 

 that while the Bureau has a definite policy of restricting expendi- 

 tures to investigations of the most direct practical bearing, it is not 

 entirely untrammeled in the selection of subjects of investigation. 

 The qualifications of the personnel available necessarily determine in 

 part the character of problems which can be profitably attacked. 



STUDIES OF FISHES. 

 THE PACIFIC SALMON. 



When consideration is given to the magnitude of the industries 

 based upon the salmons and their near relatives, to the unrivaled 

 rank which some of these fishes hold in the realms of sport and 

 recreation, to the comparative ease with which the more important 

 species may be brought to virtual extermination, and to the fact 

 that all important species are the subject of artificial propagation, 

 it is apparent that no group of fishes demands a greater share of 

 attention in the way of scientific study. 



