16 U. S. BUREAU OF FISHERIES 



mollusks themselves, their life histories and ecological relationships; 

 second, the stud}' of the plankton on which, either directly or indi- 

 rectly, they depend for their food; and third, the study of those 

 physical and chemical factors that determine the abundance of 

 planktonic forms. In the belief that the first of these has the most 

 immediate application in the solution of fishery problems, special 

 emphasis is being placed on life-history studies. Plankton and 

 oceanographic studies are being carried on, and their fundamental 

 character and importance are such that it is hoped that more ade- 

 quate provision may be made for them in the near future. 



It is felt that the results obtained in many of the researches 

 undertaken have already proved to be of such practical value that 

 the importance of the work of the division should be recognized by 

 increased appropriations. The investigations of the salmon of 

 Alaska, for instance, have made possible the control of this fishery 

 in a most scientific manner. The regulations now in force could not 

 have been outlined without the knoAvledge of the biology of the fish 

 which has come through intensive study of their life history and 

 migrations. Likewise, the regulations placed on the rapidly devel- 

 oping clam industry in Alaska were based upon the results of bio- 

 logical investigations. The mussel resources of the Mississippi 

 Valley, upon the maintenance of which the important pearl-button 

 industry depends, are being maintained by methods developed 

 through researches conducted by this division, and the improvement 

 of fish-cultural methods is founded largely on the results of various 

 scientific investigations. The value of such investigations as are 

 being made is receiving more recognition than ever before, and it 

 becomes increasingly difficult, with the present appropriations, to 

 meet the demands made on the division. 



The recent passage of the reclassification bill has greatly im- 

 proved the status of the employees and will make the service more 

 attractive to competent workers. However, the service of the divi- 

 sion does not depend entirely on having satisfactory salaries for the 

 men engaged in research. Adequate funds for equipment, travel, 

 etc., are required for carrying on the various investigations, and 

 the results of the efforts of the division will doubtless be in propor- 

 tion to the financial support given. Needed investigations are con- 

 stantly being postponed for lack of funds, and this delay is certain 

 to prove costly in the long run. Delay in the investigation of the 

 causes of depletion in a declining fishery may result in commercial 

 extinction, entailing an economic loss immeasurably greater than 

 the cost of investigation, and when such delayed investigations are 

 taken up they are almost certain to cost more than if performed at 

 the proper time. Furthermore, the chances for a successful solution 

 of the problem are less, since normal conditions are more and more 

 obscured as the fishery becomes more and more depleted. Efficiency 

 in the conservation and care of our fisheries demands additional 

 investigations, and it is hoped that more adequate support will be 

 given. 



The following pages contain an outline of the work conducted by 

 the division in its various investigations during the fiscal year ended 

 June 30, 1924: 



