PROGRESS IN BIOLOGICAL INQUIRIES, 1935 383 



circumscribed during the past severtd years as a result of curtailed 

 funds. Nevertheless, much progress has been made during 1935. 



As our knowledge of the vast, continually changing network of 

 factors influencing aquatic life increases from year to year, it be- 

 comes ever more possible to conserve the fisheries l)y numagement 

 rather than by restriction. Thus, for the fresh ^Aater species through- 

 out the country, much progress has been attained m making the in- 

 land waterways l)iologically more habitable and productive. This is- 

 being accomplished in two "ways: first, by discovering sources of pol- 

 lution and encouraging their elimination, usually with the friendly 

 cooperation from owners of factories and mills bordering the water- 

 ways; second, by developing methods of improving the natural en- 

 vironment in streams so as to make them more productive of fish 



life. . , , 



The populations of fresh-water fishes have continued to be main- 

 tained and distributed by stocking from hatcheries. Current re- 

 search in this field is devoted mostly to improving the breed of stock 

 so as to obtain the highest fecundity and fertility ; also to develop- 

 ing the most efficient feedstuft's so as to get the most fish per pound 

 of feed. There is still an enormous amount of research to be done 

 in the field of aquiculture, however, particularly with reference to 

 the relation between eiiviromiiental influences and population growth 

 and decline. 



As for the commercial fisheries, the most important work in this 

 field has been the development of our knowledge concerning the 

 causes of the great fluctuations in abundance which so deeply affect 

 the fishing industry. Tb.e complicated interrelations between these 

 fluctuations, the fishing intensity, the population abundance, and the 

 birth and mortality rates continue to be the subject of intensive 

 studies. 



Another important phase of activity in the Division of Scientific 

 Inquiry is concerned with the shellfish industry, particularly with 

 respect to oysters. The most productive work in this field during 

 1935 has been the development of effective methods for curbing the 

 destructive enemies of the oyster, namely, the starfish and drills. As 

 was pointed out in the 1934 report, however, there still remains a vast 

 amount of work to be done in the field of oyster culture and oyster 

 farming. 



COOPERATION 



An effective program of conservation thi'ough management is im- 

 possible without the wholehearted cooperation of all the people 

 directly or indirectly affected by such a program. It is gratifying, 

 therefore, that States, other Federal departments, and private indus- 

 try are working with the Bureau of Fisheries more than ever in carry- 

 ing on scientific fishery investigations. But it must be pointed out 

 tliat even this much cooperation is not enough. It is true that the 

 provision of biologists, of laboratory facilities, of boats, of test 

 streams, of moral support goes a long way toward achieving the 

 scientific knowledge that is needed for intelligent fishery manage- 

 ment; but this knowledge will be of little use until neighboring States 

 cooperate w4th each other in formulating, passing, and enforcing 

 effective and consistent conservation legislation. That is work of the 

 States that remains to be done in order to make these scientific inves- 

 tigations useful. 



