REPORT OF THE COMMISSIONER OP FISHERIES XXXIII 



has Ionised the attention of increasing numbers of people upon the 

 problem of developing and maintaining a permanent supply of fish. 

 This is the immediate problem, with its many ramifications, upon 

 which the scientific investigations of the bureau are focused. 



Fishery science differs from the older marine biology not so 

 much in method or even in subject matter as it doe.; in point of 

 view. Its object is the discovery of the limiting factors that regulate 

 the abundance of the various species of fish of commercial value and 

 the application of this knowledge to the protection and wise utiliza- 

 tion of these species. In this sense it is an applied science and may 

 be likened to the science of animal husbandry. Indeed, the hus- 

 bandry of fishes on a thoroughly practical and scientific basis is 

 a goal toward which we may strive with hopes of not too distant 

 attainment. But fishery science is ;.o unorganized that the causes 

 that control the fluctuating abundance of fish are little understood 

 and require the study of a great range of fundamental and often 

 elementary facts in aquatic biology. Because of this great diversity 

 of subject matter the principle of cooperative research that has been 

 found so effective in other lines has been applied to the major 

 projects of the division's work. As an example of cooperative or 

 group research in fishery science the investigation of the cod fishery 

 in the western North Atlantic may be cited. This investigation is 

 not only being carried on by the three governments most directly 

 concerned in the prosperity of this fishery, but each investigator is 

 attacking the problem from a different angle. 



The present state of the cod fishery and the distribution of fish 

 (in point of abundance) on the fishing banks and inshore areas is 

 being determined by a statistical analysis of the records of yield. 

 The factors that affect this varying abundance are being sought by 

 studying the embryology and early life history of the fish, its 

 period of spawning and rate of development, the migration from 

 bank to bank, the localization of the distinct races of the species, 

 and such physical factors as temperature, salinity, currents, etc., 

 that affect the fish throughout its entire life. A knowledge of its 

 food habits also is being attained, together with the variations 

 in character and abundance of the microscopic organisms upon which 

 it depends for its food in the early stages of its growth. Thus 

 statisticians, biologists, biochemists, planktonologists, and oceanog- 

 raphers are cooperating to a degree scarcely attained heretofore, each 

 conducting investigations that individually may be considered 

 problems in pure science but which are so coordinated and centralized 

 that complete and useful understanding of the fishery and its 

 problems is rapidly being attained. 



The investigations of the fisheries of the North Atlantic are being 

 fostered, and to a large degree directed, <by the North American 

 Committee on Fishery Investigations, composed of delegates from 

 the countries having the largest fishing interests in this region, 

 namely, Canada, Newfoundland, the United States, and France. A 

 meeting was held in Montreal in November, 1925, at which Dr. II. B. 

 Bigelow and O. E. Sette represented the United States. In order 

 to evaluate the total productivity of the North Atlantic fishing banks, 

 plans were made to secure mutual exchange of fishery statistics be- 

 tween all of the countries participating, and in the furtherance of 



