IV REPORT OF THE COMMISSIOXEB OF FISHERIES 



indeed, of mere maintenance become more difficult and requii-e addi- 

 tional investigations it' the}' are to be adequately and scientitically 

 met. 



If economic losses due to depletion of the fisheries are to be pre- 

 vented — and this, in the last analysis, is the primary function of the 

 Bureau of Fisheries — it is essential that information be secured 

 which will provide a measure of the condition of a fishery, particu- 

 larly Avith respect to its depletion. It is important that this infor- 

 mation be secured before depletion has oone far. Ii it is delayed 

 until the diminution in the supi3ly has become apparent to the casual 

 observer, it may be too late to prevent serious depletion or even 

 commercial extinction. The statistics of the fisheries are not alone 

 adequate for this purpose, important though they be, but these must 

 be interpreted in the light of a knowledge of the life history of the 

 various species on which the fisheries depend — particularly such 

 matters as the rate of growth, age of the breeding fish and of those 

 usually taken for commercial purposes, migrations, etc. Such data 

 as these, and many other, are needed even more urgently if deple- 

 tion, once discovered, is to be remedied. The scientific investigation 

 of the fisheries provides data that are essential to the proper conser- 

 vation of these resources. 



A knowledge of the condition of a fishery may be applied not only 

 to the purposes of preventing and remedying depletion, however, 

 but also to directing the expansion of a fishery. Not all of our fish- 

 ery resources show depletion or appear to be in danger of overex- 

 ploitation. With adequate data it would be possible to direct fishing 

 effort from a depleted resource to one capable of withstanding addi- 

 tional exploitation. The true conservation of our fishery resources 

 is conceived to include not the mere saving of these resources, but 

 their utilization to the fullest possible extent compatible with their 

 peri)etuation. The conservation of the fisheries should partake more 

 of the nature of husbandry than of mere saving, and the husbandry 

 of fisheries is no less an art than the husbandry of the plants and 

 animals reared on our farms. The care of the fisheries has not been 

 developed to the stage of perfection reached in the care of the im- 

 portant agricultural products, but advances have been made and are 

 being made in spite of the fact that, in many ways, the problems are 

 more difficult. The factors involved are moiv complex and obscure, 

 and most fishes are for most of their lives beyond the control or even 

 the observation of man. Such comparatively simple and essential 

 items as their rate of growth and age can frequently be obtained 

 only by indirect methods, which must l)e applied in the light of ac- 

 curate biological information and which often require the use of 

 <'ai-eful methods and long-continued and often arduous and monoto- 

 nous work on the part of the investigators. 



New methods for investigating fishery problems have V)een de- 

 A'eloped in recent years. In this newer line of fishery researcli em- 

 phasis is placed not so nuich on a study of tlie individual fish as upon 

 the study of the species as a imit, the factors that affect the sur- 

 vival of the race, and the general relationship of the species as a 

 ■whole to the physico-chemical and biological elements in its en- 

 vironment. The problems in this new line of fishery research are so 

 complex that they may demand years for solution and require in- 

 vestigatoi^ of unusual training, ability, and perseverance. In this 



