REPORT OF COMMISSIONERS OF INLAND FISHERIES. 105 



First, to the problem of hatching and rearing to an optimum size for 

 liberation quantities of fishes of economic value for the direct pur- 

 pose of stocking the waters. The comparative ease of hatching eggs 

 of most fishes has resulted in the establishment of many prolific 

 hatcheries; on the other hand, the number of establishments capable 

 of rearing young fishes and the number of species so reared in con- 

 finement are few. A method of culture, therefore, which is capable 

 not only of hatching, but of rearing large numbers of fishes of widely 

 different species marks, we hope, a new step in fish culture. 



The second general problem is the ascertainment of the appearance, 

 habits, requirements, and rate of growth of economically important 

 fishes in their early stages of post-embryonic development. As 

 contrasted with the vast amount of investigation of the embryonic 

 stages of development, which has been facilitated by the abundance of 

 readily available material in the form of eggs of all stages, the data 

 relating to the post-embryonic development is almost entirely lacking. 

 Even the identification of the young of many food fishes abundant in 

 their spawning season is at present impossible. A method by which 

 eggs of widely different species may be hatched and reared and by 

 which the unidentified fry caught at large may be reared under obser- 

 vation, will be able, we hope, to furnish the necessary material for the 

 solution of this general problem. 



APPLICATION IN TRANSPORTATION OF LIVE FISHES. 



In our opinion the essential principle upon which this method of 

 fish culture is based will be found of value in solving the problem of 

 the transportation of live fishes and, moreover, the method and 

 even a portion of the apparatus can be modified and adapted so as to 

 carry this principle into effect. The principle is, briefly, to provide 

 at the start native "unmodified" water; to maintain a proper tem- 

 perature and density, and in some cases current; to secure the con- 

 tinuous "respiration" of the water, including the egress of waste gases 

 of the metabolism of contained fishes and often of bacteria as well as 



