COMMISSIONERS OF INLAND FISHERIES. 81 



CHAPTER VIII. 



THE PROPAGATION OF MARINE FISHES. 



The possibility of using our lobster-rearing apparatus for the 

 hatching and rearing of various food fishes has been spoken of in 

 previous reports. In the spring of 1910, this was actually accom- 

 plished, and by a specially devised adaptation and arrangement of 

 the "filter windows" it became possible to retain such minute forms 

 as fish larvae, clam spawn, etc., and at the the same time have ade- 

 quate circulation of water. 



THE WINTER FLOUNDER. 



(Pseudopleuranectes americanus.) 



This past spring over twenty-five million of these fish were hatched, 

 and liberated in Mill Cove, Wickford. An attempt was made to 

 develop a simple and inexpensive method of hatching the eggs of this 

 extremely prolific fish. A certain amount of success was attained in 

 this direction, and your Commission intends, this coming spring 

 (1911), to carry out the ideas on a more extensive scale. 



REARING THROUGH THE TRANSITION PERIOD. 



On account of their extremely small diameter immediately after 

 hatching, and especially after the yolk-sac has been absorbed, it was 

 practically impossible to retain these fish until the " filter windows, " 

 described above, were devised. However, when a method of retain- 

 ing them had been hit upon, the fish themselves were found to be 

 quite hardy and to require little care. In one of our rearing cars 

 several thousand were reared successfully through this period. The 

 following facts in regard to the changes in structure and habits were 

 corroborated in our work this past year and are given here, because 



