264 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



of these fish we shall eventually make Lake Como the Lake of Con- 

 stance of Italy. 



As regards the cultivation of Rhine salmon {Salmo salar), 100,000 

 eggs received from Mr. Carl Schuster, of Freiburg, Germany, were 

 placed in hatching boxes of the Green system on January 14, and after 

 they had been hatched the young fish were set at liberty on February 

 9 in the river Ticino. The day we placed the eggs in the boxes the 

 water of the river was somewhat turbid, but soon became fresh and 

 limpid again, having a temperature of 6° C. [about 43° F.], thus pre- 

 senting the necessary conditions for the young fish, although the yelk 

 sacs were not yet entirely absorbed. There was an alarming mortality, 

 due to the sediment which formed at the bottom of the boxes, although 

 this bottom was composed of a metallic net-work, and was separated 

 from the bottom of the river by a considerable amount of flowing 

 water, the Ticino having a rapid current. It must be said, however, 

 that the boxes of the Green system, which hitherto had been used only 

 for the cultivation of the shad {Alosa prwstahilis) in America, and which 

 I desire to see employed on a large scale in our lakes, have proved 

 themselves well adapted even to eggs which, like those of the salmon, 

 take a longer time to hatch. Another hatching experiment was made 

 with eggs of the grayling ( Thymallus vulgaris), which were placed in the 

 upper Oglio. Eighty thousand eggs were received from Mr. Schuster 

 (50,000 of them being in very poor condition), from which number we 

 succeeded in hatching about 15,000 beautiful and healthy young fish, 

 which, on May 27, 1885, were placed in the river not far from Darfo. 



It was not thought advisable to hatch the 100,000 embryonated aggfi of 

 the Salmofario and of the Sahno salvelinus, but those eggs which were 

 very near being hatched were placed directly in lakes and rivers. Many 

 fish-culturists, like Haack, Schuster, and Benecke, are opposed to this 

 metiiod ; but when there are difficulties in the way of hatching, as was 

 the case here, it seemed the best way of restocking the waters. The 

 chief objection seems to be that natural causes will destroy the o'^gs, 

 more especially that they will become a prey to their voracious enemies, 

 such as the Lota vulgaris, the Leuciscus ccphalus, and the Chondrostoma 

 soetta. But these fish do not approach the shores of the lakes in win- 

 ter, when the eggs of trout and similar fish are placed in the water. In 

 jdacing embryonated eggs in the water, everything will depend on the 

 selection of a suitable i)lace, and on having careful regard to the physi- 

 cal and iMological conditions of the water. Care should also be taken 

 not to crowd the eggs into too limited a space, but to scatter tliem 

 somewhat. Even if only ten out of every thousand reach tlie state of 

 maturity, there will be that many reproducers of fish in the public 

 waters. 



Hardly had the 100,000 trout eggs been received from the establish- 

 ment of Torbole, on January 8, 1885, when one-half was planted at the 

 mouths of the rivers Plesna and Rivalaccio, near Pella j while the other 



