There are more definite data concerning crustacean food for 

 young fish beyond the entomostracan-feeding stage. Some 20 or 

 30 years ago, fish-cultural establishments in Europe utilized the 

 larger crustaceans, particularly the amphipods, commonly called 

 shrimp, to a considerable extent. Over 30 years ago Consul Frank 

 H. Mason^ described in some detail the manner of raising shrimp 

 for trout food at Lugrin's establishment at Gremaz, France, a famous 

 fish farm of those days. He stated that the ponds were about 120 feet 

 long by 12 feet wide, with a depth of 5 feet. Each pond would pro- 

 duce 650 to 900 pounds of shrimp in a month. These supplied 

 20,000 yearlings and 3,000 two-year-old fish with 20 to 25 pounds of 

 shrimp a day, or about 600 to 800 pounds a month. It was necessary 

 to have two ponds for each kind of fish, owing to the fact that 

 instead of transferring the shrimp to the fish ponds it was the custom 

 to drive the fish from one pond to another each month, so that while 

 they were eating the stock of shrimp in one pond the other was being 

 replenished. Two shrimp ponds would probably have been necessary 

 for each, even if the feeding had been by transfer of the crustacaeans 

 instead of the fish. 



If the number of fish is increased, the capacity of the shrimp 

 ponds would need to be correspondingly increased. Four ponds of 

 the above dimensions would aggregate about one-tenth of an acre. 

 Ponds of the necessary capacity for raising amphipods or shrimp for 

 a given number of fish would not appear prohibitive at most large 

 hatcheries. 



It is stated that the fish fed upon nothing but the products of the 

 shrimp ponds, upon which they thrived. To be sure the ponds con- 

 tained some other organisms, but the shrimp were in greatest abun- 

 dance. The fish referred to v/ere the European trout, in this country 

 commonly called brown trout. The question arises as to how the 

 quantity of crustacean food in this European operation compares 

 with that supplied to the common brook trout and the rainbow trout 

 at our hatcheries. 



At the Spearfish (S. D.) station, in the month of July, 1,000 

 brook trout brood fish averaging one pound in weight were fed on 

 a mixture consisting of 93 pounds of mush and 186 pounds of liver, 

 a total of 279 pounds. At Gremaz it required 600 to 800 pounds of 

 shrimp to feed about 1,500 pounds of fish comprising 3,000 indi- 

 viduals averaging one-half pound each. At Spearfish it would have 

 required 418.5 pounds of the combination food mentioned to feed 



1 Bull. U. S. Fish Commission, Vol. VII, 1887 (1889), pp. 203-206; and Trans. Amer. 

 Fisheries Soc, 1892, pp. 58-77, including discussion. 



