BULLETIN OF THE UNITED STATES FISH COMMISSION. 207 
51.— TISE P I SC I € IT E T U BAL ESTABLISHMENT AT GEEM1Z (AIN), 
FRANCE.* 
By C. KAVEKET“WATTEL. 
About four years ago I had the honor to call the attention of the 
National Acclimatization Society to a piscicultural establishment which 
had been founded in the Department of Ain, at Gremaz, in the town- 
ship of Thoiry, for raising trout as an industry. I pointed out the spe- 
cial interest which, in my opinion, this establishment seemed to pos- 
sess, as its founders, Messrs. Lugrin and du Roveray, have succeeded 
in solving a problem of considerable importance from an industrial 
point of view, viz, to furnish the young fish with food solely composed 
of living prey proportioned to its size. 
It was exceedingly important to find some natural food for the young 
fish, and since Messrs. Lugrin and du Roveray have demonstrated the 
great usefulness of the Daphnice in this respect, several pisciculturists 
have looked for some practical means of providing a sufficient quan- 
tity of these small crustaceans. Attempts to multiply them rapidly in 
ditches filled with slightly muddy water succeeded ; but this method 
presents serious inconveniences. According to Mr. Ohabot-Karlen, the 
Daphnm gathered in these ditches are extremely tender; the least agi- 
tation kills vast quantities; the greatest precautions are therefore re* 
quired to gather them; and, moreover, these small crustaceans impreg- 
nated with muddy water must be carefully washed in clear water, in 
order not to become actual poison for the young fish. 
The method employed in the Gremaz establishment is by far prefer- 
able. As I have stated in my previous report (“ Bulletin de la Society 
d’Acclimatation” November, 1882), the Daphnice are raised in the very 
basins which are destined tor the fish. When a basin has been suffi- 
ciently prepared for the development of these small crustaceans, they 
are allowed about a month’s time to increase; then the fish are put in 
the basin, where they at once find abundant and substantial food. 
Whilst this stock of food is being consumed, other provision is made. 
A neighboring basin is prepared like the first; i. e., it is abundantly 
stocked with Daphnia. After another month has passed, the fish — 
which by -that time have consumed nearly all the food in the first 
basin — are put in the second, where they again find ample food. A 
month later they are again put in the first basin, which meanwhile has 
again become stocked with Daphnia , and so on. This method is ex- 
tremely simple and convenient. Messrs. Lugrin and du Roveray, how- 
ever, do not confine their efforts to raising Daphnia , but they likewise 
*Nouveaux renseignements sur Vetablissement de pisciculture de Gremaz (Ain). From 
Bulletin mensuel de la Society nationale d’ Acclimatation de France, fourth series, Vol. 
IV, No. 5, May, 1887. Translated from the French by Herman Jacobson. 
