American Fisheries Society. 109 
sac. Further control experiments will be made in order to ob- 
tain more definite information on this subject. 
SUPERAERATED WATER. 
A suggestion comes from Fish Culturist G. W. N. Brown of 
the Erwin station that fry being carried in troughs supplied 
with superaerated water will thrive best if less than the normal 
supply flows through the trough. No control experiments have 
been made, but it is suggested that when opportunity is offered 
it would be a good idea to make control experiments along this 
line. He speaks of carrying from 30,000 to 50,000 trout fry 
from the period of hatching to four months old in troughs having 
a flow of water from three to seven gallons per minute. It was 
observed that when the flow of water was increased the death 
rate increased correspondingly. 
COPPER SULPHATE AS APPLIED AT A TROUT HATCHERY. 
At the White Sulphur Springs, West Virginia, station the 
water supply is from springs. For a distance of 200 feet from 
the intake the water is conducted underground in terra cotta 
pipes. It is then conveyed in an open ditch for about a 1,000 
feet. This ditch at the water surface is about seven feet wide, 
and from 2 to 3 feet deep. It is tapped at a number of places 
for supplying the different ponds. Spirogyro grown very rapid- 
ly in this open ditch, clogs the screens at the various intakes, 
and is thus very objectionable. It has been found that the ap- 
plication of copper sulphate in a mixture of about 1 part to 
4,000,000 applied about 8 hours each week, almost entirely eli- 
minates the algae, with no injurious effects upon the fish. After 
the copper sulphate has been applied for the stated period the 
fish eat but little food, and if applied 16 hours will entirely re- 
fuse it. The lack of appetite lasts but about 12 hours after the 
application has been discontinued. 
The flow of water through the ditch was only roughly meas- 
ured, hence the proportions given above may not be correct. 
The experiment was conducted under the direction of the pathol- 
ogist of the Bureau, M. C. Marsh. The copper solution was dis- 
solved in a barrel, and was applied at the head of the ditch by 
