PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1921. 59 
fertile, while the rate of fertility of the other lot was only 67. 
This and further experiments along the same lines gave these results: 
\McMahon| Hearell 
MeMahon| Hearell Fertile Fertile 
Pond. water. | water. eggs. Pond. water. | water. eggs. 
Per cent. | Per cent.| Per cent. Per cent. | Per cent | Per cent. 
OE be ee ee 00 0 BONING: Bisco iJoce ee tee 5 5 77 
1S ee Ge Saree 7 30 SOON Osh 5 5 uta rt rchine ot 30 70 67 
| 
It is unfortunate that more complete data on these experiments 
are not available, and perhaps the data at hand can not be accepted 
as conclusive. Nevertheless, the evidence seemed sufliciently strong 
to warrant the construction of two new ponds supplied entirely with 
the McMahon water and the alteration of present lines to admit of 
a further elimination of the Hearell water from the stock ponds. 
During the coming year the brood stock of rainbow trout will be held 
exclusively in ponds supplied with the McMahon water. The nature 
of the apparent ill effects of the water from Hearell Spring on the 
adult fish has never been ascertained, but an ovarian affection ap- 
pears to prevail among the fish that have been retained in that water 
for any considerable period. 
Another item of possible interest in trout culture at the Neosho 
station was the occurrence of a disease among the fingerling trout, 
both at the main station and at the Roaring River substation, re- 
sulting in some loss. The trouble first appeared as a discoloration 
of the gills from cream to brown in color, sometimes one and some- 
times both gills being affected. This was followed by an apparent 
disintegration of the tissues and finally by a peculiar sloughing off of 
the gill. The trouble manifested itself only in the newly constructed 
ponds or in ponds supplied with water from recently constructed 
reservoirs. On being removed to surroundings entirely remote from 
new concrete work the fish recovered rapidly, even in advanced cases 
where the gill seemed to have been destroyed. After being treated 
with a 1 to 1,000 solution of copper sulphate these affected ponds were 
allowed to remain idle for several months, and no trouble in con- 
nection with their use has since developed. 
The output of pond fishes also shows an improvement over the 
recent past, the aggregate having been exceeded only in two previous 
seasons. Further improvement in this line of effort involves some 
interesting problems. The ovarian trouble of the rainbow trout may 
be present among the pond fishes held in water from Hearell Spring, 
and investigations looking toward the solution of this phase of the 
subject are already under way. The station ponds devoted to the 
production of the warm-water species are well supplied with natural 
food for their young, and were fingerling fish produced to the extent 
of the natural food available the station’s output would be materially 
increased. The warm-water species propagated are largemouth and 
smallmouth black basses, rock bass, sunfish, crappie, and yellow 
perch. Artificial nests were tried in connection with the spawning 
of the largemouth black bass, with results that led the superintendent 
to recommend their general use. The output of the station by species 
is indicated in the tabular statement showing the production of fish 
by stations on page 12, 
