64 . U. S. BUREAU OF FISHERIES. 
mouth black bass and 9,904 sunfish, all of the fingerling 23 size. 
Thirty adult crappie, obtained during the season for use as brood 
fish, failed to reproduce, the fluctuating air and water temperatures 
during the spawning season having a decidedly unfavorable in- 
fluence on these fish, as it also did on the bass. No recent changes 
have occurred in the method of conducting the work at this point. 
LOUISVILLE (KY.) STATION. 
[CHARLES W. BuRNHAM, Superintendent. ] 
The fiscal year 1921 marks the most successful season in the his- 
tory of the station in the production of fish. The output aggre- 
gated 1,020,450 fry and fingerlings, divided, by species, as follows: 
Largemouth black bass, 33,100; rock bass, 4,500; smallmouth black 
bass, 156,700; sunfish, 76,150; and yellow perch, 750,000. These 
fish were distributed to applicants in Kentucky, Indiana, and Ohio, 
and liberal plants of sunfish were made in local waters. 
The brood stock of smallmouth black bass was increased during 
the year by the purchase of 277 adults from Lake Erie fishermen. 
Of this number 52 died shortly after being received. The remain- 
der were placed in a spawning pond, but failed entirely to spawn. 
It is difficult to assign a reason for this, as the fish appeared to be in 
a healthy condition throughout. A number of those that died from 
the effects of transportation were examined and found to be carry- 
ing eggs, and the 125 older fish at the station produced very excellent 
results under similar conditions. 
It is perhaps worthy of mention here that of the 200 adult small- 
mouth black bass sent to the Mammoth Spring (Ark.) station from 
Lake Erie none survived the winter. In connection with the propa- 
gation of the basses, it is interesting to note that the young small- 
mouth black bass grow much more rapidly than the young of the 
largemouth black species. 
_ Yellow-perch propagation at Louisville was successful this sea- 
son, the 750,000 fry distributed being the progeny of 300 brood fish. 
It may be possible to considerably extend this branch of the work 
by increasing the number of breeders carried in the ponds. 
MAMMOTH SPRING (ARK.) STATION. 
[WILLIAM 8. VINCENT, Superintendent. ] 
A considerable amount of work looking to the improvement of 
the pond system was accomplished at this station during the year. 
Such work in the main has consisted in the installation of concrete 
“kettles” and outlets in many of the ponds, comprising what is 
believed to be an innovation in pond construction. (See Fig. 3, opp. 
p- 68.) Improvements were also made in the drainage system. Four 
small rearing ponds were converted into one large one, and work 
was done for the improvement and increased fertility of the bottoms 
of the ponds. 
In an effort to build up the brood stock a number of adult fish of 
the various species propagated were obtained from local waters dur- 
ing the late summer and early fall. In October 200 adult small- 
mouth black bass were transferred from Lake Erie. Most of these 
were unable to survive the winter, and all had perished prior to the 
