72 U. S. BUREAU OF FISHERIES. 



increase the aggregate for 1922 by 4,960,000, which includes 4,900,- 

 000 yellow perch and 60,000 pike perch distributed, and for 1921 by 

 500,058, representing 500,000 pike perch and 58 yellow perch dis- 

 tributed. 



ERWIN (TENN.) STATION. 

 [A. W. Keesecker, Superintendent.] 



During the year a number of improvements were made in the 

 water supply and drainage systems and in certain of the ponds. 

 Among the more important items accomplished were the installation 

 of a new water-supply line, replacing the line in use for many 

 years ; the construction of a retaining reservoir in the spring branch 

 from which water is now conducted to increase the flow in the stock 

 ponds; a retaining wall around the main spring, protecting it from 

 surface drainage; and certain changes and improvements to pond 

 outlets. 



Six species of fish came under artificial propagation at this station 

 during the year, namely, the rainbow trout, brook trout, large- 

 mouthed black bass, small-mouthed black bass, rock bass, and sun- 

 fish. In addition to those enumerated a small number of adult catfish 

 transferred from the Bulloch ville (Ga.) station were on hand but 

 were entirely nonproductive. 



The spawning period of the rainbow trout extended from October 

 27 to January 10, the brood stock of about 1,600 female fish pro- 

 ducing, in round numbers, 1,250,000 eggs. Of the number retained 

 at the station 89 per cent produced healthy fry. The brook trout 

 appearing in the distribution records were the result of eyed eggs 

 acquired by purchase from commercial trout breeders in the New 

 England States. Heavy rains and other unfavorable weather con- 

 ditions at the spawning time were important factors in curtailing 

 the production of the pond fishes, and a decrease in their output is 

 to be recorded. 



The investigator from the division of scientific inquiry continued 

 his studies and experiments in connection with the spawning of the 

 rainbow trout mentioned in last season's report, and though certain 

 points of interest and value are indicated, no definite conclusions 

 have as yet been established. Experiments looking to the improve- 

 ments in certain conditions aifecting the fish held in the station 

 ponds were also conducted. These experiments were along the line 

 of attempting to cliange the chemical properties of the water by 

 the addition of certain acids. The results, however, were negative. 



MANCHESTER (IOWA) STATION. 

 [F. E. Hare, Superintendent.] 



A successful season in fish culture at the Manchester (Iowa) sta- 

 tion is to be recorded. The brood stock of all species remained in 

 good health throughout the year, and there was a satisfactory in- 

 crease in the numbers of fish produced for distribution, the increases 

 being especially noticeable with the rainbow and brook trouts. 



The species liandled were the rainbow trout, brook trout, steelhead, 

 small-mouthed black bass, rock bass, sunfish, and pike perch, with 



