PROPAGATION AiSTD DISTRIBUHON OF FOOD FISHES, 1922. *73 



an aggregate output of approximately 1,000,000, and considerable 

 numbers of fish remaining on hand at the end of the year to augment 

 the brood stock or for later distribution. The brood stock of rain- 

 bow trout consisted of 1,900 adult females, some 900 of which were 

 2 years old. These fish yielded 512,000 eggs, and from those eggs 

 retained at the station 95 per cent produced fry. 



The brook-trout brood stock contained in round numbers 1,400 

 females, 1,000 of which were yearlings. From these fish 145,000 

 eggs were taken, all of which were incubated with a loss of 6 per 

 cent. The output of this species was increased by the purchase of 

 some 700,000 eyed eggs from commercial breeders. Steelhead eggs 

 to the number of 25,000 were received from the Birdsview (Wash.) 

 station and incubated without undue loss; the resulting fry will 

 be retained for brood stock. 



Weather conditions were unfavorable during the spring spawn- 

 ing season of the pond fishes, and none of them produced as prolifi- 

 cally as might otherwise have been expected. Successful results 

 were obtained from the rock bass, 72 mature breeders of this species 

 producing 16,650 fry and fingerlings for distribution. Pike-perch 

 eggs to the number of 75,000 were received from the Lake Erie sta- 

 tion, from which 60,000 fry were produced. 



Two concrete ponds, each 21 feet wide by 32 feet long, and 2| 

 feet deep, with concrete sides, were made by combining three of the 

 original nursery ponds into one of these. A portion of the bottoms 

 was left in earth to induce the growth of pond vegetation. Each pond 

 is supplied by three IJ-inch pipes, and they will be used for holding 

 the brood stock when necessary, as well as for the accommodation 

 of fingerlings at other times. Cement kettles were constructed in 

 five of the breeding ponds, and all ponds at the station are now 

 equipped with such kettles. 



NEOSHO (MO.) STATION. 



[Fred .T. Foster, Superintendent:.] 



The station's output of rainbow trout was 57 per cent in excess 

 of that of any previous year, notwithstanding the continued presence 

 of a persistent parasitic affection among the older adults, making 

 it almost impossible to secure good eggs from fish over 3 years of 

 age. During the spring of 1922 an epidemic of " fluke parasites " 

 attacked the fins and gills of the fingerling fish, resulting in some 

 losses. This is the first authentic record of the appearance of the 

 disease here, though from evidence at hand it is believed to have 

 existed to some extent a number of years ago. After experimenting 

 with several remedies, including potassium permanganate, the trouble 

 was finally overcome through the application of a 1 to 15 solution of 

 pure cider vinegar and water. The rainbow trout appears to be 

 finely adapted to the waters of Missouri and the adjacent region, 

 and frequent reports of excellent captures are received, many of the 

 fish taken weighing from 4 to 8 pounds. 



In order to determine the possibilities of brook-trout propagation 

 at this station, a consignment of fingerlings and yearlings of that 

 species was received for a brood stock from the Manchester (Iowa) 

 station late in the year. On arrival the fish were found to be 



