58 U. S. BUREAU OF FISHERIES. 



MANCHESTER (IOWA) STATION. 

 [Frank E. Hark, Superintendent.] 



The output of this station consists of 125,500 eyed eggs of the rain- 

 bow trout and 6T8.585 fry and fingerling fish of the different species 

 propagated. The rainbow-trout brood stock did not yield an alto- 

 gether satisfactory return, there being only 378,600 eggs taken. With 

 the maturity of plans now being formulated a very decided improve- 

 ment in this direction is confidently expected. During the spring 

 25,000 eggs taken from wild rainbow trout were transferred to Man- 

 chester from the bureau's Montana station with the view of infusing 

 new blood in the brood stock, and the product of an equal number of 

 steelhead eggs shipped from the Birdsview (Wash.) station will also 

 be reared with that end in view. The adult brook trout, consisting 

 of 625 2-year-old fish and 35 fish 3 years old and over, yielded 58,000 

 eggs. These fish were again affected by a gill disease just prior to the 

 spawning season and suffered a heavy mortality. Brook-trout eggs 

 to the number of 650,000 were obtained from commercial dealers in 

 Massachusetts and incubated with satisfactory results. The cold 

 weather of the late spring reduced the output of largemouth black 

 bass to 2,500 fingerlings, but better success attended the culture of 

 the rock bass, the distribution of that species amounting to 53,910 

 No. 1^ fingerlings. 



NEOSHO (MO.) STATION. 

 [Fred J. Foster, Superintendent.] 



There was a very satisfactory increase in the output of rainbow 

 trout from this station for the fiscal year 1921. The records indicate 

 that the ef:^^:^ shipments were increased over those of the preceding 

 year l)y 48 per cent, while the increase in the number of fingerling 

 fish distributed was as high as 117 per cent. The improvement was 

 not confined sok'ly to the increased number of fish and eggs produced 

 but has been extended to the quality of the product and a betterment 

 of the condition of the brood stock. 



For a number of years the station has been supplied with water 

 from two sources — ^the Hearell Spring and the McMahon Reservoir. 

 Observations made by the superintendent led to the belief that the 

 eggs of fish held in ponds supplied from the spring were not equal, 

 eitlier in numbers or quality, to those taken from fish in ponds sup- 

 plied from the reservoir. For the purpose of testing the soundness 

 of this theory the following experiment was conducted: A number 

 of 3-year-old rainbow trout from the same hatch, which up to the 

 time of the experiment had been held in the same pond, were divided 

 into two equal lots. One lot was placed in pond No, 18, supplied 

 entirely with water from the McMahon Reserv^oir, and the other was 

 placed in Pond F, supplied largely from Hearell Spring. The eggs 

 obtained from fish held in the McMahon water proved 82 per cent 



