74 U. S. BUEEAU OF FISHERIES. 



The spawning of the largemouth and smallmouth black bass be- 

 gan about April 20 and extended well into June. Twenty-seven 

 nests of the former species yielded 55,135 young bass, of which 

 15,635 were fingerlings No. 1, while the distributions of the small- 

 mouth bass included 7,450 fingerling fish. An adverse feature of 

 this work was the loss of a material number of adult fish of both 

 species during the breeding season, greatly reducing the output. 

 The most careful observation failed to reveal the cause of the mor- 

 tality. So far as could be determined there were no unusual en- 

 vironmental conditions, and the dead fish appearing on the surface 

 of the ponds had apparently not suffered from disease and bore no 

 discernible evidence of bruises or injuries of any kind. The 500,- 

 000 yellow-perch fry entering into the year's distributions w^ere 

 derived from a consignment of 1,000,000 eggs supplied from the 

 shad station on the Potomac River. 



A number of items of construction work were accomplished during 

 the year, among the most important being the enlargement and deep- 

 ening of two of the ]3onds and the construction and installation 

 of a"400-foot concrete flume to replace the old decayed wooden con- 

 duit for supplying the pond system on the lower level of the station 

 resei-\^ation. The hatching capacity of the station was increased by 

 the construction of a shed"^ building, 40 by 42 feet in dimensions on 

 an 18-inch concrete foundation wall and concrete flooring, to house 

 a supplementary series of troughs. Eighteen additional troughs of 

 galvanized iron were purchased and will be set up in this building 

 as soon as the necessary pipe connections can be made. 



MANCHESTER (IOWA) STATION. 



[F. E. Hake, Suporiutendent.] 



In the latter part of July, 1922, this station was subjected to a 

 heavy downpour of rain, which flooded the reservation within an 

 incredibly short space of time, transforming the entire pond sys- 

 tem into one large lake and permitting the escape of a large per- 

 centage of the fish held therein, among them being many of the adult 

 trout that were being counted on as a source of egg^ supply. One 

 of the direct consequences of this loss was the reduction in the out- 

 put of rainbow trout to less than one-half that of the preceding year, 

 though the prospects up to the time of this occurrence had promised 

 an increased egg production both of the rainbow and the brook trout. 

 Moreover the quality of the eggs secured from the surviving rain- 

 bows was so inferior that only 98,685 fingerling fish were produced 

 and distributed from the ;>5-l:,70(» collected. The greater part_ of 

 the losses among this stock occurred before the hatching period. 

 With the view of replacing the losses of brood fish, selected lots of 

 young trout of both species are being reared, among them being 

 8,200 of the finest brook-trout fingerlings and the entire lot of fry 

 produced from a consignment of wild rainbow eggs, the latter hav- 

 ing been received during the spring from one of the western stations 

 of the bureau. 



The egg collections from the adult brook trout, amounting to 

 133,000, were supplemented by the purchase of 358,000 eggs from 

 commercial trout establishments and the transfer of 235,000 eggs 



