488 



IT. S. BUREAU OF FISHERIES 



following May the station received a shipment of 25,000 eggs of wild rainbow 

 trout from tlie Springville (Utah) field, and the 15,000 fingerlings derived from 

 this stock were on han.d at the close of June. 



In order to test the efficacy of cod-liver oil and yeast in maintaining the health 

 of fish, 300 adult rainbow trout, equally divided as to sex, were segregated in 

 one of the ponds for some time prior to the spawning season, an.d were fed a 

 diet of beef heart mixed with these materials in the proportion of 2 parts oil and 

 4 parts yeast to 100 parts of the heart. That the food is beneficial was clearly 

 shown by the improved results at spawning time, the eggs from the trout used 

 in the experiment being superior to those from the control lot (fed exclusively 

 on beef heart), both as to quality and quantity. 



The disease known as Octomitus, prevalent at this station during the two 

 preceding years, made its appearance again, somewhat earlier than usual, and 

 considerable numbers of fingerling fish were lost as a resu.lt of its ravages. 



With the view of ascertaining the relative value of their spawn, brood rainbow 

 trout of various ages were segregated in different ponds and their eggs developed 

 in separate troughs. The mortality among eggs from 3-year-old and 4-year-old 

 fish did not vary greatly, amounting to 43.3 and 43.61 per cent, respectively. 

 The loss among the 6-year-old fish was 40 per cent, while 573^ per cent of the 

 eggs taken from fish 7 years of age proved worthless. 



In addition to its work with the rainbow trout, the Wytheville hatchery in- 

 cubated 31,000 brown-trout eggs of inferior quality, the product of 900 2-year-old 

 fish held in the station pounds, as well as 400,000 brook-trout eggs purchased 

 from a commercial fish-culturist in Massachusetts. The latter were of an 

 excellent quality yielding a high percentage of fingerling fish. 



The outcome of the year's work in the propagation of the warm-water pond- 

 fishes was comparatively successful. Besides an output of more than 2,000 

 advanced fingerling largemouth black bass in the fall of 1924, 232,000 fry and 

 No. 1 fingerling fish of that species were distributed at the close of the year, this 

 stock being the progeny of 250 adult bass that spawned during the spring in a 

 single large pond. The distributions also included limited numbers of rock bass, 

 bream, and catfish. 



PONDFISH-CULTURAL STATIONS 



The results of the year's work at the seven mam stations and five 

 auxiharies included in this classification were quite satisfactory, the 

 total output exceeding that of the previous season by approximately 

 343,000 lish. Owing to the impossibility of obtaining an adequate 

 stock of brood black bass, the work with that fish was considerably 

 curtailed at some points. Following is a statement of the aggregate 

 output of these stations, by species, during the fiscal vears 1924 and 

 1925: 



Cold Spring (Ga.) Station 



[Chas. a. Bullock, Superintendent] 



In the work of propagating the largemouth black bass it is the practice at 

 this station to collect all brood fish at the close of a breeding season and store 

 them in ponds until the approach of the next spawning period in February. 

 This makes it possible to allow all the other ponds on the reservation to remain 

 dry for approximately six months of the year, thus tending to correct any acidity 



