80 U. S. BUREAU OF FISHERIES. 



liatched from an equal number of rainbow-trout eggs would be turned 

 over to the State for distribution. Though the percentage of hatch 

 was in excess of 96, the qualitj^^ of the eggs as a whole was somewhat 

 inferior and the losses of fry prior to the feeding stage were un- 

 usually heavy, especially on one lot that was badly affected by the 

 disease known as " bluesac." The fish were distributed as finger- 

 lings Nos. 1 and 2, the output amounting to 710,066 not counting 

 2,000 that were retained for future use as brood fish. 



The output of black bass of both species amounted in round num- 

 bers to 117,000, or about 16,000 more than were distributed last year. 

 Most of these were shipped in the advanced fry stage. 



WTTHEVILLE (VA.) STATIOlSr. 

 [Chas. B. Grater, Snpprintendent.] 



The output of this station amounted in round numbers to 695,000 

 eggs and fingerling fish, an increase of 63 per cent over the produc- 

 tion of the previous year. About 25,000 of this number represented 

 such pond fishes as the black bass, catfish, rock bass, and sunfish; 

 243,000 were eyed rainbow-trout eggs, and the remainder consisted 

 of fingerling rainbow and brook trout. 



On the stock of 1,044,000 eggs of the rainbow trout secured during 

 the fall there was a loss of 347,500 owing to the presence of large 

 numbers of defective eggs, known as " pinheads.'" Some of this 

 heavy mortality was doubtless due to the advanced age of many of 

 the brood fish, but it ma 3^ also be attributed in large part to the poor 

 physical condition of the brood stock as a whole, brought about by 

 an insufficient water supply during the late summer and early fall 

 when the flow from the spring was at a low ebb. 



For the purpose of ascertaining the percentage of hatch a lot of 

 eyed eggs was planted in a mixture of sand and gravel in one of the 

 ponds. There were no results, but in another lot of the same age 

 placed in nests of screened coarse crushed rock in a trough in the 

 hatchery the mortality appeared to be very small, the fry emerging 

 from the stones with the sac well absorbed within a period of two 

 weeks. 



At the beginning of the feeding stage two lots of fingerlings, 

 equal as to numbers, size, and weight, were selected for the conduct 

 of an experiment made to test the value of a commercial fish food 

 composed of fish and cereal as compared with beef heart, the mate- 

 rial in general use at this station for the feeding of fingerling fish. 

 At the end of 60 days the lot that had been fed on beef heart showed 

 an increased weight of 42.75 ounces as against a gain of 8.35 ounces 

 for the fish receiving the commercial food. A second test was made 

 with two equal lots of fingerlings that had been fed for a period of 

 two weeks on beef heart. At the end of the 30 days' trial the lot 

 that had been changed from the heart to the commercial brand of 

 food showed a gain of only 12.75 ounces while the control lot had 

 increased 24.75 ounces in weight. 



Most of the adult fish at this station have been fed on liver and 

 other slaughterhouse products in the past, but recently a change was 

 made to beef heart mixed with varying proportions of mush. This 

 diet has been found to result in a large production of eggs of good 



