486 U. S. BUREAU OF FISHERIES 



Early in the spring a new and peculiar disease, apparently of nervous origin, 

 broke out among the rainbow-trout fingerlings, not only at the main station but 

 also at the Bourbon auxiliary and at two private hatcheries in Missouri. Strong 

 evidence of the disease was visible in some troughs while in other adjoining 

 troughs there was not the slightest discernible trace of it. It invariably attacked 

 fish of the same size — about 2 inches in length. Its j^resence was first made evident 

 by a marked restlessness and loss of appetite and within a day or two afterward 

 the slightest disturbance, even the passing of a hand over the trough, would 

 cause the affected fish to go into convulsions, the mouth opening, the gills distend- 

 ing, and the fish pursuing a rapid darting and frequently a turning motion. 

 Within a few seconds thereafter the diseased fish would sink to the bottom of the 

 trough and die. The mouth closed at death and the gills became normal but the 

 body invariably assumed a crescent shape as if the muscles along the lateral line 

 on one side had contracted abnormally. If allowed to run its course, the duration 

 of the disease was from a week to 10 days, terminating fatally. The treatment 

 adopted was to darken the troughs on the first appearance of the trouble, care- 

 fully guarding against the slightest disturbance, and discontinue feeding for a 

 period of 36 to 48 hours. At the expiration of that time the covers were carefully 

 lifted and the fish fed lightly on clabbered milk, this diet being continued for 

 two days. In the troughs subjected to this treatment the losses averaged less 

 than 10 per cent, while the rate of mortality in the troughs where nothing was done 

 to check the disease amounted to fully 50 per cent. 



In its work with the pondfishes the station was quite successful, its output of 

 iingerlings being more than 10 per cent in excess of the record of any previous 

 3'ear in its history. The importance of this statement is increased by the fact 

 that over half the production consisted of black bass, for which there is such a 

 heavy demand. The output of bass was four times greater than last year's, 

 and exceeded that of any previous year by a substantial margin. The improve- 

 ment in results, particularly as regards the bass, is attributed to a complete 

 renewal of the brood stock preceded by a period of nearly a year when no bass 

 were in the ponds, the purpose being to break the life cycle of the parasites which 

 have in the past proved such a detriment to the pond work at this station. 



Bourbon {Mo.) substation. — Very gratifying results were attained during the 

 third year of operations at this point. A' total of 1,304,170 rainbow-trout eggs 

 was collected, nearly three times the total of last year, and its entire cost amounted 

 to only $160.44. On reaching the eyed stage, approximately 748,000 of thesfe 

 eggs were distributed to applicants and to other stations of the bureau, while 

 from the remaining stock nearly 60,000 fingerling fish were produced, more than 

 half of them being 6 inches in length when distributed. 



The health of the brood stock of rainbow trout remained good throughout the 

 year, though considerable losses were sustained among the fingerlings owing to 

 the development of crystals in the kidneys. The few parasitic attacks en- 

 countered were easily controlled bj^ the application of vinegar baths, but no en- 

 tirely satisfactory remedy could be found for combating the kidney affection. 



Langdon {Kans.) substation. — In the conduct of work at this point greater 

 difficulty than last year was experienced, owing to the larger number of ponds in 

 operation and the scarcity of experienced help, the services of only one trained 

 fish-culturist and two temporary assistants being available. Despite these handi- 

 caps and the further fact that climatic conditions during the spawning season of 

 the black bass were unfavorable, the output exceeded last year's and the results 

 were accomplished at a cost of $2.40 less per thousand than last year's cost, 

 which amounted to $32.68. In arriving at this cost, salaries of the statutory 

 employees engaged in the work were not considered. 



White Sulphur Springs (W. Va.) Station 



[Edw. M. Haynes, Superintendent] 



The methods employed in the fish-cultural work at this station did not vary 

 in any essential respect from those of recent years. Three species of trout were 

 handled — brook, rainbow, and Loch Leven — and of these only the rainbow trout 

 originated from eggs produced on the reservation. Because of the heavy mor- 

 tality invariably experienced in the many attempts that have been made to hold 

 adult brook trout through the reproductive season, it has been found advisable 

 to restrict such work to an experimental basis. During the year all brook trout 

 eggs handled — 1,741,000 — were secured either by purchase or by exchange for 

 eggs of other species. For several years the station has accomplished quite 

 extensive brook-trout work through cooperation with the West Virginia State 



