REPORT OF THE COMMISSIONER OF FISHERIES XXI 



The total number of larval mussels released in a state of parasitism 

 on livin<;^ fishes amounted to 1,335,595,300 for the season, as compared 

 with a total of 2,048,977,1)10 for last year. 



PROPAGATION OF FISHES OF INTERIOR WATERS 



Collections of eggs at stations where brook, rainbow, blackspotted, 

 and Loch Leven trout and the landlocked salmon are propagated 

 amounted to 78,849.670, or nearly 31,000,000 in excess of the corre- 

 sponding figures for 1923. This large percentage of gain is attribut- 

 able to the greatly increased collections of blackspotted-trout eggs 

 in the Yellowstone Park and to the heavy yield of Loch Leven trout 

 eggs in the newly opened field in Madison Valley, Mont. 



As in the past, brook and rainbow trout eggs were collected in 

 Utah fields in cooperation with and under the direction of the Utah 

 fisheries department. The stock of rainbow-trout eggs was aug- 

 mented by the collection of 1,121,700 eggs. 



During the entire season of 1923 fish-cultural work in the Yellow- 

 stone Park was directed by the district supervisor of the Mississippi 

 River Rescue Station. The field of operations was widened to in- 

 clude practically all streams flowing into Yellowstone Lake, and as a 

 result of such extension and of some improvements effected in the 

 method of capturing brood fish, egg collections of the blackspotted 

 trout amounted to 31,570,000. In view of the difficulty of transport- 

 ing fry for stocking many of the mountain streams of tlie park, eyed 

 eggs were planted in the more inaccessible waters. Careful obser- 

 vation of plants of this character, which has been made from time 

 to time, has demonstrated that the results are practically as good as 

 where fry are planted, and the saving in distribution costs by this 

 method amounts to considerable. 



Very satisfactory results attended the initial season's operation of 

 a field station in Meadow Creek, a tributary of the Madison River, in 

 Montana, where Loch Leven trout eggs were secured during October 

 and November, 1923. 



About the usual numbers of brook trout and rainbow trout were 

 produced at the stations located at Wliite Sulphur Springs, W. Va,, 

 Erwin, Tenn., and Wytheville, Va., and the Neosho (Mo.) station 

 was able to augment its collections of rainbow-trout eggs consider- 

 ably through the operation of the substation established last year at 

 Bourbon, Mo. The outcome of the year's work at this auxiliary ex- 

 ceeded that of 1923 by more than 100 per cent. 



Notable results in pondfish culture were attained at the Louisville 

 (Ky.) station; at Lakeland, Md., near Washington, D. C. ; and at the 

 Langdon (Kans.) auxiliary of the Neosho (Mo.) station. The Louis- 

 ville station exceeded its record output of smallmouth black bass in 

 1923 by over 100,000; the outcome of the initial year's Avork at Lake- 

 land was remarkably good, Avhile approximately 100,000 bass, crap- 

 pie, and sunfish fingerlings were distributed as the result of the first 

 year's operations at the Langdon substation under Government 

 auspices. ' 



During the period from March 6 to 29, inclusive, l)ufTalofish eggs 

 approximating 277,000,000 were collected in the Atchafalaya (La.) 

 field. 



