REPOKT OF THE COMMISSIONER OF FISHERIES. 35 



tho youiio: fish resulting from egg collections in this field 

 in building up fishing in the Yellowstone Park, and with this end in 

 view extensive rearing and planting arrangements are under way. 

 Operations in this field during 1923 were undertaken late in May, 

 under the supervision of the district supervisor of the Mississippi 

 Valley rescue station, and 4,794,000 eggs had been secured up to and 

 including June 30. 



Egg collections in the Saratoga (Wyo.) field practically were con- 

 finecl to brook trout and rainbow trout, though a few Loch Leven 

 trout eggs were taken from brood stock carried in the station ponds. 

 The operation of the recently constructed rainbow-trout field sta- 

 tion on Sage Creek during the spring months was made exceedingly 

 difficult by the almost impassable mountain roads, which were still 

 heavily blocked with snow on May 1. The substation was finally 

 reached, as a result of great effort, and a fairly successful season's 

 work was accomplished. Low-water stages in the Pathfinder Reser- 

 voir caused an unusually light run of fish. Eggs were taken through- 

 out the month of May and up to June 7, the total collection amount- 

 ing to 1,237,150. 



The season's output of trout from Manchester (Iowa) station was 

 very seriously curtailed by the flooding of the station reservation 

 during a heavy storm in July, 1922, at which time a large number 

 of brood brook and rainbow trout were washed from the ponds and 

 perished on the station grounds. This loss was partially overcome 

 through the donation of a considerable number of adult iDrook trout 

 by the Sportsmen's Club, of Calmer, Iowa, and small consignments 

 of rainbow-trout eggs received in the following spring from the 

 Madison Valley (Mont.) and Springville (Utah) fields. Part of 

 the fry resulting from these western eggs will be reared for the 

 purpose of replenishing the depleted brood stock. 



During March and April a heavy mortality occurred among the 

 young brook trout at the Hartsville (Mass.) station. It was found 

 impossible to check it by any of the methods of treatment usually 

 applied, and before the distribution could be made the stock had 

 been reduced fully 40 per cent by losses. An investigation showed 

 the presence of the parasite Octomitus, elsewhere referred to in this 

 report, and the mortality was probably due to it, possibly aggra- 

 vated by unfavorable water conditions which may have recluced 

 the resistance of the young fish. 



At the newly established Roaring River auxiliary of the Neosho 

 (Mo.) station the results of the first season in rainbow-trout propa- 

 gation were disappointing, only 958,720 eggs being obtained from 

 the 3,000 adult and 7,000 yearling fish on hand. The low egg pro- 

 duction is attributed to underfeeding of the brood stock by the 

 owner of the ponds. A more satisfactory season's work was ex- 

 perienced at Bourbon, Mo., where another field auxiliary of the 

 Xeosho station was operated for the first time. An arrangement 

 was entered into with the owner of the property whereby the bureau 

 is to receive two-thirds of all the fingerling fish produced. As the 

 site is in the eastern part of the State, its use as a fish-rearing plant 

 will not only effect a material saving in distribution expenses but 

 a greater number of fish than formerly will be available for stocking 

 waters in that section of the country. During the year the bureau 



