PROPAGATION AND DISTMBUTION OF FOOD FISHES, 1923. 65 



the total collection amounting to 8,250,000. The State turned over 

 to the bureau 3,200,000 eggs, of which stock 1,500,000 in round 

 nunil)ers were shipped in the eyed stage to other stations of the 

 bureau, over 500,000 going to the Bozeman (Mont.) hatcherj'. 



A number of the stations receiving these eggs, including Spring- 

 ville, sustained unusually heavy losses prior to the hatching period, 

 though tlie fry resulting from them appeared to be normal. The 

 losses may be attributed in part to the fact that many of the eggs 

 were taken late in the season. It has also been noted, with reference 

 to this field, that eggs stripped from fish the second time are not of 

 the best quality. Of the 522,000 eyed eggs retained at the Spring- 

 ville hatchery 83,000 were lost in the course of the incubation period, 

 while the losses in the fry and fingerling stages aggregated 128,900. 

 Shijjments of fuigerling brook trout to the number of 2-48.850, in the 

 Xos. 2 and 3 stages, were made before the end of the fiscal year and 

 61,250 were carried into the succeeding year. The year's output of 

 this species also included 33,600 No. 4 fingerlings,' the product of 

 the previous year's egg collections. These were distributed in July, 

 1922, most of them being returned to Fish Lake and its tributaries. 



The stock of rainbow trout on hand at the beginning of the fiscal 

 \enT( included 637,000 fingerlings No. 3, which were distributed ir. 

 July, 1922, and also 344,000 fry resulting from the spring egg col- 

 lections. The fry did well until about the second week in August, 

 when an abnormal mortalit}^ occurred and continued for some time. 

 No definite cause could be ascribed for it. The entire lot was being 

 carried in the hatchery, which was supplied with intake water, 

 all surface water being excluded, and every eiiort was made to keep 

 the stock in a sanitary condition. The food used was beef hearts, 

 inspected, to which a small proportion of mush was added. The 

 trouble first became evident through the fading of the fish to lighter 

 shades. They gradually refused to eat, became emaciated, and 

 assumed a heady appearance. The center of affection did not seem 

 to lie in the gills. As a rule the losses were larger in troughs where 

 water was being used a second time. The subsidence of the disease 

 seemed to be coincident with the admission of surface water into the 

 intake reservoir and the transfer of the stock to the concrete pond 

 system, and by the middle of September, when the distribution of 

 the fish was taken up, the survivors were in good condition. The 

 output from the lot consisted of 169,300 fingerlings Nos. 2 and 3. 



With the view to profiting by the experience gained the 508,000 

 fry resulting from the rainbow brood stock the following spring 

 were transferred to the concrete pond system and subjected to the 

 conditions that seemed to have afforded relief to the former lot, 

 but without avail. Though a remarkably healthy and active lot of 

 fish during the earlier stages of their growth, they Avere attacked 

 by a somewhat similar epidemic when about H inches long, but with 

 this difference : Fish that apparently were in good health one day 

 would be lying dead in windrows up and down and through the 

 center of the ponds on the succeeding day. After continuing heavy 

 for a few days the death rate would decrease, but almost every lot of 

 the fish was similarly affected on attaining the length mentioned. 

 The total losses on this stock amounted to 314,000. Of the re- 

 mainder 124,000 were distributed as Nos. 2 and 3 fingerlings before 

 the end of the year and 70,000 were on hand at its close. 



