46 U. S. BUREAU OF FISHERIES. 



SWANTON (VT.) SUBSTATION. 

 [A. H. DiNSMORE, Superintendent.] 



Fish-cultural work on Lake Champlain during the spring of 

 1922 was a dismal failure, because of the eilects of the unprece- 

 dentedly high-water stages in the Missisquoi River and the lake. 

 The Swanton station was opened March 30, and the first pike perch 

 were taken on April 13. Almost immediately afterwards heavy 

 rains and melting snow brought about flood conditions, abruptly 

 ending all fishing operations. In all, 36,737,000 pike-perch eggs 

 were secured. Following the close of this work 16,200,000 yellow- 

 perch eggs were collected and successfully hatched. 



BRYANS POINT (MD. ) SUBSTATION 

 [L. G. Hareon, Superintendent.] 



Most excellent results were obtained in connection with the work 

 of propagating the yellow perch at this station. Between the 3d 

 and 14th of March 21,620 adult fish of this species, ranging in length 

 from 6 to 9 inches, were collected and placed in live boxes. Ap- 

 f)roximately 75 per cent of them were females, and in the course of 

 the two weeks beginning March 14 they deposited naturally in the 

 live boxes 199,660,000 eggs of fine quality. Some 6,250,000 were sup- 

 plied to other stations of the bureau and to applicants. The re- 

 mainder produced fry to the number of 168,102,000, all of which 

 were distributed in the principal tributaries of the Potomac with 

 the exception of 3,000,000, used in supplying applicants in Pennsyl- 

 vania. 



CONSIDERATIONS CONCERNING WORK OF GREAT LAKES STATIONS. 

 MORTALITY IN PIKE-PEKCH EGGS. 



Every fish-culturist whose work has brought him in contact with 

 the incubation of pike-perch eggs is aware of the high percentage of 

 loss almost invariably sustained, and most of them will doubtless 

 agree that a 50 per cent hatch may be considered fairly successful. 

 The subject has been the ground for several investigations, but no 

 definite conclusions have ever been reached nor any practical reme- 

 dies suggested. In the most recent report ^ on studies of this im- 

 portant point in fish culture, Dr. Franz Schrader and Sally Hughes 

 Schrader conclude that the high death rate is not caused principally 

 by lack of impregnation, as seems to have been generally supposed. 

 They attribute the most important cause to the agency that mani- 

 fests its presence in abnormalities occurring during the early stages 

 of development, which must lead either to malformation or death. 

 They believe that this agency may be traced to the practice of retain- 

 ing captured fish in artificial inclosures, pending the maturity of the 

 eggs and sperm; that the same condition may be induced in fishes 

 retained for undue periods in the fishing appliance used in their 

 capture ; that the present methods, mechanical or otherwise, but ad- 



a Mortality in ril?p-Perch Esss in Hatclierio.s. By Fi-anz Schrader and Sally Hughes 

 Schrader. Bureau of Fisheries Document No. 920, Appendix V, to the Report of the 

 D. S. Commissioner of Fisheries for 1922, Washington, 1922. 



