Table 2. 



-Results of bioassays in water from the Betsy River (Chippewa County, Michigan) 

 and the Sucker River (Alger County, Michigan) 



The treatment of stream B normally would offer 

 no difficult operational problem and treatment of 

 stream C usually could be completed successfully. 

 The permissible additional flow in stream C is, how- 

 ever, the lowest that is normally considered accept- 

 able. If treatment at a value of less than 1. c. f. s. 

 of additional permissible flow cannot be avoided, 

 extreme care must be exercised to insure that con- 

 centrations in the stream remain within the working 

 range. 



The degree to which activity, and with it the 

 working range and permissible additional flow, may 

 vary from time to time in a particular stream is il - 

 lustrated by the actual records for two Lake Superior 

 tributaries (table 2). The bioassays on the Betsy 

 River produced working ranges from to 3. 5 p. p. m. 

 and additional permissible flows of 0. to 2. 3c. f. s. 

 This variability of results sometimes makes it nec- 

 essary to complete a number of bioassays in a 

 stream to determine optimum conditions and time 

 for stream treatment. In the Sucker River (Alger 

 County, Michigan), on the contrary, the bioassay 

 tests consistently indicated favorable conditions 

 for treatment. 



ACKNOWLEDGMENTS 



All rainbow trout used for bioassays were sup- 

 plied by the Michigan Department of Conservation 

 or the Wisconsin Conservation Department. Numer- 

 ous members of the sea lamprey control staff helped 

 in the construction and operation of the mobile lab- 

 oratory. We acknowledge especially the assistance 

 of Jerome Zimmerman, Robert Soucy, Richard K. 

 Kanayama.and Wesley J. Ebel. 



LITERATURE CITED 



Applegate, Vernon C. , John H. Howell, James W. 

 Moffett, B.G.H. Johnson, and Manning A.Smith 

 1961. Use of 3-trifluormethyl-4-nitrophenol as 

 a selective sea lamprey larvicide. Great 

 Lakes Fishery Commission, Technical 

 Report No. 1, 35 p. 



Applegate, Vernon C. , John H. Howell, and Manning 



A. Smith 



1958. Use of mononitrophenols containing halo- 

 gens as selective sea lamprey larvicides. 

 Science, vol. 127, no. 3294, p. 336-338. 



Braem, Robert A. , and Wesley J. Ebel 



1961. A back -pack shocker for collecting lam- 

 prey ammocetes. Progressive Fish- 

 Culturist, vol. 23, no. 2, p. 87-91. 



MS #1178 



GPO 9 28 169 



