2o The location and extent of potential spawning and larval habitats 

 in the streams of the basin« Criteria used to determine the relative 

 suitability of streams were established by Applegate (1950) and other 

 workers! specific water temperatures^ velocities, and bottom types neces- 

 sary for successful completion of the stream phases of the life cycle 

 were determined o 



3o The best sites for control structures in streams which are 

 apparently suitable or are actually used by sea lampreys for spawningo 



During the summer of 19^0, all of the streams from the Tahquamenon 

 River (Chippewa County, Michc) west to the tip of the Keweenaw 

 Peninsula were examined (figSol-17)o The personnel included, in addition 

 to authors, Clifford Brynildson, Daniel Garn, William Gaylord, Carl 

 Jacoby^ Alberton McLain, and Phillip Parker „ The 19^1 survey was con- 

 ducted by Howard Loeb^ William Gaylord, Carl Jacoby, and George Simmons; 

 this party examined streams in the area between the tip of the Keweenaw 

 Peninsula and the Michigan-Wisconsin border (figs. 1, 18-23) » 



Appreciation is extended to the Institute for Fisheries Research, 

 Michigan Department of Conservation, for data on the Two Hearted River, 

 and to Leo Fo Erkkila of the Fish and Wildlife Service for data on 

 utilization by the lamprey of several streams (table 23=. Alan C. 

 Bennett prepared the maps, and William Gaylord identified lamprey larvae,. 



Digest of principsil findings 



Results of the 19^0 and 195l stream surveys in the Lake Superior 

 watershed are summarized as follows (figSo 2-17 and 18-23): 



Number of streams and tributaries examined ; 



1950s 869 (Tahquamenon River west to the tip of Keweenaw 

 Peninsula) 



195ls 178 (tip of Keweenaw Peninsula west to Michigan-Wisconsin 

 border) 



Of the streams examined in 19?0, detailed data were obtained for 

 330. (Tables I-I6 present information on the 112 streams which possessed 

 some potential for reproducing the sea lamprey„) The remaining 539 

 streams which appear on large-scale maps of the area were found to fall 

 in one of the following categories: 



