Table 1. — Numbers of electrical barriers operated and numbers of streams 

 treated chemically for the control of the sea lamprey in Lakes Superior, 

 Michigaji, and Huron, 1953-6'+ 



Year 



Lake Superior 



Barriers 



AC DC^ 



Streams _ 

 treated' 



Lake Michigan 



Barriers 



AC 



DC^ 



Streams 

 treated 



Lake Huron 



Streams 

 treated- 



1953, 

 195-;. 

 1955. 

 1956. 

 1957. 

 1958. 

 1959. 

 1960. 

 1961. 

 1962. 

 1963. 

 1964, 



10 



'^A 

 36 

 35 

 39 

 45 

 40 

 36 

 29 

 29 

 26 

 22 



2 



7 



11 



11 



11 



9 



9 



9 



10-0 

 28-1 

 15-1 

 1-7 

 5-14 

 8-17 

 8-17 



7 



17 



19 



37 



63 



37 



19 



3 



3 



3 



4 



7-0 

 26-0 



8-0 

 22-0 

 15-12 



""" These DC diversion barriers were installed downstream from the standard 

 AC barriers. 



^ The first of the paired figures is the number of streams receiving the 

 initial application of the chemical, and the second is the number of reappli- 

 cations. Part of the early reapplications corrected faulty first treatments; 

 all others were made to destroy reestablished stocks of ammocetes. 



■^ No reapplications. 



Table 2. — Numbers of spawning-run sea lampreys 

 captured at electrical barriers in 22 tribu- 

 taries of Lake Superior, 1959-64 



rapidly in all sections of the Lake. It is clearly 

 established that the sea lamprey has been 

 brought under control sufficiently well to per- 

 mit once more a good abundance of lake trout. 

 Similar results are to be anticipated in Lakes 

 Michigan and Huron when stream treatments 

 have been completed there. 



The search for selective toxicants did not 

 end at the Biological Station in Hammond Bay 

 when TFM was released for field use. New 

 compounds still are screened in an attempt to 

 find cheaper and more effective materials; 

 even now "second-order" tests are in progress 



with one family of chennicals that offers 

 considerable promise. The Station also con- 

 tinues to test the quality of all shipments of 

 larvicides supplied by chemical firnns for the 

 control program. 



The Hammond Bay staff, despite continua- 

 tion of certain duties, was able to broaden its 

 program to include the study of several prac- 

 tical problems and an expansion of research on 

 the biology of the lamprey itself. An-iong their 

 projects should be mentioned: study of seasonal 

 changes of water quality that influence the 

 biological activity of larvicides; determination 

 of the effects of TFM on warm-water species 

 of fish; development of a synergistic mixture 

 of TFM and a moUuscicide that reduces costs 

 of treatment; description of embryological 

 stages of all species of lampreys resident in 

 the Great Lakes; determination of the effects 

 of tennperature on the ennbryological develop- 

 ment of the sea lamprey; studies of feeding 

 and growth of ammocetes; and determination 

 of biological characteristics of recently trans- 

 formed sea lampreys. 



Still another significant research project, 

 carried on by the staff at the Biological Sta- 

 tion in Marquette is the study of a single year 

 class of sea lampreys established in a section 

 of stream above an impassable barrier. These 

 animals which had completed 4 growing seasons 



