ABSTRACT 



An inclined -screen trap was installed on the Carp Lake River, Emmett 

 County, Michigan, in the spring of 1948 and has been in almost continuous 

 operation since that time. The major goal of this project --a precise deter- 

 mination of the length of the larval life of the sea lamprey --was not attained 

 because of the contamination of the stream above the dam with spawning 

 lampreys. The lampreys and other fishes collected in the trap did, however, 

 provide extensive and valuable biological information. The present report 

 documents much of the information, largely in tabular form, accumulated 

 over the operating seasons, 1948-49 through 1957-58; the amount of detail 

 has been varied according to the importance of the topic under consideration 

 or the amount required to bring out a particular point. 



Records given for lampreys include-, annual catches of sea lamprey, 

 American brook lamprey, silver lamprey, and of larval lamprey, not fully 

 separated by species, 1948-49 through 1957-58; daily record of catches of 

 recently transformed sea lampreys, water temperature, water level, weather, 

 and, for some seasons, information on length, 1951-52 through 1957-58; 

 length -frequency distribution of recently transformed sea lampreys for 8 seasons 

 of the period, 1948-49 through 1957-58; mean weights and ranges of weight of 

 samples of recently transformed sea lampreys in 6 seasons of the period, 1948-49 

 through 1957-58; trend in the monthly average length of recently transformed 

 sea lampreys, October 1954 through April 1955; semi-monthly totals of catches 

 of larval lampreys (sea lamprey and American brook lamprey, combined), 

 1948-49 through 1957-58; monthly length -frequency distribution of larval 

 lampreys (same 2 species), November 1949 through June 1950. 



Data on other fishes included semimonthly totals of catches of individual 

 species each season 1948-49 through 1957-58; some information was given on 

 lengths. Altogether, 22 species other than lampreys were caught in the traps. 



