USE OF ELECTRICITY IN THE CONTROL OF SEA LAMPREYS: 



ELECTROMECHANICAL WEIRS AND TRAPS 



AND ELECTRICAL BARRIERS 



Five types of mechanical control devices have been developed 

 for reducing the numbers of sea lampreys in the upper Great Lakes: 

 (1) large, permanent-type weirs and traps; (2) and (3) portable-type 

 weirs and traps for medium- and small-size streams; (U) barrier dams; 

 and, (5) dams and inclined-screen traps. Structures (l) through (h) 

 accomplish the destruction of spawning runs or block them from reaching 

 spawning grounds; the inclined-screen traps destroy young, recently 

 transformed sea lampreys on their way downstream to the "big" lakes 

 (Applegate, 1950, 1951; Applegate and Smith, 195la, 195lb; Applegate 

 and Brynildson, 1952; Applegate, Smith, McLain and Patterson, 1952). 



Of these structures, the more or less conventional weirs 

 and traps are adapted to the widest usage in Great Lakes streams. Al- 

 though these devices have proven to be effective and positive instruments 

 for controlling the numbers of sea lampreys^ their operation is expensive 

 and fraught with frequent danger of breakdown under flood conditions with 

 resultant escapement of mature adults to the spawning grounds. 



In an effort to circumvent these difficulties, preliminary 

 tests were performed in 195l to determine if the usual screens or grates 

 of the sea lamprey weir could be supplanted by a simple, alternating 

 current, electrical field which would control all lamprey and fish move- 

 ment in the stream while permitting unhindered downstream passage of 

 flood waters and debris. The results of these preliminary tests were 

 highly encouraging. They demonstrated that an effective and practical 

 electromechanical sea lamprey weir and trap could be built and operated 

 with greater efficiency and at appreciably less cost than the strictly 

 mechanical type control devices. 



In order to develop and improve the structural characteristics 

 of the electromechanical device (electrode pattern, method of electrode 

 mounting, .....) four pilot models of diverse design were installed in 

 streams and tested during the spring of 1952. Descriptions of experi- 

 mental equipment, test procedures, and summaries of results in each year 

 with recommendations for application of several devices in Great Lakes 

 tributaries are presented. 



