An electromechanical iveir -was i:i£"'oalled below the Ocqueoo Tdver 

 Trveir and was operated and tested contiiriously for 6 weeks during the 

 height of the upstream migration of ser. lampreys, l/ 



The objectives in operating thic Control Zone another yeai' are 

 sttrnmarized briefly as follo-vTs: 



(1) To gain additional experisnos in the operation of this 

 type of control and to obtain information on ajdmin- 

 istrative and operationcJ. p:'obleras and costs. 



(2) To ascertain further the e/Veots of the prevention of 

 reproduction by sea lampreys in the streams tributrr;'" 

 to a limited area of shorel:_."ic . 



(3) To continue the development and testing of improvements 

 in design and construction of meclianical control struc- 

 tures ; and 



(U) To provide sites where adcqr.ate checlcing devices (T/eirs 

 and traps) were present foi 'costing other equipment, 

 primarily of an electrical nature. 



Lake Michigan . — Six pc)rtable-t3n.)G r/cirs and traps were agaiji in- 

 stalled and operated by the Wisconsin Conservation Department in 

 streams tributary to Lalce Llichigan. Eocause of high waters these de- 

 vices were installed late and conseqv.<:)is.t?^'- some escapement occiirred, 

 but the majority of the sea lampreyo entsx'ing these streams ivere cap- 

 tured. Two structures were relocated to eliminate spawning which 

 occurred in areas below v/eir locationt: used in 1950. 



The checking weir and traps luxLv. in the Black River, Mackinaw 

 County, Michigan, was installed at a :ic?a- location above the barrier 

 dam in that stream for operation by personnel of the Michigan Depart- 

 ment of Conservation. The purpose of these structures was to deter- 

 mine the effectiveness of a special!;''' dojiigned, low-head barrier dam 

 in blocking upstream movement of spai.rning-run sea lampreys. The oper- 

 ation of this unit was continuous tiu-cughout the season. Although a 

 large run entered the river, no lamr)i'c-)7s vrere taken in the checking 

 weir. The barrier dam was completely effective in blocking the migrants. 



Lalce Superior. — In the Lalce Superior basin the weir and trap in 

 PendiHTs Creek, Chippewa County, viras operated for the second yeai" and 

 captured the entire run. An electrical fish screen and a portable-type 

 weir and trap (checking vreir) were operated in the Chocolay River, 

 Marquette County, Michigan. 



Numbers of lampreys talcen by co:-trol devices . — A total of 7i^j^72 

 spawning-run sea lampreys was captui'Ou in 1951 in 21 control devices. 

 In nearly all streams, the entire spasming runs ivere captured. Of the 



1/a detailed report of the developmeu'; of electrical and electromechan- 

 ical sea-lanprey-control dev:.ces T.i.11 be presented elsevriiere. 



