The Tveir substructijrs consists of a plank deck, 2 inches in 

 thickness, and 12 feet ivide by 80 feet long, tvhich is anchored to 

 the stream bed by three rovis of Wakefield, piling driven $ feet 

 into the bottom. The plank deck vfas initially flush mth the 

 stream bed. A h inch by 6 inch timber beading is anchored to the 

 "head" and ^tall" of the plan}: deck. 



Large A-frames, sitting on the deck and between the headings, 

 form the supporting members of the superstructure. These are 

 removable, being anchored to the headings by drift pins. Against 

 the upstream face of the A-frames lie sectional steel grates meas- 

 uring U by 7 feet. These grates pivot on their stream-bottom edge 

 and may be throTvn over to lie on the bottom to allow the passage 

 of unusual floods. The spacing between each bar of the grates is 

 1/2 -inch. 



The inside dimension of all traps is U feet by 5 feet. Funnels 

 leading into the traps are of 3/l6-inch mesh hardirvare cloth and the 

 funnel openings measure 1; inches by 12 inches. 



Substructure and superstructure are sealed to the river banks 

 by earth filled abutments, 12 feet i^ide and slightly higher than 

 the treir. A plarJ: catvirall^ for access completes the structure. 



This weir and trap were operated for the capture of the spawn- 

 ing run from l^rch 31-September 39, 19l|.9. Following certain im- 

 provements, the weir functioned satisfactorily and was, like the 

 Carp Creek weir, essentially lamprey-tight. On various dates 

 between llay l5 and July 1$, 19U9, four complete patrols of all sea 

 lamprey spaTmijig grounds dji the Ocqueoc watershed -vvere made. Several 

 spawning areas, used extensively In former years, were visited six 

 or seven times. 



On June 6, 19U9, some evidences of a small escapement above 

 the weir was found in a one-lialf mile stretch below the Ocqueoc 

 Falls. Six nests ivere present, about half completed and without 

 eggs. Two adults, one on each of two nests, were fottnd and removed 

 by spearing. One was a ripe, unspawned male, lU.2 inches long — 

 the other was a ripe, unspavmed female, 12c 5 inches long. Forty- 

 seven sites of very preliminaiy nestin.g activity were likevase 

 observed in this area. Sin.ce a male sea lamprey will frequently 

 make several trial nests before sevMing on a final site, the above 

 figure;? do not imply that an equivalent number of lampreys were 

 present in the watershed. Subsequent vr.sits indicated continued 

 nestjjig activity at five sites but no adults were seen. I estimate 

 from the above observations that not more than ^0, and probably 

 only about 35? sea lampreys passed the Ocqueoc weir. In vievf of the 

 fact that nearly 25,000 sea lampreys were captured by the T;eir and 

 its traps, I consider this escape encouragingly small. 



30 .- 



