Figure 57. — Ocqueoc River sea laraprey weir and traps. Lateral 



view showing fine-mesh screens in place for trapping 

 downstream migrants. February, 19^9. 



of the same mesh blockaded the upstreara grates of the upstream 

 traps and lined the downstream grate of the downstream trap; the 

 funnel of the downstream trap was made of the same material. All 

 screen sections were anchored firmly in place and all cracks, 

 joints, or other possible points of escapement in the entire 

 structure were caulked with oakum. To the best of my knowledge 

 the structure was entirely lamprey-tight during the period of oper- 

 ation reported upon here. 



The weir and trap was placed in effective operation on October 

 23, 19hB, and was in continual operation with daily attendance un- 

 til March 20, 19li9 (Figures 57-58). During that period l,l40U newly- 

 transformed sea lampreys were taken as they moved downstream. On 

 March 20, operation of the weir for this purnose was discontinued 

 due to failures in the supporting structure. Severe storms pre- 

 vented the servicing of the weir and removal of captives on only 

 three days during the winter. Otherwise, the presence of snow and 

 ice, even at subzero temperatures, did not hamper seriously its 

 operation although the attendant was frequently very uncomfortable 

 (Figure 58) . All sea lampreys taken were preserved in 10 percent 

 formalin; their number, air and water temperatures, weather con- 

 ditions, and water level gauge readings were recorded for each day. 



- 155- 



