Presque Isle County, in these years. Supplementary information 

 of a similar nature tras gained in the Ocqueoc River, also in 

 Presque Isle County. Later disciossions of spamiing habits and 

 spawning requirements of the sea lamprey are based on data 

 collected in 19lt7 and 19U8 only. Many other observations made 

 during all periods, in these and other localities, are incorpor- 

 ated T/shere it seems most pertinent. 



These studies were undertaken in an effort to obtain more 

 precise information than heretofore existed of that phase of the 

 life history of the sea lamprey beginning when it enters streams 

 to spatm. The information obtained has become of paramoimt impor- 

 tance beca\;ise of the mdely publicized demands for the control of 

 this fish predator -nhich have specified the construction of "lamprey 

 weirs" for the capture and destruction of spawning populations. 

 The investigations undertaken at Carp Creek and the Ocqueoc River 

 were designed to learn the requisites of an effective sea lamprey 

 weir on a small and on a large stream, the cost of such structures, 

 and problems in their operation and maintenance — in addition to 

 the biological information which would be forthcoming through the 

 operation of these structures. It was also intended that the re- 

 peated use of these weirs in succeeding seasons might provide some 

 index of the relative abundance of the sea lampreys in the general 

 area of northern Lake Huron in those years. It would be of obvious 

 value to know if the population is increasing or decreasing, or if 

 it has become relatively stable in numbers. Furthermore, continued 

 operation of these weirs over a period equivalent to at least one 

 larval cycle might provide a test as to whether the "home stream" or 

 "parent stream" theory applied to this species in any degree o 



The general area of the Ocqueoc River and Carp Creek --jvatersheds 

 was selected for study because of the intense local interest in the 

 sea lamprey problem. This interest was engendered by the large 

 runs which entered the Ocqueoc River in increasing numbers during 

 the past decade. In the spring of 19kk and again in 19U^, the East 

 Presque Isle County Sportsman's Association operated a weir in the 

 loi?er Ocqueoc River in cooperation with the Department of Conserva- 

 tiono In each year, a fair proportion of the sea lamprey run was 

 captured (Shetter, 19h9). 



From 19U6 to IPUS no weir was in operation for the capture of 

 spawning migrants in the Ocqueoc River. The construction of a perma- 

 nent sea lamprey "vreir in this river was undertaken in the summer of 

 19hQ by the United States Fish and Wildlife Service. After comple- 

 tion of this structure in September of that year it was turned over 

 to the Michigan Department of Conservation for operation and main- 

 tenance for a ten-year period. 



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