thereafter only readings at the time of the visit -were recorded 

 in that year. Frequent records were made of the surface water 

 temperatures at the mouth of the creek and in Hammond Bay itself. 

 Water gauge readings were made and recorded in inches and frac- 

 tions and represent absolute depth in midstream just below the 

 vreir. Daily records of ivind and other weather conditions were 

 made and these data were supplemented with similar records main- 

 tained by Mr. G. W. Hansen, liO Mile Point Light Station, Lake 

 Huron. 



Since virtually all sea lamprey migratoi-y activity in Carp 

 Creek occurred during the hours of darkness, the data were 

 arranged so that all individuals entering the trap during any one 

 night were tabulated as a unit. Thus the catches subsequently 

 designated for any given day (which are listed at the time of the 

 morning visit) represent the migration into the trap since the 

 morning visit of the preceding day (approximately 23 clock hours 

 since the trap ivould be closed about an hour each day virhile the 

 fish were being removed). Maximum, minimum, and mean water tem- 

 peratures recorded likeiidse reflect conditions which existed 

 during the 2h-hour period prior to about 3:00 A. M. on any date. 



Ocqueoc River inve s t i gat ions 



The sea lamprey run in the Ocqueoc River during 19h7 and 19U8 

 was not impeded by any weir, trap, or other man-made structure. 

 For this reason, it was used in those years as an area for the 

 study of the migrators'" and spawning habits and spai^vning require- 

 ments of the sea lamprey. In addition to these observations, a 

 series of samples of the sea lamprey run were obtained in 191+7 to 

 augment the materials collected at Carp Creek. In the summer of 

 I9I4.3, a sea lamprey weir and trap was completed in the Ocqueoc 

 River and was operated during the spring and summer of 19h9 to 

 capture the spawning run. Since the data for both streams are com- 

 bined or dravm upon in the subsequent analyses, a brief description 

 of the river and methods and places of collection are presented 

 herewith. Further details of the physical characteristics of the 

 Ocqueoc River vj-atershed vjill be presented in the section on spavm- 

 ing habits and spawning requirements of the species. A description 

 of the sea lamprey runs entering this river in 19UU and 19hS has 

 been published by Shetter (I9li9). 



(1) The Ocqueoc River 



This river is by far the largest stream entering Hammond Bay. 

 It flows in a northerly direction from its headwaters to Ocqueoc 

 Lal-ce and from there, almost due east into the bay. Its watershed 



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