312 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Figure 4. — Map showing the statistical districts of the State of Michigan waters of Lakes Huron and Michigan. 



tricts natural divisions from the standpoint of both fishing grounds and fishing opera- 

 tions. 16 For some purposes the data for the separate districts have been combined to 

 provide more general information for different regions of the lakes and for the entire 

 lakes. For convenience, the districts will be designated in later discussions by the 

 initial letter of the lake and the number of the district. For example, the third district 

 of Lake Huron will be termed H-3, the fifth district of Lake Michigan, M-5,***. 



PRODUCTION 



The production was tabulated according to gear for each month. The only im- 

 portant gears used for the taking of whitefish are the large-mesh gill net (4^ inches 

 or larger, stretched measure), the deep trap net, and the pound net. The discussion in 

 this paper will be concerned chiefly with annual totals of the catch of the different gears 

 and of all of them combined. Data on monthly yields will be confined to the discussion 



18 Hile and Duden doc. cit.) stated that Lake Michigan had bsen divided into 11 statistical districts. Experience revealed, however, that certain 

 of the original tentative divisions were not practical. Changes of boundaries and combinations of areas have reduced the number of statistical dis- 

 tricts in Lake Michigan to eight. The six atetistical ilistrirts of Lake Huron all proved satisfactory as originally defined. 



