WHITEFISH FISHERY OF LAKES HURON AND MICHIGAN 



357 



abundance of whitefish on the pound-net (shallow-water) and gill-net (deep-water) 

 grounds of the district and also between the production of whitefish by these two gears. 

 A similar close resemblance between the statistical data for pound nets and gill nets is 

 to be found in other districts. 



It must be remembered also that any assumption of the existence of shallow-water 

 and deep-water stocks of whitefish in northeastern Lake Michigan does not make a 

 similar assumption valid for any other region. In districts H-3 and H-4 of Lake Huron, 

 for example, the simultaneous collapse of the deep-trap-net and pound-net fisheries must 

 be interpreted as strong evidence that both gears drew a large part of their production 

 from the same stock. It is not known, even in northeastern Lake Michigan, to what 

 extent there may be an interchange of individuals between the inshore and offshore 

 groups of whitefish. 



SUMMARY AND COMPARISON OF THE BATHYMETRIC DISTRIBUTION OF 



WHITEFISH IN LAKES HURON AND MICHIGAN, WITH SPECIAL 



REFERENCE TO THE REGULATION OF THE FISHERY 



The present study of the bathymetric distribution of the whitefish was part of a 

 program conducted to obtain reliable data upon which to base a sound regulation of the 

 deep-trap-net fishery. One question was: "What regulation as to the depth of water 

 in which deep trap nets should be fished will serve best the dual purpose of protecting 



/ o o 







<4I 41-60 61 70 71-80 81-90 91-100 101-110 111-120 >1 20 



ct / - 

 5 



MICHIGAN 



<4I 



41-60 61-70 71-80 81-90 91-100 IOIIIO 111-120 >/ 20 

 DEPTH IN FEET 



Figurs 23. — Bathymetric distribution of legal-sized (solid lines) and illegal-sized (broken lines) whitefish in Lakes Huron and Michigan as determined 

 from the combination of the data for all localities, years, and months in each lake. 



