582 



U. S. BUREAU OF FISHERIES 



LAKE MICHIGAN AND GREEN BAY 



The Lake Michigan and (iieen Bay investigations were also co- 

 operative undertakings, the work being liberally supported finan- 

 cially by tlie Conservation De[)artnients of Michigan and Wisconsin 

 and by a group of four fish net and twine coni])iinies located in the 

 (ireat Lakes area. The twine (companies donated some 90,000 feet 

 of experimental gill lu'tting valued at about $8,200. The Lake 

 Michigan program was designed })rimarily to determine whether it 

 is possible to fish gill nets for chubs, species closely allied with the 

 wliitefish, without destroying large numbers of small, immature lake 

 trout as actually occurs at the present time. This problem in its 

 broader aspects is a comj)licated one and involves not only a study 

 of the selectivity of gill nets of various-sized meshes on lake trout 



KKiURM 4. — The U. S. F. S. Fulnnir cqnipp'ed for pxi>eriin(>ntal Kill-iiff fisliiiiK in 

 Ijiikc MIchiKan. A unjqufl feature of this efiuipment is tlit' drying pchMs for nets. 

 Tliey permit ttio vessel to flsli from a different part eacli day witliout returning 

 to dry nets 



and chubs at various seasons and in various areas, but also a con- 

 sideration of the following questions: Effect of various methods of 

 stringing chub nets cm the catch of lake trout, distribution and 

 migration of chubs and lake trout at various seasons and in various 

 ai'eas of the lake and the factors involved therein (currents, depths, 

 tem])eiatin'e, bottom, i)lankton, food, etc.), races or species of lake 

 tiout, the effect of bait nets on the food su[)})ly of lake trout and on 

 the abundance of chubs, the destructiveness to immature lake trout 

 and wiiitelish of hooks, large-meshed gill nets, poinid nets, and deep 

 trap iK'ts. In addition, as many data as })<)ssible were collected on 

 the natural history and life history of the various species of corego- 

 noids and lake trout. 



The bureau's vessel, Fulmar, a boat 102 feet long, has been fully 

 equipj)ed for experimental fishing and has been manned by experi- 

 enced (commercial fishermen, in addition to the scientific personnel. 

 The Lake Michigan investigations were begun June 17 and discon- 



