WHITEFISH FISHERY OF LAKES HURON AND MICHIGAN 299 



the investigators to go aboard their boats, by giving specific information requested, and 

 by discussing frankly problems concerning the fishing industry on the Great Lakes. 



The research staff of the U.S. Fisheries Vessel Fulmar obtained data in 1932 on 

 some of the deep trap nets and pound nets fishing in Green Bay and around Gull Island 

 in northern Lake Michigan. 



The general procedure in the field investigation was to observe the lifting of the 

 deep trap nets, to make counts of all fish in the net, and to take notes both from 

 observation and interviews with the fishermen. 



Certain data were, of necessity, obtained from the fishermen. They were: distance 

 and direction from port or from some charted landmark; depth of water in which 

 the net was set; size of mesh (as manufactured) in the lifting pot; depth of lead; and 

 the dimensions of the net. 



Other data were recorded as observed. These included: size of mesh (as found 

 in use) in the lifting pot; preservative with which the twine was treated; numbers of 

 legal- and illegal-sized fish, and of dead, bloated, and gilled fish of each species. 

 Gilled whitefish were measured and weighed whenever possible. When it was impos- 

 sible to measure or weigh the gilled fish, an estimate was made of the numbers that 

 were of legal or illegal size. Lengths, weights, and scales were procured from samples 

 of the catches of whitefish when possible. Few data could be obtained on the sex and 

 maturity of the legal-sized whitefish because practically all were sold in the round. 



The procedure for the study of pound nets was the same as that for the deep trap 

 nets. As these two types of gear are of such similar construction, it has been possible 

 in certain phases of the study to combine the data collected from both. 



The data collected during the course of the 1931-1932 field investigations form the 

 basis of parts III and IV of the present report. 



Statistical investigations also have been made an integral part of the present study 

 of the whitefish fishery of Lakes Huron and Michigan. In order to provide a better 

 background for the understanding of conditions in the recent critical years, a compi- 

 lation was made of all available statistics of production in the United States waters of 

 the two lakes and of production in the Ontario waters of Lake Huron, beginning in 

 1879. These data are presented in part I. 



Detailed statistical analyses have been made of local fluctuations in the produc- 

 tion and abundance of whitefish and in the intensity of the whitefish fishery in the 

 State of Michigan waters of Lakes Huron and Michigan over the period, 1929-1939 

 (part II). These analyses, which were based on commercial fishing reports supplied 

 by the Michigan Department of Conservation, have contributed greatly to the under- 

 standing of the effects of extensive deep-trap-net operations on the general conditions of 

 the fishery. 



The deep trap net. with the effect of which on the course of the whitefish fishery this 

 report is primarilv concerned, was developed by the late John H. Howard at Cape 

 Vincent, N.Y., and was first used by him in Lake Ontario in 1924. By experimenta- 

 tion Mr. Howard discovered that "the bigger the trap the bigger was the catch of fish 

 taken." 2 Accordingly, he built larger trap nets, using his Lake Erie type of trap nets 

 as a pattern, and increased their depth from about 12 feet to as much as 30 feet. This 

 type of net soon was adopted by other fishermen in the vicinity of Cape Vincent, but 

 apparently did not spread to other ports on Lake Ontario. 



The deep trap net was introduced into Lake Huron July 12, 1928, when John H. 

 Howard and his brother, D. C. Howard, set five nets in Thunder Bay off Alpena, Mich 

 Deep-trap-net operations were confined to the Alpena region in 1928 and 1929. In 

 1930. however, an expansion of the fishery got under way, that ultimately carried the 

 deep trap net to all parts of the United States waters of Lake Huron and to most of 

 the important whitefish grounds of Lakes Michigan and Superior. 



In all three of these lakes the deep-trap-net fishery was confined to, or underwent 

 its principal development in, the State of Michigan. Since deep trap nets were never 

 permitted in the Province of Ontario or introduced into the Minnesota and Wisconsin 



2 We are indebted to the late John H. Howard and to J. P. Snyder, former Superintendent of the Federal Fish Hatchery, Cape Vincent. N. V., 

 for information on the deep trap net in Lake Ontario. 



