This is a supplement to the report of the International Board of Inquiry relative to the preservation and development of the Great Lakes fisheries as provided by an exchange of notes between Canada and the United States on February 29, 1940. The report aimed to present in a very brief manner the background of the establishment of the Board, its program, and the fishery problems that confronted it with particular reference to the international point of view. (See Contribution #100.) The Board, however, recognized the significance and import of those problems and data more or less peculiar or applicable largely to each country. It was, therefore, agreed that the representatives of each country should, if they deem it desirable, submit to their respective governments a supplementary report to cover the basis of action in greater detail than it was possible in a joint report. The United States members believed it advisable not only to publish detailed statistics of catch, but also other information deemed pertinent for a full understanding of the Great Lakes fishery problems from the United States point of view.