From the April 8 1940 Toronto Daily Star:
Ernst Vierkoetter (1901-1967) has a Wikipedia entry in German but not in English! He swam the English Channel in 1926 (holding the speed record for 20 years), won the first CNE marathon swim in 1927, and then settled down in Toronto to a career as a swimming instructor. His nickname was “The Black Shark Of Germany”, which is a pretty cool nickname.
The Torontoist has a long article on the 1927 marathon swim, if you want to know more.