J. Great Lakes Res. 19(3):625-629 Internal. Assoc. Great Lakes Res., 1993 NOTE Evidence of Spring Spawning Lake Trout in Lake Superior Charles R. Bronte United States Fish and Wildlife Service National Fisheries Research Center - Great Lakes Ashland Biological Station 2800 Lake Shore Drive East Ashland, Wisconsin 54806 ABSTRACT. In 1992, the U. S. Fish and Wildlife Service began research on the life history, popula- tion dynamics, and stock delineation of siscowet lake trout Salvelinus namaycush siscowet in Lake Supe- rior. Sisco wet were captured with gill nets in 80-150 m of water on 23-26 April 1992 north of the Apos- tle Islands in western Lake Superior. Of 91 captured siscowets, one male had fully developed testes in nearly ripe condition and one female had eggs running from the vent. This observation represents the earliest dates that lake trout of any morphotype have been found in spawning or near-spawning condi- tion. INDEX WORDS: Siscowet lake trout, spawning, Lake Superior. INTRODUCTION Spawning times of lake trout Salve linus namay- cush have been well documented for populations from inland lakes and the Laurentian Great Lakes. Reported spawning dates are in September (Loftus 1958, Paterson 1968), October (Dymond 1926, Van Oosten 1934, Eschmeyer 1955, Martin 1957, Raw- son 1961, DeRoche 1969, Peck 1986, Sly and Wid- mer 1984), and November (Van Oosten 1934, Greeley 1936, Eddy and Surber 1947, Hacker 1957, Peck 1986). The race of lake trout referred to as the "humper" (Rahrer 1965), found near Isle Royale in Lake Superior, and lake trout from Great Bear Lake (Miller and Kennedy 1948) are known to spawn in August. The latest reported dates of spawning by lake trout are in November and December in Os- tego and Keuka lakes in New York State (Royce 1951). In Lake Superior, Eschmeyer (1955) inferred from the condition of gonads from numerous lake trout captured during 1950-1954 that spawning oc- curred from June to November. Eschmeyer's earli- est collection of lake trout in spawning condition 625 (ripe; free-flowing eggs or milt) was on 8 June 1953 from Isle Royale, and these fish were reported to be "humpers." Historically, Lake Superior contained many mor- phologically distinct varieties of lake trout that oc- cupied specific depths and spawning locations (Eschmeyer 1957, Khan and Qadri 1970, Goodier 1981). Of these, the siscowet Salvelinus namaycush siscowet is distinguished by its preference for wa- ters deeper than 80 m, and by the presence of ex- cessive fat in the flesh and viscera (Eschmeyer and Phillips 1965). Agassiz (1850) and Khan and Qadri (1970) discuss morphometric and meristic charac- teristics of the siscowet. Little is known about the life history of siscowets even though this form is probably one of the more abundant morphotypes of lake trout, both now and historically, in Lake Superior. This fish is generally thought to spawn in November, but Eschmeyer (1955) reported capturing two nearly ripe females as early as July. In early September 1992, I cap- tured many siscowets in ripe condition north of the Apostle Islands in western Lake Superior (unpub-