Life History of the Least Darter in Dinner Creek, Becker County, Minnesota By Jay T. Hatch

In order to fill in some of the gaps in our knowledge of darter natural history, a series of studies funded by the Nongame Wildlife Program of the Minnesota Department of Natural Resources was begun in 1983 to elucidate the life histories of all fifteen Minnesota darter species. The approach has been to intensively study different but overlapping assemblages of darter species in geographically disjunct and physically diverse drainages. In the first report on these studies (Hatch 1986), I presented basic life history data for 5 species of darters occurring the Upper St. Croix River drainage (Etheostoma nigrum, Percina caprodes. P. evides. P. maculata and P. phoxocephala). I now report the results of a study of the least darter (Etheostoma microperca) in Dinner Creek, Becker County, conducted from May 1984 through October 1985. The life history of this species has not been studied previously in Minnesota, and has been studied little elsewhere. Burr and Page (1979) studied a population in the Iroquois River, Illinois, and apparently Kossel (1967) and Starostka (1967) studied a population in a pond near the campus of the University of Wisconsin-Stevens Point, although neither published their results (mimeos cited in Lutterbie 1976). Lutterbie (1976) provided additional information on the growth and seasonal gonadal weights of Wisconsin specimens. Petravicz (1936) and Winn (1958) reported on the fecundity and reproductive behavior of least darters from Michigan. This study was originally funded under the title, Comparative ecology of the Iowa darter (E. exile) and the least darter (E. microperca) in Dinner Creek and Lake Itasca." Funding of the study was continued and the study was modified in a subsequent proposal entitled