Trophic status of southeastern Lake Michigan based on the Chironomidae (Diptera)

TitleTrophic status of southeastern Lake Michigan based on the Chironomidae (Diptera)
Publication TypeJournal Article
Year of Publication1985
AuthorsWinnell MH, White DS
JournalJournal of Great Lakes Research

Chironomids and oligochaetes were identified from a total of 2.432 samples collected at depths < 42 m over a 9-year period in southeastern Lake Michigan. Each of 13 chironomid taxa was assigned a trophic indicator status based on density trends among samples characterized by oligochaete trophic indices in the ranges <0.50 (Type 0), 0.50-1.50 (Type 1), and > 1.50 (Type 2). A trophic index based on the chironomid fauna was generated for year, depth intervals, and combinations of years and depths. When averaged over all years, the trophic index at the 8- to 24-m depth interval was 1.26, indicating mesotrophic conditions in this portion of the littoral and sublittoral of southeastern Lake Michigan. Similarly, at depths > 28 m the trophic index value was 0.41, suggesting oligotrophic conditions in the profundal. No annual trophic status trends were evident.