The Lampreys: Two Natives and an Invader

The tributary record, 1979; the lake's standing, 2026

The oldest fishes in this section's surveys are the lampreys, and the record holds two kinds of them. The natives first: the 1979 tributary survey collected lampreys in the drainage's small water — two specimens of an Ichthyomyzon brook lamprey at two localities, and the brook lamprey Lampetra lamottei at Turkey Creek, a species the Saint Mary's biologists flagged as a new record for the entire St. Joseph River drainage. These are the river's own jawless fishes, small, harmless, and part of the fauna Gerking's generation had not documented here. The invader is the sea lamprey, the parasitic Atlantic species that entered the upper Great Lakes in the twentieth century and against which the Great Lakes Fishery Commission has run its control program — barriers, traps, and lampricide treatments of producing tributaries — for seventy years. The St. Joseph is one of the Lake Michigan program's rivers; the commission's standing for the lake, stated in its October 2026 report, is an adult index of about 20,200 sea lampreys for Lake Michigan, held near its target while the other lakes' indices fell. No treatment date or trapping figure for the Mishawaka reach itself was verified in the record reached, and none is printed; what stands here is the distinction the surveys document — a river whose creeks hold two native lampreys of the scientific record, in a lake system whose managers count the third kind by the tens of thousands and hold it down by program.

Principal sources

1. Marenchin & Sever, "Survey of the Fishes of the St. Joseph River Drainage" — the lamprey records of 1979, incl. Lampetra lamottei as a new drainage record.
2. Great Lakes Fishery Commission — "Sea Lamprey Control in the Great Lakes 2021" (annual report) and the Commission's October 2026 lake-by-lake standing, as reported that month (Lake Michigan index about 20,200, near target).