The Madison River above Hebgen Reservoir

Baker's Hole

The Madison River begins with the confluence of the Gibbon and Firehole Rivers in Yellowstone Nation Park. I have no samples upstream of Baker's Hole Campground, which is just outside the park, near the US 191/287 crossing and not too far above of Hebgen Reservoir. I may try to work in the park in 1997.

At the Baker's Hole, I have 4 samples (44, 125, 146 and 221), all with large numbers of worms. I have closely examined 440 worms, emphasizing anything the might be Tubifex, but I have not found a single positive Tubifex. There are some immature worms that could be Tubifex, but they are small even as they approach maturity, and they are most likely are Ilyodrilus templetoni, which is confirmed from the site. This species prefers warmer water than Tubifex does, but they can occur together. I took Ilyodrilus templetoni in both 1995 samples, but neither 1996 samples, even though they were bigger and better samples. This is consistent with temperature and flow differences between the years. Tubifex should have been favored in 1996, but it was still not found.

The benthic community here is not a rich one and is quite similar to many communities with Tubifex. The reasons for this are likely the abnormal water temperature and chemistry from the Yellowstone thermal springs. The affects of the invading New Zealand mudsnail, Potamopyrgus antipodarum (Gray) may be very important here. I collected over a liter of the small snails in my last worm sample! For now, it looks as if there is little reason to expect Tubifex in the Madison River above Hebgen. That should be the upstream limit of the disease.

Aquatic Oligochaete species list

5 JAN 1997 D.L. Gustafson
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