McAtee Bridge to Madison Dam

It is probably pretty safe to assume that Tubifex occurs in all of the Madison River tributaries in this area. At least in the lower reaches as they cross the irrigated parts of the Madison Valley.

  • Blaine Spring Creek- A mid-January sample (313) below the hatchery, had hugh numbers of worms that were mostly Tubifex. (74 of the 126 worms worms that were closely examined). This is typical of many spring creeks in Montana.
  • Bear Creek- Just above its confluence with O'Dell Creek an early November sample (257) found 53 Tubifex in 76 worms mounted on slides. The community is poor in species and typical of Tubifex sites, but not so poor as the joining O'Dell Creek.
  • O'Dell Creek- An early November sample (252) above Bear Creek found about 69 Tubifex in 83 worms mounted on slides. Ilyodrilus templetoni was also present so partitioning the immature worms was difficult. Most of the Tubifex was immature, but far too big to be Ilyodrilus. Ilyodrilus and mostly immature Tubifex in November both indicate warm water conditions. The community is poor in species and typical of Tubifex sites.
  • Moore Creek- In downtown Ennis a November sample (248) found 88 Tubifex among the 117 worms that were closely examined. A random sample of the worms would have found only Tubifex. I picked out the few other worm species from the Tubifex mass under the dissection scope before slide mounting. The community here is poor in species and obviously stressed.
  • Jack Creek- Above the Ennis Lake road, a November sample found 34 Tubifex of 92 worms mounted on slides. The community is depressed, but not terribly so, and it contains a mixture of tolerant and fairly intolerant species. I will try to look for the upstream limit of the Tubifex zone this spring.
  • South Meadow Creek - An large early winter sample (295) from the Ennis Lake road found only low numbers of worms, but Tubifex made up over 20% of the 62 worms found and closely examined. The community here is only a little depressed and may indicate another marginal environment for Tubifex. A little stream protection could go a long way here.

5 JAN 1997, updated on 2 MAR 1997 D.L. Gustafson
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