Aquatic Invertebrates of Montana

Montana Whirling Disease Positive Sites

The Montana Department of Fish, Wildlife and Parks has reported the following 38 sites to be positive for the parasite Myxobolus cerebralis through December 1996. Actually they count 39, but I am missing one!

For each of these sites I am giving my predicted Tubifex status whenever this is possible and fair. I am using "no prediction" for all other cases. My prediction is based on my observation of the site in the field. The observed Tubifex status is based on all fully processed samples. I will also note the probable cause for Tubifex in each case.

I am not currently working on lakes or reservoirs, except for shoreline areas. Based on the literature, I now assume that Tubifex occurs in the deep parts of most of our lakes and reservoirs even though I generally cannot find it in shallow areas. If you are working on the benthos of Montana Lakes, I would love to see some of your worms!

Observed Tubifex status

1. unsampled- no worm sample yet taken.
2. unknown- worm sample taken, but not yet processed.
3. positive- Tubifex identified from that site.
4. possible- some worms look like Tubifex, but there were no mature specimens for positive ID.
5. negative- no worms found that even might be Tubifex.

Mississippi Drainage

• Beaverhead Drainage (Tubifex Sites and Status Map)
  • Big Sheep Creek- predict positive; observe positive; probable cause is grazing.
  • Birch Creek Reservoir-
  • Blacktail Deer Creek- predict positive; observe positive; probable cause is grazing.
  • Clark Canyon Reservoir-
  • Grasshopper Creek- predict positive; observe positive; probable cause is grazing.
  • Horse Prairie Creek- predict positive; observe positive; probable cause is grazing.
  • Poindexter Slough- predict positive; observe positive; probable causes are springs and grazing.
  • Red Rock River- predict positive; observe possible; probable causes are river regulation and grazing. This is a long river that likely has Tubifex positive and Tubifex negative sections. For example, the outflow of Lima Reservoir was negative in the autumn 1996. I will match up with the fish data when the sites are all known.
  • Red Rock Creek- predict positive; observe possible; probable cause is grazing. There is little doubt of Tubifex above the upper Red Rock Lake, but I have not been there during good Tubifex sampling season. In fact, it is a little hard to get there during good Tubifex sampling season!
• Jefferson Drainage (Tubifex Sites and Status Map)
  • Boulder River- predict positive; observe positive; probable cause is grazing.
  • Hells Canyon Creek- predict negative; observe positive; no probable cause. We need to look for an upstream problem on this stream. The lower part of the streams looks nice, but the invertebrate community is typical of Tubifex sites.
  • Jefferson River- predict positive; observe positive; probable causes are regulation and grazing.
  • Ruby River- predict positive; observe positive; probable causes are regulation and grazing.
  • Ruby Reservoir-
  • South Fork Boulder River- predict positive; observe positive; probable cause is grazing.
  • Whitetail Creek- predict positive; observe positive; probable cause is grazing.
  • Willow Creek- predict positive; observe positive; probable cause is grazing.
  • Willow Springs- no prediction; observe unsampled; no probable cause.
• Madison Drainage (Tubifex Sites and Status Map)
  • Blaine Spring Creek- no prediction; observe unsampled; no probable cause. I think this is a well known Tubifex site, but I have not been there.
  • Cherry Creek- predict positive; observe positive; probable cause is grazing.
  • Jack Creek- predict positive; observe positive; probable cause is grazing.
  • Madison River- predict positive; observe positive; probable causes are regulation and grazing.
  • Moore Creek- predict positive; observe positive; probable causes are grazing and urban impacts.
  • O'Dell Creek- predict positive; observe positive; probable causes are springs and grazing.
  • West Fork Madison River- predict positive; observe positive; probable causes are grazing and logging.
• Missouri Drainage (see also my Little Prickly Pear Creek and Missouri River Project)
  • Little Prickly Pear Creek- no prediction; observe positive; probable cause is grazing.
  • Missouri River at Craig- predict positive; observe positive; probable cause is regulation.
  • Hound Creek- predict positive; observe possible; probable cause is grazing. The lowest section of this stream is a disgrace! It contained a 2 species worm community with Limnodrilus hoffmeisteri and large immature tubificid with dorsal hairs. There is little doubt that these are Tubifex tubifex. The September 6 collection is too early to get mature Tubifex in a stream like this one.

Columbia Drainage

• Swan Drainage
  • Swan River- predict negative; observe possible; no probable cause. I have not been able to find positive Tubifex in the Swan River. The Tubifex and WD problem might be with some of the tributaries. Porcupine Creek, for example looks suspect. I have not done much work in the area.
• Blackfoot Drainage
  • Cottonwood Creek- no prediction; observe negative; no probable cause. At Woodworth there is no sign of Tubifex. I do not known where the fish sample was taken.
• Clark Fork Drainage (Tubifex Sites and Status Map)
  • North Fork Flint Creek- predict negative; observe positive; no probable cause. This does not look very much like a Tubifex stream, but it is. The stream has a rich community, but low total invertebrate density. An upstream disturbance should be looked for.
  • Georgetown Lake-
  • Flint Creek- predict positive; observe positive; probable causes are springs and regulation.
  • Staurt Mill Creek- no prediction; observe unsampled; no probable cause. I could not find the creek when I was apparently right at it.
  • Racetrack Creek- predict positive; observe possible; probable cause is grazing. The lowest part of this stream in late autumn 1996 does not look very much like Tubifex could support WD. There were some signs that the stream may have been dry in the summer at this site. There were 8 other oligochaete species present besides immature worms that might be Tubifex. I do not known where the fish were sampled at this time. The middle parts of this drainage most likely have lots of Tubifex.
  • Warm Springs Creek- predict positive; observe possible; probable causes are many. Worm density at the town of Warm Springs on 29 OCT 1996 was so low that no mature Tubifex was found.
  • E. Fk. Rock Creek- predict positive; observe positive; probable causes are regulation and grazing.
  • Clark Fork River- predict positive; observe positive; probable causes are many.

Summary

Of the 39 WD positive sites:

• 1 site is unknown to me.
• 4 sites are lakes or reservoirs that I have not adequately sampled.
• 3 streams are not yet sampled (Blaine Spring Creek, which I have heard it is a good Tubifex site; Willow Springs Creek, which I have not yet found. Staurt Mill Creek, which I also have not yet found, but was very close).
• 31 have been sampled for oligochaetes and of these:
  • 24 sites are Tubifex positive
  • 6 sites had possible Tubifex, but no mature worms for positive identification
  • 1 sites was negative, even negative for all tubificids. This site was probably not located correctly. Of 29 sampled sites with fair predictions, I made only 3 negative predictions, that is, WD positive sites look like good Tubifex sites. In fact, the subtitle for this page could be "Great Mudholes of Montana". When first given the list of WD positive sites I was surprised by how few of the streams I knew. I spend several weeks each year sampling water bodies in Montana. Now it is not such a surprise, these are exactly the streams I skip while looking for interesting and seldom collected species!

    Two of the 3 negative predictions are already proven wrong by the samples (Hells Canyon Creek and North Fork Flint Creek). I guess you really do need a sample! Both of these sites likely have unknown upstream disturbances. I will follow up on these. That leaves only 1 of my negative predictions still standing, the Swan River, and it already has possible Tubifex. I will try to take a good look at the Swan River drainage this spring. I suspect that some of the tributaries might be the real problem.

    Of my 26 positive predictions with samples, 21 are already validated by the samples. That leaves 5 positive predictions not yet verified. You can never be sure of a negative sample- field experience will continue to be important here. All 5 of these sites alreadly have possible Tubifex, but with no mature specimens. Three of these (Red Rock Creek, Red Rock River and Hound Creek) are almost certainly Tubifex positive, but my samples came at bad times or they were too small. That leaves only Racetrack Creek and Warm Spring Creek more than the slightest doubt. I will follow up on all of these.

    At Cottonwood Creek, I could not give a fair prediction, but I got a good Tubifex negative sample. There were no species of Tubificidae, only the earthworm Eiseniella tetraedra (Savigny) and Enchytraeidae as is quite typical of healthy, cold streams. I suspect I may have been to far upstream or even had the wrong stream. I have not yet be able to verify the location of fish sample.

    While there are still some loose ends here, the field evidence continues to build that T. tubifex is the only important worm host for the whirling disease parasite in Montana, and that Tubifex is limited to degraded communities. By my own simple evaluation of the sites, grazing is the most frequent problem at WD positive sites. River regulation follows next, but it can affect bigger streams and it may help intensify grazing impacts. Natural springs and urban impacts contribute to the problem less frequently. Timur, G., M. Timur, I.I. Turna, A. Kubilay and R. Ikiz (1996) report the highest growth rate, cocoon number and fecundity for T. tubifex in still water in a substratum containing 75% fresh cow manure and 25% garden soil. It now seems that this substratum is closely approximated in more Montana streams than I thought possible!