Aquatic Invertebrates of Montana

Montana Tubifex Summary

A golf ball size ball of Tubifex tubifex. When removed from the substrate the worms may "hug" each other to form a semi-solid ball. These came from the lower Gallatin River.

Lead Topics

• Tubifex likes it cold!
• Some misconceptions about Tubifex tubifex

Point Summary

• Tubifex tubifex Muller is still the only known intermediate host for salmonid whirling disease, as far as I know. I suspect that it will prove to be the only worm host, at least in our area. Undoubtedly, many worm species and other detritus eating species will ingest the spores, so finding the genitic marker for the parasite in other species is of little value, by itself. The big question is what happens to the spores when ingested by various species- are they digested, passed, or activated? and then is the development complete or incomplete?

   

• Tubifex tubifex is not an easy species to recognize with certainty. It lacks the more distinguishing characters of other species, which means that immature specimens or pooly preserved or badly mounted specimens may be easily mistaken for it.

   

• Tubifex tubifex is a world-wide species that is not much limited by the normal barriers faced by other aquatic organisms. Like many microbes, it pretty much occurs where ever suitable conditions are found. It clearly has the potential to occur anywhere in Montana. It is not, however ubiquitous, especially in Montana. We have many streams that lack suitable conditions for it. The introduction of T. tubifex by itself, should not be a major concern- if conditions are suitable for it, it will already be there.

   

• The Key habitat needs of Tubifex tubifex appear to be biological, not environmental. It needs bacteria as a food source and a general lack of competitors and predators. Water and substrate conditions seem irrelevant to it. It can live in thin or thick mud, sand, gravel or even on bolders and other solid substrates. In the latter case, such as the concrete raceways of fish hatcheries or on the boulders in rapid rivers, the worms seem to be limited to the biofilm formed by bacteria and algal growths aided by the deposition of the worms fecal material. It can live in running or standing water and it ranges from cold mountain seeps to warm prairie rivers. Few other aquatic species span such a wide spectrum of physical conditions.

   

• Tubifex tubifex is a species of depauperate communities, especially those that are depauperate of insect species. Tubifex tubifex often occurs nearly alone, but with large populations. It is usually associated only with other tubificids, leeches, mollusks, planarians, hydras, isopod and amphipod crustaceans, and among the insects only some dipterans (Chironomidae, Ceratopogonidae, Tabanidae and Tipulidae).

   

• Tubificids in general and Tubifex tubifex in particular are not very common in our cold, high gradient streams that have their normal diverse insect communities intact. Other tubificid genera and other oligochaete families are more common in these streams. This may offer hope for disease-free headwater areas, which may protect our native species and allow some safe rearing areas. Even some of our large rivers, such as the Yellowstone River above Livingston and the Gallatin River above the East Gallatin River, are still quite free of Tubifex tubifex.

   

• The depauperate invertebrate communities prone to Tubifex tubifex domination occur in some springs and spring creeks, the transition zone between the mountain and the prairie communities, and in degraded habitats such as below dams, in irrigation canals, and in areas generally affected by pesticides, sedimentation, nutrient and organic enrichment or any other factor that lowers the normal community diversity. This appears to be the case in most of our known whirling disease sites as well as others such as the Big Horn River, the Musselshell River, the East Gallatin River including even Bridger Creek, the Gallatin River below the East Gallatin River and the upper Missouri River.

   

• The hypothesis of additional invertebrate hosts for whirling disease may be correct, but it is not necessary to explain the distribution of the disease in Montana. Tubifex tubifex appears to be common in areas affected by the disease as well as additional areas that are not yet affected. However, some of the areas the are not yet affected are essentially free of Tubifex tubifex and presumably will not be affected even if the disease organism is introduced.