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.
- 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
- 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.
17 MAR 1996, Updated on 27 AUG 1996 D.L. Gustafson
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