Progress Report of 03 OCT 1996

Note- The actual slide show talk was somewhat abbreviated from this text due to a late start. Most paragraphs corresponded to one slide- there were too many slides to include them here.

This will be simple progress report emphasizing what may be the most useful of the preliminary results. Because I am talking about worms and most of you probably don't normally care much about worms, I will use some slides to help keep your attention- even at the risk of loosing your appetites. My assignment, as I interpreted it, was to master oligochaete identification, conduct a state wide survey of all species emphasizing Tubifex tubifex, map their distributions, learn their life history and basic ecology, and be ready to immediately respond to the needs of whirling disease research in Montana whatever they might be.

I must thank Dick Vincent and the Montana Department of Fish Wildlife and Parks for supporting this project and for getting it started despite my initial reluctance. I was not really certain that the project was feasible and I normally only like to take-on feasible projects. I have been working on insects, crustaceans, mollusks and leeches for a long time -- doing pretty much what now needs to be done for oligochaetes. Leeches by the way are now looking to be nothing more that specialized oligochaetes so eventually all 3 class of leeches will be reclassified as several more oligochaete families. I have taught the oligochaete families, but my early attempts at species identifications were not very satisfying. Let me just say here that the project is feasible and it is moving along fairly well. I will start with a quick review of my methods.

My approach, so far, has been simple- sample as many different waters as possible and then design additional samples to address the questions as they arise. I keep my field gear very simple so that it can be used under very different conditions and it can be easily cleaned and disinfected between samples. Note the 2 buckets with the coarse sieve in the upper one. I have tried many different field sampling techniques and I have many that now produce good qualitative worm samples from all types of shallow water habitats- I will try working on deep water habitats this winter. I am not very happy with any quantitative methods that I have tried. Worm experts report the same problems here, but fortunately, whirling disease seems to be a qualitative problem. The identity of the worms is important, the actual numbers seem to be much less important. Still when projects become more focused, more quantitative samples will be needed. These will likely be so small that they do not well characterize the site, by themselves.

Worms are very clumped so a good inventory of a site requires a large composite sample. I have done many quantitative composite sediment samples by volume. I have also tried cores and Surber samples, but I get the most worms in the best condition by doing a more qualitative composite sample using a big insect net and a small shovel. The shovel is used more to blast water to erode the sediment than to dig in it.

Regardless of the type of sample, all samples are field separated using the double buckets filled with water. The sample is added and then the upper bucket worked up and down to let the finer material fall through the sieve. Live organisms normally help themselves through when ever possible.

The contents of the lower bucket are then poured through the clean aquarium net and now gently sieved while partially submerged in the water. Heavy debris are kept in the lower bucket, which is rinsed with additional water until it is clear that there are no organisms in it. This splits the original sample into 4 parts- large debris, heavy debris, fine material that passed through the aquarium net and that retained in the net. I take notes on the contents of the coarse and heavy debris before discarding them.

The sample is first poisoned with dilute alcohol for several minutes so that the worms lay dead like limp noodles instead wrapped up in tight coils. At this point they are preserved with 10% formalin.

I keep the sample in formalin for at least 48 hours to be sure there is no risk of contamination from my lab. I next split the sample into 3 size fractions by gentle under-water sieving. Note that now the worms are long and stiff so the large ones are easily separated from the debris. I think this "double sieving" trick can be adapted to rapid sampling methods once worm size is known and can be limited.

For quantitative samples, I count the number of worms in each of the 3 size fractions or estimate that number by counting those in a known fraction of the total volume. It is fairy common to find several thousand oligochaetes in 1 litter of sediment. For qualitative samples I judge the oligochaete density as low, medium or high based on how easily I can find enough worms for slide mounting, about 100 at this point.

I have experimented with various stains, but these have interfered with getting good optical sections under the microscope. I now use no stain and sort with a dark background. Properly preserved worms are quite white and show up well under bright light.

Unlike almost everything else that I work on, species-level identification is not possible under the dissection microscope. Even the families and some inanimate objects can be mistaken with low magnification. To make permanent slides, I dehydrate the specimens, or a fraction of them, by passing them from 70% to 100% alcohol. Picking a subset of worms from a big sample to slide mount is a big problem. A simple random sub-sample will miss the rare species and include far too many immature specimens. I try to mount mostly mature worms but cover all sizes and shapes of worms, while trying to keep numbers at least roughly proportional to the raw sample. Not knowing what they really helps here.

The worms are cleared in xylene for 0.5 to 2 hours and then they are cemented in a semi-orderly arrangement onto microscope slides. The anterior end faces left, except for rare mistakes and chance movements under the coverslip. I limit the arrangement of the worms to a few sets- big worms can go on in numbers of 1 to 4 depending on size. Shorter worms can go on in 2 columns of 2, 3 or 4 each. Trying to jam more worms on a slide makes it too hard to account for them all latter.

I label the slides with the locality, date, collector and the sample and slide numbers. Labels are generated from the data file by a program I wrote. Some slides are whole worms while others have only the first 15 or so segments mounted. The latter approach gets more worms identified more quickly. Most sites have more than one species and the ratio of the species may serve as environmental indicators. To detect less common species and get useful precision on ratios, many worms must be identified.

The slides are staking up, even with my part time status on the project. I now have 9041 worms on 1640 slides from 209 samples fully processed.

I have a new compound scope on my desk thanks to help from Ernie Vyse. This has greatly speeded up identifications and removed the stresses associated with using a very old scope that was not too well suited for whole mounted worms.

When scoring a slide I move in the same order from worm to worm making a code list for the worms. The last set of slides I identified took only about 14 seconds per worm. This example represents 2 slides with 2 columns of 4 worms with some of my codes. Not all worms can be identified. Some are too young, some are damaged, other might just be mounted in a bad angle. Dealing with the unidentifiable worms is another big problem with working with worms.

The slide counts are transferred immediately to data sheets where the sample totals are made. Here are 2 examples.

I recently had a good number of my species identifications checked by Ralph Brinkhurst. I was already confident that I have good species recognition- ecology cannot make sense if your species recognition is poor, but I was not so sure of name application. This also was very good and perfect with regards to Tubifex.

All of my results are available on the WWW under my World Wide Whirling Worm Web (WWWWW) page. I am currently the only scientist posting all of their whirling disease results. My philosophy here is that whirling disease is such a serious, multidisciplinary problem that it requires maximum and rapid communication if solutions to be found quickly. I should point out that the WWW has proven to be a very good way of organizing my own work regardless of its use to others.

As I said at the beginning, the basic oligochaete inventory is already fairly well along, at least for the common species. I normally judge basic inventory progress by how surprising the samples are. When I can successfully predict what I am going to find before I process the sample- I feel pretty good that the basic distribution and ecology are well understood. This is already the case for the most common oligochaete species, and that does includes Tubifex.

Lets turn to the worms- As is so often the case when I take up a new taxon, I was at once impressed with how abundant they are and how important they must be, even though I successfully ignored them beyond the family level up until this project. Montana has oligochaetes from at least 6 families with about 65 species probable here. My Aquatic invertebrates of Montana (AIM) project is covering about 2000 species, if I added the oligochaetes it is still about 2000 species. I am well familiar with the species of several insect genera in Montana that have more species than the total oligochaete list.

The Megadrile worms or earthworms are very common in Montana waters. These are thick bodied worms with thick cuticles that do not do well in water unless it is cold and high in oxygen. We have many such streams here. There are several species frequently found in water here. Brinkhurst covers only 2 common aquatic species. For now, I am accumulating specimens and hope to get them identified latter.

The family Enchytraeidae also seems much better represented in Montana waters than reported in other areas. They too like cold water in mountain streams. These are usually easily separated from tubificids when alive as they are white instead of red and they are much stiffer. When preserved they are quite similar to tubificids until slide mounted where the chaetae are quite different. This is another family where there is little hope for quick species identifications. I am not really sure if these are enchytraeids, but they will pass for them here. The number of species in the state is unknown, but could be fairly large.

We have about 5 species of lumbiculids, but some new species are possible here. Some of these might reach well over 100 mm long even when excluding the very long proboscis.

The single North American species of the rare Haplotaxis is now known in Montana. This is a very long worm that is found in ground water and most commonly collected in springs seeps.

We have about 30 species very interesting small naids such as the predacious Chaetogaster. These are more distinctive than tubificids despite their small size. All of the non-tubificid families are getting little attention for now, but I hope to work them more latter- We never known what the next important parasite host might be.

There should be about 28 species of tubificids in Montana. The first pass WWW page for each species includes the literature results. The second pass will include my own results, pictures and maps. I have so far added only one species to my original hypothetical list. This was a west coast species that I did not expect so far inland.

The Tubificids are in comparison medium sized and more uniform in their superficial appearance. Tubifex tubifex like most tubificids is varied in size, but can be fairly large. Also like many tubificids only mature specimens can be identified to species.

Some species, including T. tubifex, are prone to ball-up when removed from the substrate. This can be a good way to separate living worms from the substrate, but even the ball may contained mixed species.

This is the latest Tubifex map from my web site. It is a pessimistic view in that red covers yellow covers green covers white. (positive-possible-negative-unprocessed). Now for the best new that I have- T. tubifex is not nearly the ubiquitous species that many people seem to think, especially in Montana. We have many areas where the species is not found. These include most of our mountain forest streams and even some of our large rivers. If the hypothesis of Tubifex as the only worm host is correct, I can assure you that most of our headwater populations, including the remnant cutthroat and bull trout will be quite safe. Now for more good news. The occurrence of Tubifex in Montana trout streams is nearly always clearly caused by human actions. This might sound sad, or even despicable, but I consider it good news because if we caused it we can correct it. I should point out here that I could have many more green dots here- the conditions where Tubifex is found in Montana is already so clear, that I am not taking too many samples in obviously negative areas.

On the WWW, this map is linked to a program so that it provides the details of the samples from any location that you click on. This makes new data easily available. Note the seasonal variation in the 2 samples from this site- we will get to that soon, but first we need to take a good look Tubifex tubifex.

It is most important to recognize Tubifex tubifex for what it is- a tramp, even a super-tramp. These are nothing more than the animal equivalence of a weed, and as such they are characterized by 3 outstanding biological features. First is a tremendously wide environmental tolerance. You may think of T. tubifex as pollution tolerant, but that is not too useful in Montana- just think of it as broadly tolerant. Second is an almost supernatural power of dispersal. With T. tubifex this is well documented, but the details are not well known. The young worms can encyst and the cocoons are quite tough. We need not worry about introducing Tubifex- if conditions are right it will be there. So tramps and weeds are broadly tolerant and widely dispersing- why aren't they everywhere? The price they pay is the third outstanding biological feature. They have an almost pitiful ability to deal with the normal interactions, competition and predation that occur in normal, diverse communities. So with a weed, if you clear away the native vegetation from a piece of ground- and it doesn't much matter what the native vegetation was or what the ground is like, the same damn weeds appear almost overnight, but they do invade nearby diverse communities. Tubifex is the same- simplify the native benthic community and it will come. If the bacterial food source is rich they will be abundant and fast growing, and if the food source is poor they will be less abundant and more slow growing.

Diversity reduction can be due to dams, These can be very good for Tubifex because the food is rich and the abnormal flow and temperature greatly reduce the number of insects species that would normally dominate.

Diversity reduction can also be caused by dewatering for irrigation and the runoff of agricultural chemicals. Tubifex likes pesticides.

Diversity reduction can also be caused by livestock grazing and their waste.

Diversity reduction can also be caused by canals and their associated activities. Canals currently hold the Tubifex density record which can be so high as to color the bottom red. In this dry canal, if you want Tubifex, just add cool water.

Diversity reduction can also be caused by Human waste. Montana water law says that a hole in the cobble and boulders near a stream does not make a well- someone should add that it does not make a septic system either. The only place I have been able to find Tubifex in the Big Hole River is associated with such seepage areas.

Diversity reduction can also be caused by sedimentation- I need to be careful here because it gets complex and there is much confusion.

Tubifex tubifex does not need fine sediment. I have found Tubifex in clean sand, gravel and cobble, and even on boulders where the worms live right in the gooey slime on the rocks in the absent of fine sediments. They can even form tubes from their own feces if there is no other material present.

I have also found Tubifex on almost bare concrete in canals and fish hatcheries. The worms can be both large and abundant with only a couple millimeters of crud covering the surface. It is quite clear that the physical habitat cannot well predict T. tubifex presence.

What T. tubifex needs is a simplified community and sedimentation will do this. There are few species in the rocky Mountains adapted to occupy the extensive mud flats that can develop due to excessive sediment loading. I should also point out that we have many areas with extensive areas of fine sediment that are totally without T. Tubifex.

Tubifex is so broadly tolerant of the physical environment that there really is not any such thing as Tubifex physical habitat. However, I think I have found limiting physical factor- T. tubifex appears to be a cold water species and is not present in warm water, at least during the warm season. I have found probable Tubifex in the shallow water of a single lake- the coldest one I have visited. The literature has T. tubifex as a northern species and in lakes normally only in deeper water. In warmer trout streams T. tubifex takes on a long winter life cycle like many of our insects. The young worms appear in the fall, grow through the winter and mature and reproduce in the spring. The adults normally die after reproducing and disappear with spring runoff. Cooler streams have no such pattern even with large spring floods.

Lets review some of these findings by looking quickly at the Madison River Story- Above Hebgen I have not yet seen a single positive T. tubifex in many samples, but there are worms that could be Tubifex, and I would not be too surprised to find it there- The Madison River even above Hebgen is not that diverse due to abnormal temperature and chemicals from Yellowstone National Park. New Zealand Mud snails may reduce that diversity further- or maybe they eat Tubifex? Between Hebgen and Quake Lakes Tubifex is very abundant- Curiously, several areas like this that are very cold throughout the year and have abundant trout and Tubifex as well as heavy bird and fisherperson traffic, do not seem to get the disease- I hypothesize that the parasite itself has a temperature limitation, the details of which need to be known. Below Quake Lake Tubifex becomes very rare although oligochaetes are abundant. Tubifex quickly increases downstream toward Ennis Lake. From Noris bridge to Three Forks Tubifex becomes rare and takes on the winter life cycle. I Hypothesis that the disease will fizzle out as it moves downstream with some annual variation probable depending on flow and temperature.

I will cover the Blue Ribbon Missouri River Story a little more slowly. Starting at Cannon Ferry Dam, Tubifex becomes abundant even in rough clean cobble.

This continues below Holter dam, but Tubifex largely disappears by Ulm Bridge, about the end of the trout zone.

As for the spawning streams- lets start with Sheep Creek. A late summer sample from this small stream took 38 non-worm taxa. This is a remarkable number and it included many very interesting finds. I would be quite happy doing additional work on this stream. Any guesses on Tubifex? -- None present is the correct answer- Bravo Ernie Vyse. This stream should continue to provide good spawning and safe early rearing.

Lets move over to the Dearborn River. This beautiful river comes straight off the front of the rocky mountains and has very large spring floods. The substrate sizes are mostly boulders with essentially no fine sediment present. Any guesses on Tubifex here? -- I am asked about the community there- Bravo again Ernie Vyse- I tried to sucker you- I did not give you any useful information to base your guess on and I tried to play on your old Tubifex biases to get the wrong answer. Tubifex was there. This was only a little surprising to me- I normally skip the Dearborn River because I never get anything good there. Now that is a more useful clue.

Looking at a composite map I think tells the rest of the story. The irrigation canals and the abnormal, late-season green vegetation in the lower elevations indicates considerable agriculture throughout the drainage. There is probably no safe rearing areas here.

Now for Little Prickly Pear Creek itself. The situation here has some interesting twists. I had already sampled the steam near the mouth and found only a few Tubifex. I figured these rapidly declined to zero moving upstream- wrong! Here we have a mountain stream with 2 large flats in the middle of the drainage.

The Chevallier range complex.

and the Seiben ranch area.

Both have considerable agriculture and irrigation impacts.

and they frequently convert the stream into a Tubifex filled mudhole.

However starting just below Seiben area the stream enters a narrow canyon with the interstate and the railroad and the frontage road. The stream is straightened and narrowed leaving little room for sediment deposits. Here the normal community recovers somewhat and Tubifex becomes rather rare until very near the mouth again.

Two important spawning streams, Lyons Creek and Wolf Creek appear to be free of Tubifex.

I took a single worm that could be Tubifex from Lyons Creek, but that was very near the mouth. I should also addd that Wolf Creek had a high density of oligochaetes, but still no Tubifex. So lets look at the drainage again and consider some options. We need an adaptive approach to be able to quickly respond to what we find. I proposed a fish barrier between Lyons Creek and Seiben Flats as soon as the picture here was clear to me. We do not need spore loaded spawning fish dying in the worm filled mud holes of the middle drainage. If we are really lucky, and I do not feel lucky- we might keep the disease out of the upper drainage entirely. But if it gets there and if it becomes an important TAM factory, we might try modifying the stream near the fish barrier to form a shallow water, high gradient flume for some distance. This section of the stream has several thousand filter feeding insects per square foot of solid substrate- I would like to see if the TAMs can get trough this biological filter. We can also clear fish barriers from the worm free tributaries and protect them further. We might also need to habitat management to remove worm hot-spots that occur in the canyon area. We might consider restricting spawning Brown Trout for the stream altogether with a seasonal fish barrier at the mouth. If all else fails I do have a plan B with I am quite sure will get Tubifex out of the drainage entirely, but this will require major land and water use changes in the middle drainage.

So if we treat whirling disease as an environmental problem rather than a fish health problem we have many reasons for hope. I should point out that parasite outbreaks are often due to environmental changes. Abnormal host populations or range shifts are often the problem and reversing them is the easiest cure. Treated as an environmental problem we also already know how to fix it and we can be sure that it will work. The story on Tubifex in Europe and Eastern North America is quite clear- degrade the streams and Tubifex appears, clean them up and Tubifex disappears. We may not known how best to do this, but we can do it. We may lack the resolve, or the courage, or the clout, or the money, but we known how to do it. Doing the right thing here is also totally in line with modern soil and water conservation practices that are occurring in more developed countries and states. So in opening that can of worms (so to speak), I will stop for discussion.

sunset over river

03 OCT 1996, D.L. Gustafson
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