Archives of the Twelfth Headwaters Conference, November 2-4, 2001
Conservation of the Exotic: Fishes of the Upper Gunnison Basin
A paper prepared for the 12th Headwaters Conference, by Kevin D. Alexander, Ph.D.
Introduction
When I moved to Gunnison about a year and a half ago, I began to explore the aquatic environment of my new "place" by working on a list of fishes that could help with some of the courses that I teach here at the college. During the compilation of the list of fishes and associated biological information, I began to realize that the way we address the fisheries of this basin tells us much about the way we view where we live, and the non-human world there.
The area that I will cover in this paper is confined to what I will call the upper Gunnison River basin which includes all of the streams that feed the Gunnison River above the Gunnison Tunnel which was a tunnel built in 1910 to divert water from the Gunnison River to the Uncompagre Valley for irrigation. This is not just an arbitrary point but roughly corresponds to a division of "coldwater" or "headwaters" fishes (Behnke, 1993) from warmwater fishes. Plus, it keeps this paper much simpler.
Fishes of the Gunnison River Headwaters Zone
The list that I have compiled of fishes currently found in this "headwaters" zone of the Gunnison River is:
Family Salmonidae – trout family
- Lake Trout
- Brook Trout
- Brown Trout
- Sockeye Salmon
- Cutthroat Trout
- Colorado River
- Snake River
- Yellowstone
- Golden Trout
Family Esocidae – pike family
- Northern Pike
Family Cyprinidae – minnow family
- Rio Grande Chub
- Speckled Dace
- Longnose Dace
- Fathead Minnow
Family Catostomidae – sucker family
- White Sucker
- Flannelmouth Sucker
- Longnose Sucker
- Bluehead Sucker
Family Gasterosteidae – stickleback family
- Brook Stickleback
Family Percidae – perch family
- Yellow Perch
This totals to 17 "distinct species" found here, but you can throw in other measures of diversity such as unique genetic strains. So if you add the three subspecies of trout the number goes higher. In addition, you can start considering hybrids such as those between the rainbow trout and the cutthroat trout or the "Pike's peak cutthroat" which is a hybrid of Yellowstone and greenback Cutthroat trout. When all of the subspecies are considered the diversity approaches 22+ "flavors" of fish. That's quite a respectable number for a typical headwaters area in the Rocky Mountains but it is a mere fraction of the 200+ species that can found in tributaries of the Mississippi.
I do not feel that the current list tells the complete story of the diversity of this basin. When the historical records of fishes in this basin are viewed, such as those from early ichthyologists like the eminent David Starr Jordan (1891), and then you look at the records of fish introductions compiled by the Colorado Division of Wildlife, a much more complete picture of the fish diversity emerges. I realized that there are really only four species of trout native to the "headwaters" zone of the Gunnison River -- those that arrived here by the power of their own fins. Those species are:
Family Salmonidae – trout family
- Colorado River Cutthroat Trout
Family Cyprinidae – minnow family
- Speckled Dace
Family Catostomidae – sucker family
- Bluehead Sucker
- Flannelmouth Sucker
Of the four native fishes, I can only commonly find relatively abundant populations of speckled dace. The Gunnison River strain of the Colorado River cutthroat trout (CRCT) has only about two remaining populations. These strains are important because they are unique from a genetic and evolutionary standpoint. Each population of CRCT is confined to water that remains relatively cool for the entire year. If a CRCT from the Gunnison River were to mate and transfer genes to another CRCT in the Wasatch Range of Utah it would have to travel through hundreds of miles of river that would be lethal. This has kept strains in different river basins on separate evolutionary paths. So much so that they can have genes that are up to 35% different from one basin to the next. Compare that to humans who may only differ by 5% across all of the continents.
The most drastic changes has been with the two sucker species that are no longer found in the upper basin and can be considered to be locally extirpated. So to go from four species to 22+ "flavors," many hidden changes occurred in the basin that have led to the loss of 50% of our native species and the severe reduction of an additional 25% of the native species. The factors responsible for those changes can be summarized under a few categories: non-native fish introductions, conservation related issues and habitat alteration.
Non-native fish Introductions
Documented trout introductions began with the brook trout native to the eastern U.S. in 1883, the rainbow trout native to the Pacific Northwestern U.S. in 1888, and the brown trout native to Eurasia in 1893. The globalization of the fishes of the Upper Gunnison Basin had occurred well over a century ago.
These species are responsible to a large degree for severe decline of the native strain CRCT. The rainbow trout hybridize readily with CRCT and alter the genetic makeup. The brook trout primarily compete for food and space with CRCT especially in smaller tributary streams. Brown trout, being strongly piscivorous, feed heavily on fry of other species such as CRCT.
Additionally, the CRCT numbers were probably severely reduced due to overexploitation by fishing pressures by early settlers, miners and market fishermen. CRCTs are considered to have high catchability (citation) so that they are easy to catch even by fishermen with little skill such as myself. Records also indicate that they grew to be very large in the area. For example, newspaper records show a 12 pound, three ounce cutthroat trout being caught on the Gunnison River at the mouth of Cebolla Creek. Competition with introduced species, high fishing pressures, high catchability, large size and the lack of fish protection laws led to a precipitous decline in CRCT numbers and to their near extinction in this basin today.
Many other species were inadvertently introduced when stocking trucks brought in "game" fish to be stocked. For example, white suckers were probably brought in with fishes from the hatcheries on the eastern slope of Colorado. These began to compete with the two native sucker species and were especially able to compete in areas that were altered by the construction of dams. White suckers are also able to hybridize with native sucker species. The white sucker "problem" led to the introduction of northern pike into Taylor Reservoir around 1937 as a means of controlling the sucker population. The pike population is probably the highest population of northern pike in the world (Behnke, 1993).
Other species have been released through what is typically called "bait bucket release." This is when at the end of the fishing day an angler has unused bait-fish that are released into the water when the fisherman dumps a bait bucket. It is presumed that the brook stickleback was introduced in that way because they are commonly found intermixed with minnows sold at live bait shops.
The yellow perch is suspected of being a clandestine introduction into Blue Mesa Reservoir. Some anglers have affinities for certain species that they have caught elsewhere. They then want the opportunity to fish for them where they currently live and will deliberately introduce them into a new area. That is how yellow perch are rumored to have made it into this region, and there have been additional rumors of attempts with smallmouth bass and walleye.
Historical Conservation Issues
Even with the disappearance of CRCTs quickly after European settlement in this valley, the Gunnison River continued to produce large and numerous exotic trout illustrating how productive this fishery was. A photo taken in 1895 shows three anglers who caught nine rainbows ranging from 5.5 to 9 lbs. in a reported three hours of fishing near the mouth of Tomichi Creek. Reports like this gave Gunnison a national reputation, with people traveling here by train just to fish in these waters. Fishing resorts sprang up in places like Iola and Sapinero while trainstops such as the one at Cimarron would serve Gunnison River trout.
This reputation earned the Gunnison River the title of "world's best trout stream" by the National Geographic Society right after the turn of the last century. This occurred even though the native fish had essentially been removed by this time and replaced with non-native fishes. The reputation coupled with the high fishing pressure and lax conservation laws removed tremendous numbers of fish from the river and caused the size and number of fish to decline (Wiltzius, 1978).
Habitat Alteration
The tremendous productivity and world-class reputation of the Gunnison River began to change with the influence of agriculture in the basin. Along tributaries that were the predominant spawning areas for trout, cattle grazing eliminated riparian vegetation and eroded banks, causing the preferred spawning beds to silt in. Dewatering for irrigation reduced water flow and increased tributary water temperature due to the shallowness of the streams. Reports for the DOW who would catch spawning trout for hatchery stock reported that virtually no trout were spawning in tributaries by the 1930s. Nearly all trout spawning had switched to mainstem spawning that decreased reproductive success. By the 1950's and 1960's most trout caught from the Gunnison River were of hatchery origin, and angler catch was directly dependent upon stocking rather than "wild" reproduction (Wiltzius, 1978).
Due to this habitat alteration, the trout reproduction and production plummeted. This would have probably occurred regardless of which trout species were present and the Gunnison basin CRCT would have suffered a decline in reproduction and growth as the exotic trout present underwent.
Oddly enough, an exception is that one of the Gunnison basin CRCT populations exists in a stream that no longer connects to the Gunnison River. That stream had been dewatered for agriculture presumably early enough that the exotic species could not invade that tributary, thus leaving that population of Gunnison Basin CRCT protected from competition and genetic pollution from the introduced trout. In a sense, habitat alteration preserved one population of the native species.
Modern Result
I was talking to a family who had been fishing on the upper Cochetopa every year for the last twenty years. He knew I was an aquatic biologist and professor at the college so he made a point of telling me that he kept all of the cutthroats but made sure he released all of the "wild" brookies (i.e., brook trout) in order to keep their population abundant. It made me grin from ear to ear because neither fish is native, including the cutthroats, which are an introduced subspecies, but it also made me come to some realization about the way we understand our sense of place.
I realized that few of us have an understanding of what the Gunnison River is or was. In a sense, the Gunnison River currently has little that makes it unique because one can go to many places in the U.S. and catch or observe the exact same fishes.
This loss of historical context and uniqueness makes aquatic conservation here a unique challenge because none of us have any "experience" with the way this area was historically. This makes it difficult to deal with a public that has a minimal concept of the native history of this river system. How do you develop a "conservation" ethic that includes native fauna, in a place where no one has a sense of what it was originally? This is particularly relevant with widespread development of a conservation ethic for game species protected as a resource.
The result is a conservation ethic applied to an exotic fauna. We now have a "catch and release" fishery on the Taylor River that gives one of the highest levels of protection to a ichthyofauna composed entirely of introduced fishes. This river is famous for its huge rainbow trout that must be immediately returned to the river unharmed if they are caught.
We also get state designated "wild trout waters" such as the East River near the Roaring Judy fish hatchery where fish are no longer stocked. These fish -- none of them native -- are considered "wild" and supposedly give a feel to the angler similar to a historical fishery. In these waters, you can only use flies or artificial lures to increase the challenge. Anglers are also limited to keep very few, larger fish.
Many anglers only use barbless hooks to minimize harm to these fish and many purists use only artificial flies as lures. Purist anglers are often aghast at others who would sink so low as to use a spinning lure or baits because their ethic considers that to be "unsportsman-like."
These actions, I feel, are from people who have wonderful conservation ethics but my have little understanding of the history of this basin, and a sense of place that is limited to only a modern understanding of the fish fauna. These actions would be equivalent to protecting the Kentucky Blue Grass (another exotic from the eastern U.S.) that grows on the lawn of campus, with people demanding that we cease mowing it or walking across the lawns to minimize harm. Likewise, we could have "wild cow" regions in our public lands where elk and deer no longer roam but the cattle were protected from the hunter and dinner table.
Also involved is the introduction of exotic diseases such as whirling disease which evolved with brown trout in Eurasia but is debilitating to trout such as rainbows, brookies and CRCTs that don't have an evolutionary history of developed resistance. This is similar to the smallpox epidemic among the native peoples of North America after the encounters with Europeans. Whirling disease has decreased rainbow trout numbers in the Gunnison River and the conservation ethic has been to suspend any removal of rainbow trout from the river.
Meffe (1992) also argues that we have become dependent on "halfway technologies" in modern fish management. He defines a "halfway technology" as one that treats a symptom rather than the cause of the problem. He claims that hatcheries do not solve the problem of decreased fish numbers but just supply fish to the system without solving the root cause of the low fish numbers.
He makes a rather lengthy argument that, due to the hatcheries' high energy and labor inputs, they are not sustainable and counters that harvesting of fish above their populations' ability to reproduce, coupled with habitat destruction and alteration, are the true causes of fish decline. Our approach of supplementing fish numbers with hatchery stock is equivalent to just continuing blood transfusions to a person bleeding to death rather than stopping the bleeding. I hold to the motto that, if you want to get out of a hole, you have to stop digging.
If we are to solve some of these problems, we need to deal with the causes of poor habitat and low reproduction rather than just treating symptoms by putting more put-and-take fish into the river. We have to stop degrading riverine systems and keep fishing pressures lower if we are to really start solving these problems.
Meffe (1992) also states that hatcheries have the compounding effect of making the public feel that rivers are healthy because they simply have fish in them. For example, the average life expectancy of a trout on many Colorado eastern slope streams is less than a couple of weeks but most people consider these rivers to be pristine because they are harboring large numbers of trout. They do not realize they were fresh from the hatchery and are not a sign of a river where fish abundantly complete their life cycles.
Future
I am not naïve enough to presume that we will or should restore a totally native fishery to the upper Gunnison River basin. I do, however, advocate at least a partial restoration to a fishery composed of native fishes like the Gunnison River strain of CRCT so that what made the Gunnison River unique and "the world's best trout stream" can still exist. To achieve this end I think we must begin by developing a sense of place that contains some historical realities. We must start understanding the fishes that presently live in our rivers are essentially "wild cows" -- trout of hatchery origin that have been imported from elsewhere. We must also realize that fish stocking is not a permanent solution to low numbers of fish or the restoration of health to our rivers.
To implement even a partial restoration, we first must put a priority on preserving the few native populations of CRCT in this basin. We can begin to utilize our hatchery technologies to rear native fishes to help them return to their native streams. This utilizes pre-existing facilities and technologies, but it allows us to reach a sustainable end rather than them acting as "halfway technologies."
Assisting the native CRCT by removing competitors will be important. I know of anglers that have conservation ethics that they apply to the historical fisheries by living by a moral obligation to "remove and kill any non-native fish." This would require a change in current DOW regulations, making it mandatory to keep any brook, brown or rainbow trout caught. That would have to be coupled with the regulation that we currently have in place for the exotic rainbow trout, of returning any CRCT immediately to the river unharmed. After the native fishes return to sustainable numbers we could then revise the fishing regulations.
These activities would reverse a century old trend of systematically reducing to near extinction the fishes that made the Gunnison River unique in all the world. It would take a paradigm shift in our knowledge of place and our value system. However, it could be done, and the DOW has begun some steps to enter this path. They will need some help and persuasion from the public for this to proceed.
Acknowledgements
Dan Brauch, Colorado Division of Wildlife and Art Hayes, U.S. Bureau of Land Management, provided valuable background and support information. Curt Gravis, Pete Gauss, Robin Bingham, Jessica Young and George Sibley, Western State College and Shann Stringer, New Mexico Environmental Department through discussions helped me develop many of these ideas. Students in my fish biology seminar endured a painful first draft of this presentation and their questions and comments greatly improved it. The errors, omission, weakness in thought and poor writing are my own responsibility.
Literature Cited
Behnke, 1993. The Gunnison River drainage and its changing fish fauna. Unpublished paper.
Jordan, D.S. 1891. Report of explorations in Colorado and Utah during the summer of 1889, with an account of the fishes found in each of the river basins examined. Bull. U.S. Fish Comm. 9: 1-40.
Meffe, G.K. 1992. Techno-arrogance and halfway technologies: Salmon hatcheries on the Pacific coast of North America. Conservation Biology 6(3):350-354.
Wiltzius, W.J. 1978. Some factors historically affecting the distribution and abundance of fishes of the Gunnison River. Final Rep. To Bur. Sec., Fishery Investigations of the lower Gunnison River drainage. Colo. Div. Wildlife.
Wiltzius, W.J. 1985. Fish culture and stocking in Colorado, 1872-1978. Colo. Div. Wildlife. Rep. 12.