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 (Dean Hendrickson) |
General information: (E. Phil Pister) |
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To ensure the long term survival of Rio Grande sucker as part of the aquatic wildlife community in waters of the San Luis Valley. The conceptual idea is to protect the genetic purity and preserve the genetic variability of remaining stocks this fish.
Create at least three stable metapopulations of Rio Grande sucker: one for each of the river basins of the San Luis Valley that include the Closed Basin, Rio Grande and Conejos drainages. Ancillary to this work it would be desirable to also manage a number of refugia that include populations that must be maintained by intensive management in isolated streams and perhaps other waters. A key feature of the early stages of the recovery effort will be research to better understand life history and also population and community ecology.
1. Create a database of waters that have Rio Grande sucker or reestablishment potential. It is necessary to prepare maps and reports listing waters with Rio Grande sucker. The resource management agencies currently use several databases that include attribute systems and spatial mapping systems. These include paper file archives, dBase translations of these files, GIS, ARC-INFO and ADAMAS within the DOW (Jones, pers. comm.) and IRI/CWU. The data and records will be available for use by other agencies, organizations and individuals involved in resource management decisions.
A. Research is needed to better understand the characteristics of optimum Rio Grande sucker populations and their habitat. It is essential to identify the limiting biotic and abiotic factors. With this information it will be possible to develop criteria to select waters for additional surveys.
B. Inventory of individual waters and watersheds should start with a background check of the physical and biological characters that comprise the preferred habitat selection criteria. One intriguing aspect would be to focus inventory on waters influenced by thermal hot springs. The background check consists of examination of U.S. Geological Survey (USGS) topographic maps, past fish stocking records and any previous field surveys.
C. Prepare lists of candidate waters for field surveys. Priority will be given to waters that appear to meet the habitat needs of Rio Grande sucker. Waters with no records of fish stocking or are thought to contain only native fishes will be considered first.
D. These surveys should minimally include a check for species richness, data describing biomass and community structure, and physical and chemical characters. Acceptable formats for these data include: standardized stream and lake survey forms used by DOW, the Basinwide Inventory used by the USFS and BLM.
E. Inventory results should be mapped using USGS topographic maps and future electronic database systems. Computerized records and maps will be available on a DOW network, perhaps in 1998. Paper records will be housed at the DOW offices in Monte Vista and Montrose.
2. Identify potential Rio Grande sucker populations. An efficient way to gain additional pure populations of Rio Grande sucker is simply to identify previously undiscovered remnant populations. The location of most populations in Colorado and New Mexico is known with a high degree of certainty. What is less known are the precise identification and differences among the populations. The taxonomic characters of Rio Grande sucker from Hot Creek were described by Zuckerman and Langlois (1990)and Smith (1966) described specimens from the mainstem Rio Grande. The morpho-meristics of the New Mexico populations are partially known. In addition, studies of the biochemical and DNA characters of Rio Grande sucker in Colorado and New Mexico are incomplete. Quantification of the characteristics of individual populations using several techniques is essential because it is a critical pathway linked to creating new Rio Grande sucker populations. This requires use of techniques ranging from standard classical taxonomy to experimental procedures that look at molecular DNA. The purpose of the identification work is to describe the genetic purity and genetic variability of potential populations. These data can be used to make decisions about the level of protection needed or the utility of various stocks in the conservation program.
A. Collect and prepare specimens for analysis. A standard museum label and collection catalog should accompany the collections. This includes fixing whole specimens in formalin, with permanent storage in denatured alcohol. Tissue prepared for mitochondrial DNA analysis can be preserved in pure ethyl alcohol or frozen on dry ice. Specimens prepared for protein electrophoresis must be kept on dry ice and stored in a very cold deep freeze.
B. Develop techniques to describe the various stocks or families of Rio Grande sucker throughout it's range. Techniques used may be standard taxonomic techniques, analysis of mitochondrial DNA, and protein electrophoresis or some combination of these.
3. Monitor existing or reestablished Rio Grande sucker populations and their habitat. Conduct periodic population and habitat surveys to identify trends in the fish community. One purpose is to collect population data such as biomass, age structure, and density. This biological information can be used to assess the viability of various stocks. Combined with physical-chemical data it should be possible to assess land management problems. Detail is outlined in section 1D.
4. Establish, maintain and manage at least three metapopulations in the Closed Basin, RioGrande and Conejos drainages. Metapopulations consist of several smaller subpopulations. These subpopulations are interconnected and fish may move among them as habitat conditions change. Thus, over the long term, the metapopulation would have greater stability and resistance to extirpation than subpopulation or refugia. At pre4sent the definition of a stable population is unclear.
5. Identify or create stream refugia using stream selection criteria. As a starting point for the creation of refugia, stream characters could be compared with preferred Rio Grande sucker habitat in Hot Creek. Two considerations might be the absence of nonnative fishes, especially white sucker, and good water quality. As correlations between Rio Grande sucker presence and habitat characters are researched, the selection criteria can be improved.
6. Transplant fish to appropriate habitats.
A. Plan fish reclamation projects and prepare the necessary environmental assessments and chemical treatment plans. Sometimes, it can be possible to restore the biological balance that will allow transplanted sucker to prosper.
B. Remove nonnative fish with piscicides following Colorado DOW Chemical Treatment Operation Procedure (1987). Registered fish eradication chemicals include rotenone, antimycin and potassium permanganate.
C. Use wild salvaged fish from donor waters determined to have adequate populations. It would be desirable to create three very productive wild metapopulation in Colorado that could, in time, serve as instate donor streams for future transplants. For example, do the Brazos, Jemez or Mimbres drainages in New Mexico contain donor populations of Rio Grande sucker suitable for transplant to Colorado? Are Rio Grande sucker from New Mexico the same as the Colorado genotype? If the modern New Mexico specimens approximate the expected characters of the historical collections from Colorado, then it may be possible to pursue transplants of Rio Grande sucker from New Mexico to streams in Colorado in the future.
There are choices for generating the data to compare New Mexico and Colorado specimens. One choice is to compare the meristics of Rio Grande sucker populations currently existing in from New Mexico to meristics specimens collected from Colorado during the 1940s. Old specimens are housed in the museum at the University of Michigan. Mike Hatch (pers. comm.) already has electrophoretic data describing the subgenus Pantosteus in New Mexico. It would be simple to compare a few gene loci from modern Hot Creek fish but difficult to do this with preserved museum specimens because of tissue degradation. Another possibility is DNA analysis to compare populations. This involves additional research to develop the analytical techniques and understand the DNA sequencing that describes Rio Grande sucker throughout its range. If the New Mexico populations are similar genetically to the Colorado populations, then reintroduction could become an important management tool.
Alternatively, if Colorado and New Mexico Rio Grande sucker are significantly dissimilar, then it may be impossible to recover the Colorado genotype. The assumption is that the original genotype representing the Colorado version of Rio Grande sucker is compromised. At this critical point, a decision would be made whether to pursue recovery by expanding the distribution of the Hot Creek or Conejos River phenotypes. The basis for these decisions lies in whether it is desirable to transplant phenotypes if that is all that remains. If the decision is made to not transplant phenotypes, then one population of Rio Grande sucker will exist in Colorado.
There are advantages to transplanting fish from wild stocks primarily because hatchery propagation problems are reduced. Disease certification, commitments of hatchery space and culturists time, hatchery accidents, and human-influenced selection are avoided. To use wild fish as transplant stock it is essential to first ensure that the fish are genetically pure. Costs of using salvaged fish to create a new sucker population are higher. Also, fewer fish are available for transplant because most wild populations of Rio Grande sucker contain few individuals, except for the Rio Mimbres. At the same time, these fish may be better adapted to surviving in the new habitat. Additional transfers could be made later to increase the genetic variation and size of reestablished populations until they are self-sustaining.
D. Develop techniques and procedures to spawn and rear genetically acceptable fish that are disease free in a hatchery environment. It is unknown how a brood fish population in a hatchery should be managed to produce genetically acceptable progeny for reintroduction into streams with restored habitat. Laboratory experiments will be needed to better understand whether artificial culture is possible and if so, to develop propagation criteria. It is important to study spawning and rearing problems that lead to genetic alteration (Mike Young, pers. comm.). Loss of genetic variation decreases the ability of a population to respond to environmental changes. Current topics for concern include deciding how many individuals to use to found a population, genetic drift in a hatchery, using unequal numbers of offspring from different parents and artificial selection in the hatchery.
Another area for research is how to reincorporate the wild genome into the brood stock. If only milt from wild males is used, then variation of the genome will decrease because mitochondrial DNA is not passed paternally. Also, it is difficult to incorporate the genetic variation found in populations of Rio Grande sucker into a broodstock. There is variation among watersheds and even within a single watershed.
E. Use hatchery propagated fish from the established wild brood stocks. The strategy for this tool is to stock many fry by produced from captive brood stocks. The fry would be held in the hatchery environment for as short a time as possible to minimize adverse genetic selection, e.g., a September plant from fish spawned in June. In this way, possible loss of wild characters that are concurrent with mass propagation would be minimized which would also help ensure survival in natural environments. Cultured fish would not be stocked into wild populations that have no history of stocking.
7. Improve physical and chemical Rio Grande sucker habitat in streams. Applied research is needed to understand the biotic and abiotic components of Rio Grande sucker habitat. Field surveys and laboratory experiments will lead to development of criteria to select streams for habitat restoration in Colorado. Habitat assessment of the individual streams will allow limiting factors to be identified.
Rio Grande sucker habitat improvements should be included in watershed management decisions made by resource management agencies and organizations, such as the USFS. Watersheds with populations of Rio Grande sucker will be identified in Forest Plans, grazing allotments, RMPs and AMPs, activity plans and integrated resource plans. They will be surveyed and site plans developed to mitigate adverse impacts to water quality, instream habitats, channel morphology, riparian areas, and the stability of the population.
A. Create or improve migration barriers at bottom of existing or potential Rio Grande sucker refugia. Barriers will be designed to insure that no upstream migration of other fish will be possible. These habitats should be considered short term refugia that have value toward creating the critical biomass needed to develop metapopulations of Rio Grande sucker.
B. Create Rio Grande sucker habitat in watersheds consisting of several tributaries that are linked by migration routes. These metapopulations would be resistant to extirpation because not all streams in the watershed are likely to suffer an environmental catastrophe simultaneously, such as a large, hot forest fire, thus some populations will remain despite habitat loss nearby. Even if some subpopulations are extirpated because of poor habitat, they could be recolonized by migrants from larger subpopulations. An essential feature of this activity is to identify and rank candidate streams for reconnection. This will require research to characterize optimum habitat. This means the eventual removal or modification of migration barriers and should be viewed as a positive sign of increasingly secure Rio Grande sucker populations.
C. Improve instream cover, pools or spawning gravel with structural improvements. Prerequisite to habitat improvements in individual waters is correction of problems caused by unfortunate watershed management.
D. Improve stream bank stability and riparian vegetation conditions. The cause of the problem needs to be identified and remedied. Bank protection structures and vegetation planting may speed up the recovery process. It may be necessary to revise Allotment Management Plans to include protection of stream or riparian habitat.
E. Improve water quality where needed. Where high summer temperatures are a problem, improving flow conditions through acquisition of water rights or protection of reasonable instream flows will be required. Restoration of streamside vegetation to shade the stream bottom will help. If pollution from agriculture, mining or domestic uses is a problem, reduction of these contaminants would be necessary.
8. Improve biological components of habitat. Another component of habitat work would be the biological restoration of streams by removing nonnative fishes. Reclamation projects using rotenone and other piscicides could be conducted after appropriate environmental assessments and chemical treatment plans were approved. Occasionally it may be possible to consider the lower elevation, transition zone portions streams already reclaimed for Rio Grande cutthroat trout if they research shows are suitable for reintroduction of Rio Grande sucker. Benefits of stocking Rio Grande sucker and perhaps even Rio Grande chub in suitable Rio Grande cutthroat trout waters would be reestablishment of a complete and natural fish community. Along these same lines, white sucker extermination should be done very carefully to prevent extirpation of other native fishes and invertebrates.
Although less efficient, it may be possible to reduce the white sucker biomass in Hot Creek by selective removal of individuals collected during electrofishing surveys.
9. Prevent reintroduction of nonnative fishes in waters managed for Rio Grande sucker. To maintain the stability of the Rio Grande sucker population and perhaps the entire native fish community it is important to prevent the reintroduction of nonnative fishes. Brown trout and northern pike may prey on Rio Grande sucker. Nonnative sucker can hybridize with Rio Grande sucker. This results in introgression of the gene pool and thus loss of pure stocks.
The DOW (as determined by the Colorado Wildlife Commission) has regulatory authority over introductions of some fishes into flowing waters of Colorado. Nonnative fishes have become established in former Rio Grande sucker waters mainly through fish stocking programs conducted by DOW, USFS and the private sector over the years. And, sometimes nonnative species have become established through illegal introductions by individuals. There is precedent for this occurring in waters that have already been reclaimed for indigenous trouts. Such appears to have been the case in the headwaters of the Lake Fork of the Conejos River where large numbers of small brook char and brown trout suddenly appeared in a thriving population of newly established Rio Grande cutthroat trout. Thus, the decision whether to reclaim the a water a second time might include additional social and legal aspects.
10. Promote and enforce fishing regulations to match the needs of the Rio Grande sucker populations. For the most part Rio Grande sucker are unaffected by angling because of their herbivorous food habits. In some cases, it may be necessary to close a stream to seining of bait fish. Decisions on fishing regulations are the responsibility of the Colorado Wildlife Commission and participation will be solicited from all potentially affected interests. Enforcing harvest regulations that adequately protect the Rio Grande sucker populations would be the responsibility of the DOW.
11. Use land management practices conducive to habitat preservation and improvements.
A. Revise and set forth standards and guidelines for Rio Grande sucker habitat management in USFS and BLM land management plans. Guidelines will address the entire watershed in areas with populations of Rio Grande sucker. One biological element of managing watersheds is to provide connections for fish passage among populations in individual streams. In this way, two or more individual populations comprise a larger metapopulation that is resistant to extinction.
B. Develop cooperative management agreements with public agencies, organizations and individuals that have an interest or impact on Rio Grande sucker. Cooperative agreements with the Rio Grande National Forest to include Rio Grande sucker management ideas in a Forest Land Management Plan or with the Rio Grande and Conejos Water Conservation Districts to address sucker management in water use plans are examples. These agreements would strive to meet mutual interests such as maintaining flexibility in land and water management while also moving toward recovery of Rio Grande sucker.
C. Work towards securing instream flow rights in all Rio Grande sucker waters on Federal, State and private lands by filing for water rights through the Colorado Water Conservation Board.
D. Maintain or improve water quality to standards needed by Rio Grande sucker. Stream and lake water quality standards and classifications are under the jurisdiction of the Colorado Health Department, Water Quality Control Division.
12. Monitoring of the effectiveness of actions implemented to protect Rio Grande sucker. The purpose of periodic monitoring is to provide information about the viability of various populations and the stability of the habitat. These data can be used to make decisions about fishing regulations, whether transplants of suckers from the various stocks can be made, and the success of land management plans and practices.
Rio Grande sucker present a challenge as a public relations client. They can be perceived by some people near their habitat areas as "trash fish" that have little or no worth. They also lack some appealing qualities of other threatened or endangered species such as the peregrine falcon, the bald eagle or even the wolf or grizzly bear. The sucker is viewed by some as an obstacle to economic development. Local public sentiment may characterize this species as an impediment to water management and development in portions of the San Luis Valley. Finally, many people are unaware of the species' existence and residents are not adept at identifying the species. Local anglers usually call any small fish they cannot identify as "minnows." Given this view, the information and education program goals would take the form outlined by the USFWS (1990) in the Five-Year Plan for Information and Education relating to endangered fishes in the Colorado drainage.
13. Educate the public on the uniqueness and value of endangered fishes.
14. Increase public understanding and support regarding the recovery of Rio Grande sucker, including support at the local, state and national level for continued funding for the recovery effort.
15. To promote communication and cooperation among the various potentially affected interests of the Recovery Program.
| DFC | Home | Search | Species Index | Area Index | What's New | Comment | |
|
(Dean Hendrickson) |
General information: (E. Phil Pister) |
||||||
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This page last modified: 09 December 2003