STUDY GUIDELINES
FOR
UMPQUA CUTTHROAT TROUT RESTORATION
February, 2000
By the
UMPQUA CUTTHROAT SCIENCE TEAM
With Representatives From:
Oregon Department of Fish and Wildlife
National Marine Fisheries Service
Oregon Watershed Enhancement Board
Bureau of Land Management
U. S. Fish and Wildlife Service
Oregon State University
University of Nevada, Reno
Douglas County
PacifiCorp
Umpqua Basin Watershed Council
Douglas Timber Operators
2
Study Guidelines for Umpqua Cutthroat Trout Restoration
The Umpqua Cutthroat Science Team (UCST) is a voluntary group consisting of local biologists, science community members, Oregon State University, state and federal agencies, private biologists, and the Umpqua Watershed Council. Leadership of the team rests with the Oregon Department of Fish and Wildlife.
The UCST has no direct funding. Its role is to provide information and assist with the establishment of work priorities of those undertaking work on Umpqua cutthroat trout. The UCST was formed as a result of the federal listing of the Umpqua River cutthroat trout as endangered on August 9, 1996. On March 9, 1999, NMFS proposed to delist the Umpqua cutthroat trout. This decision was based on new information expanding the Evolutionarily Significant Unit (ESU) to include the Oregon coast from Cape Blanco north to the Columbia River. The final decision is due in April, 2000. Regardless of the final decision, the sea-run form of the Umpqua cutthroat trout will remain in a very precarious position.
The primary goal of the team was to prepare a written report that identified the best available and relevant scientific information to parties involved in reviewing the status, and/or engaged in the recovery and restoration efforts for the Umpqua cutthroat trout that would lead to successful recovery of the species. Although the Umpqua cutthroat has been recommended for delisting, the team feels that there are still many unanswered questions regarding the species. The UCST is committed to continuing work that will further develop knowledge of the species and enhance the population.
To that end, the team has developed a computerized bibliography of known material available on cutthroat trout in the Umpqua Basin as well as much of the Pacific Coast. This material is available in an Excel file from Oregon Department of Fish and Wildlife, 4192 N. Umpqua Highway, Roseburg, OR 97470. It will soon also be available on the ODFW internet site at: www.dfw.state.or.us. Also to be made available at that site is a consolidated bibliography of all references from the proceedings of the sea-run cutthroat trout conference published in 1997.
With that work completed the team began addressing the needs for additional information on Umpqua cutthroat trout that would assist in the broadening of knowledge of the species as well as provide guidance to people or groups who wished to undertake projects or research that would contribute to the life history and habitat of the species. This report provides three goals with relevant objectives, recommended studies and projects, and functions as a study guideline for Umpqua cutthroat restoration.
The goals are:
Goal 1
Determine the abundance and distribution of Umpqua cutthroat trout, both historic and present, and determine the preferred habitat by life stage. Study factors affecting Umpqua cutthroat trout.
Goal 2
Determine the migration patterns and behavior of all Umpqua cutthroat trout and the relationships among sea-run, fluvial, and resident life-history forms.
Goal 3
Determine and establish studies that clarify the genetic structure of Umpqua cutthroat trout. Promote the undertaking of well-defined genetic studies that will find markers for Umpqua cutthroat trout that identify the three life-history forms.
To provide the information in this report the UCST has identified six priorities.
1. Identify existing knowledge relevant to each question. This has been largely accomplished with the development of the computer bibliography that is available at the ODFW locations noted above.
2. Because of its precarious status, emphasis should be placed on studies that increase knowledge of the anadromous life form of Umpqua cutthroat trout.
3. Apply current knowledge to identify information gaps. The team and others have reviewed information that has led to identification of the objectives in this report.
4. Identify studies that fill information gaps within the context of each objective.
5. Conduct reviews of new and ongoing studies to ensure consistency of methods and maximize their value by keeping up-to-date as new information becomes available.
6. As work on the Umpqua cutthroat trout is completed by anyone in the future there needs to be a method of sharing the information with all interested parties through regular updates of the computer bibliography.
Specific projects are also recommended so that direct progress can be made toward the goals. The UCST suggests that these are not all the questions nor are the recommended projects or solutions necessarily fitted for individual interests, geographic area, or ability. The UCST hopes that the objectives have enough flexibility to accommodate whatever relevant work may be undertaken. What is most important is that future studies be done in a systematic manner and be tied to the goals established by the UCST.
The UCST encourages all agencies, groups, and individuals working with fish and habitat in the Umpqua Basin to consider how their work might assist in answering all or parts of the following questions. Comments are welcome. THE UCST would like the opportunity to review study plans and results for all efforts that could involve Umpqua cutthroat trout.
Following are the goals with objectives, recommended studies, and projects.
Goal 1
Determine the abundance and distribution of Umpqua cutthroat trout, both historic and present, and determine the preferred habitat by life stage. Study factors affecting Umpqua cutthroat trout.
Information about the abundance and distribution of Umpqua Basin coastal cutthroat trout is complicated because of the diverse life history and migratory behavior of this species.
A key assumption for determining optimum population levels is to determine the condition of the habitat. Fishery managers operate on the belief that all other things being equal, better habitat will produce more fish. Many physical and biological factors determine the quality of the habitat, including available spawning gravel, summer and winter rearing habitat, open migratory corridors, stream temperature, and food supply.
A limiting habitat factor is an upper ceiling that keeps a population below what other habitat factors can support. A thorough understanding of habitat inventory data combined with data on population distribution and abundance will allow fishery managers to predict optimum populations levels.
Definition of potentially suitable habitat should involve linking empirical models of fish distribution with a geographic information system (GIS) to delineate the amount and distribution of suitable habitat in drainage networks. Stream size and temperature are likely to be among the important factors determining the limits to potentially suitable habitat. Linking habitat models to GIS will reveal a network of suitable areas of habitats or habitat "patches" within the Umpqua Basin. Within this patch network, information on physical, biotic, and geomorphic landscape characteristics can be summarized. These data can be linked to presence and absence of fish to develop probabilistic models of species occurrence within patch networks.
This approach to classification can contribute to prioritization of efforts to restore, manage, and monitor aquatic habitats for coastal cutthroat trout and associated species. For example, management should be focused first on habitats known to support cutthroat trout. With predictive models in place, the probability of occurrence of cutthroat trout in presently occupied habitats and unsampled areas can be better understood and future population surveys can be performed. Finally, if metapopulation dynamics are important, currently unoccupied habitats can be prioritized in terms of management to facilitate future recolonization, either by natural means or reintroductions. This kind of research would be very complementary to information from genetic surveys within the basin and for updating current GIS-based habitat assessments, such as the Umpqua Land Exchange project.
Adequate support for detailed analysis of survey data and study results should be equal in priority to data collection.
1. Is there a record of historic and potential spawning sites?
There is very little information regarding historic spawning sites. What little is known about historic spawning sites can be obtained from records in the current bibliographic database.
Knowledge of historic and potential spawning sites is important for establishing the requisite spawning baseline for a species. From this examination, information gaps can be identified and needs for future work identified. Potential spawning sites can be determined from studies designed to answer current spawning site questions, and applying information about habitat preferences for the species.
Recommended Studies and Projects
· Conduct literature search of spawning locations and mapping of known historic sites.
· Link information to location of current spawning sites to determine what
has been lost.
· Interview "old timers" as a source of information.
· Identify potential spawning sites based on habitat and spawning surveys, with special emphasis
placed on the effects of barriers.
2. What is the location of current spawning sites?
In the Umpqua Basin, little is known about the location, timing, or duration of cutthroat trout spawning, including anadromous forms of the species. Before any discussion of timing or duration occurs, however, location must be determined. Locating spawning sites of cutthroat is complicated by the relatively low population numbers of anadromous and fluvial fish and dispersed nature of the species. This does not diminish the value of gathering information about spawning sites. Any study designed to provide meaningful information on spawning sites would need to take into account all forms of the species, potential spawning locations, and should bracket known spawning times. A study should be broad enough to consider all potential spawning periods, and draw upon all existing information contained within the cutthroat trout database.
Study design would need to be statistically valid. This would likely include apportioning the basin into study areas, with a stream reach-based approach designed to provide assurance that all habitat types were evaluated to a reasonable extent. Sampling of study reaches would follow existing protocols.
All information gathered would be detailed on a GIS layer so it could be incorporated into appropriate models for later evaluation within the context of the entire population of spawning sites.
Recommended Studies and Projects
· Conduct extensive spawning surveys.
· Conduct radiotelemetry studies for adult cutthroat trout
· Characterize the attributes of known spawning areas.
· Conduct studies by dividing the basin into subbasins and then subsample.
· Conduct random, basin-wide spawning surveys from December through April.
Every 10 days
One mile reaches
· Conduct specific watershed spawning surveys.
One time per month
Full watershed, once per month, December to April
Pick one or two watersheds per subbasin
· From above information, develop index sites that lead to species abundance.
3. Are there counting sites other than Winchester Dam?
The only long-term monitoring station in the basin is the counting window located at Winchester Dam. The many life forms of coastal cutthroat trout, with their respective migration strategies, make monitoring of these life forms problematic. While information from this site has been used to document the decline of the anadromous form of coastal cutthroat trout, the question regarding its representation of the basin's overall population is important.
There is a need to develop a long-term monitoring strategy for coastal cutthroat trout in the basin. This strategy must include methods to document levels of resident, fluvial, and anadromous forms of this species. This monitoring strategy must also be tied to where habitat restoration work is being conducted to provide a possible means to evaluate fish response to the restoration effort. Studies must also be designed to provide a broad representation of the Umpqua Basin.
Recommended Studies and Projects
· Establish other monitoring/counting sites so as to maximize coverage and make the best use of
resources in the basin.
· Trap during the migration period in most areas with some year-round sampling at selected sites
· Establish some site-specific, small basin, long-term research.
· Potential upstream monitoring sites
Smith River Falls
Steamboat Creek Falls
Rock Creek diversion dam fishway
South Umpqua Falls
Calapooya Creek fishway
Little River Falls
· Potential downstream monitoring sites
Cedar Creek on Steamboat Creek
Mainstem North Umpqua
Williams Creek
Upper Smith River
West Fork of Smith River
Lower Umpqua River tributaries
4. What are the effects of inter- and intraspecific competition?
There is very little information regarding competition between cutthroat trout and other species of fish. There is also lack of information regarding competition among the three life-history forms of cutthroat trout. Competition for a resource exists only if the resource is limited. Resources of primary concern include streambed habitat, areas of suitable water temperature, and prey. If spawning, rearing, and refugia habitat with appropriate water temperature were limited, or if food were limited, the competitive interactions with native and non-native species of fishes could be adversely affecting the wild populations of Umpqua Basin coastal cutthroat trout. Because Umpqua cutthroat trout have co-evolved with the native competitors of the basin, competition with introduced species of fish may be most worthy of study. Primary areas of concern are the introduction of smallmouth bass in the Umpqua River, interaction with rainbow trout, and competition with other species in the estuary.
Recommended Studies and Projects
· Undertake studies to determine food availability for cutthroat trout.
· Relate competition studies to habitat needs of various species.
· Search for historic information on the effects of introducing
other species into cutthroat populations.
· Utilize studies to compare habitats that have only cutthroat with those that have multiple species.
5. What are the effects of predation on Umpqua cutthroat trout?
Predation can affect many parameters of the prey population. These parameters include abundance, distribution, life-history form, body size, age structure, sex ratio, and genetic composition. Under extreme rates of predation, prey abundance and distribution could be severely reduced. Under low to moderate rates of predation, the prey population may benefit from reduced interspecific competition and from the loss of individuals with low genetic fitness. As above, non-native species of predators may merit study.