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21. [Article] Status, Distribution, and Life History Investigations of Warner Suckers, 2006-2010 Information Reports number 2011-02
Abstract -- The Warner sucker Catostomus warnerensis is endemic to the Warner Valley, a subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically abundant ...Citation Citation
- Title:
- Status, Distribution, and Life History Investigations of Warner Suckers, 2006-2010 Information Reports number 2011-02
Abstract -- The Warner sucker Catostomus warnerensis is endemic to the Warner Valley, a subbasin of the Great Basin in southeastern Oregon and northwestern Nevada. This species was historically abundant (Snyder 1908) and its historical range includes three permanent lakes (Hart, Crump, and Pelican), several ephemeral lakes, a network of sloughs and diversion canals, and three major tributary drainages (Honey, Deep, and Twentymile creeks). Warner sucker abundance and distribution has declined over the past century and it was federally listed as threatened in 1985 due to habitat fragmentation and threats posed by the proliferation of piscivorous non-native game fishes (U.S. Fish and Wildlife Service 1985). The Warner Valley is a northeast-southwest trending endorheic basin that extends approximately 90 km (Figure 1). The elevation of the valley floor is approximately 1,370 m and the basin is bound by fault block escarpments, the Warner Rim on the west and Hart Mountain and Poker Jim Ridge on the east. The Warner basin was formed during the middle Tertiary and late Quaternary geologic periods as a result of volcanic and tectonic activity (Baldwin 1974). Abundant precipitation during the Pleistocene Epoch resulted in the formation of Pluvial Lake Warner (Hubbs and Miller 1948). At its maximum extent approximately 11,000 years ago, the lake reached approximately 100 m in depth and 1,300 km2 in area (Snyder et al. 1964; Weide 1975). The Warner sucker inhabits the lakes and low gradient stream reaches of the Warner Valley. The metapopulation of Warner suckers is comprised of two life history forms: lake and stream morphs. The lake suckers display a lacustrine-adfluvial pattern in which they spend most of the year in the lake and spawn in the streams. However, when upstream migration is hindered by low stream flows during drought years or by irrigation diversion dams, lake suckers may spawn in nearshore areas of the lakes (White et al. 1990). Large lake-dwelling populations of introduced fishes in the lakes likely reduce sucker recruitment by predation on young suckers (U.S. Fish and Wildlife Service 1998). Periodic lake desiccation also threatens the lake suckers. The stream suckers display a fluvial life-history pattern and spawn in the three major tributary drainages (Honey, Deep, and Twentymile Creeks). Threats specific to the stream form include water withdrawals for irrigation and impacts from grazing. Stream suckers recolonized the lakes after past drying events (mid-1930’s and early-1990’s). The Recovery Plan for the Threatened and Rare Native Fishes of the Warner Basin and Alkali Subbasin (U.S. Fish and Wildlife Service 1998) sets three recovery criteria for delisting the species. These criteria require that: (1) a self-sustaining metapopulation is distributed throughout the drainages of Twentymile Creek, Honey Creek, and below the falls on Deep Creek, and in Pelican, Crump, and Hart Lakes; (2) passage is restored within and among these drainages so that individual populations of Warner suckers can function as a metapopulation; and (3) no threats exist that would likely threaten the survival of the species over a significant portion of its range. The Oregon Department of Fish and Wildlife’s (ODFW’s) Native Fish Investigations Project conducted investigations from 2006 through 2010 to describe the conservation (recovery) status of Warner suckers. The objectives of our investigations were to: 1) describe the current distribution of suckers in the Warner subbasin, 2) estimate their abundance in the lakes and streams, 3) collect life history information, and 4) describe the primary factors that currently limit the sucker’s ability to maintain a functioning metapopulation, including connectivity/fragmentation of habitats and factors affecting successful recruitment in the lake and stream environments. Previous similar studies were conducted in 1990, 1991, 1994, 1995, 1996, 1997, and 2001 (White et al. 1990; White et al. 1991; Allen et al. 1994; Allen et al. 1995; Allen et al. 1996; Bosse et al. 1997; Hartzell et al. 2001). We addressed these objectives by implementing the following tasks: 1) conducting surveys in Hart and Crump Lakes to describe the distribution and quantify the abundance of Warner suckers, search for evidence of recent recruitment, estimate sucker abundance relative to nonnative fish abundance, and describe certain life history characteristics, 2) tagging suckers with Passive Integrated Transponder (PIT) tags in the lakes and tributaries to estimate growth rates and describe seasonal movements, 3) radio tracking suckers in the lakes and tributaries to describe seasonal movements, 4) fishing screw traps in Warner basin tributaries to monitor downstream movements, 5) operating a trap at a fish ladder on a Warner tributary to assess upstream passage success, 6) conducting surveys in Warner basin tributaries to describe the current distribution of stream resident populations of Warner suckers and to quantify their abundance, 7) describing associations between the distribution of suckers and habitat variables in Twentymile Creek, 8) trapping larval suckers in the tributaries to describe the relative abundance and timing of larval movements, 9) describing life history parameters including growth rates, length frequency distributions, length at maturity, and weight-length relationships, 10) evaluating a nonlethal ageing technique, 11) describing the distribution and abundance of the Warner suckers at Summer Lake Wildlife Management area, where a self-sustaining population became established after fish salvage from Hart Lake during the 1992 drought, and 12) collecting tissue samples for future genetic analyses. This report compiles the results of this work, synthesizes and interprets findings relative to the conservation status of the species, and recommends future studies.
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22. [Article] Oregon North Coast Spring Chinook Stock Assessment – 2005-06 Information Reports 2008-01
Abstract -- Chinook salmon populations of the Oregon coast exhibit two general life history types, classified as either spring-run or fall-run depending on adult life-history traits. Fall chinook are present ...Citation Citation
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- Oregon North Coast Spring Chinook Stock Assessment – 2005-06 Information Reports 2008-01
Abstract -- Chinook salmon populations of the Oregon coast exhibit two general life history types, classified as either spring-run or fall-run depending on adult life-history traits. Fall chinook are present in most Oregon coastal basins, and the Oregon Department of Fish and Wildlife (ODFW) has identified 28 fall chinook populations in this area (ODFW 2005). Spring chinook salmon are found in larger river basins on the Oregon coast, and the upper portions of the Umpqua and Rogue rivers. This is a more limited distribution than coastal fall chinook and includes only 10 populations (ODFW 2005). Oregon coastal fall chinook stocks have been monitored through a set of 56 standard spawning ground surveys, many conducted since the 1950’s. There has not been a similar, consistent, coast-wide monitoring program for Oregon coastal spring chinook spawners. Abundance of these populations has been monitoring through a variety of methods including; freshwater harvest estimates, counts at dams and weirs, summer resting hole counts, and spawning ground surveys. In 1998, the National Marine Fisheries Service (NMFS) reviewed west coast chinook salmon populations in regards to status under the Federal Endangered Species Act (ESA). The NMFS identified a total of 15 Evolutionarily Significant Units (ESUs) of chinook salmon (Myers et al. 1998). Oregon coastal chinook are predominantly in the Oregon Coast ESU (Necanicum River to Elk River). This ESU includes both spring and fall chinook, and was determined to not warrant listing (Federal Register Notice 1998). In 2005, ODFW conducted a review of Oregon native fish status, in regards to the State’s Native Fish Conservation Policy. This review grouped populations by Species Management Unit (SMU), and examined coastal spring and fall chinook populations separately. The review determined the near-term sustainability of the Coastal Fall Chinook SMU was not at risk, but the Coastal Spring Chinook SMU was at risk (ODFW 2005). The Tillamook and Nestucca spring chinook populations were of particular concern because they failed to pass the interim criteria for abundance, productivity, and reproductive independence. Hatchery supplementation of spring chinook has occurred in the Tillamook and Nestucca basins since the early 1900’s. Currently, approximately 450,000 spring chinook smolts are released annually from Trask Hatchery, Cedar Creek Hatchery (Nestucca), and from a STEP program at Whiskey Creek. These hatchery smolts have been mass marked with an adipose fin clip since the 1998 brood year. Therefore, hatchery origin adult spring chinook may now be positively identified by the lack of an adipose fin. Declining trends in wild coastal spring chinook populations have resulted in management actions to target harvest on adipose fin clipped hatchery fish, and to restrict harvest of wild origin fish. Results of status reviews, and changes in management practices have required a more thorough evaluation of stock status for the Tillamook and Nestucca spring chinook populations (Keith Braun, personal communication). Therefore, ODFW developed a monitoring plan for spring chinook in these basins. The monitoring plan identified four project objectives; 1) Determine adult spring chinook abundance in the Trask, Wilson, and Nestucca Rivers, 2) Determine hatchery vs. wild ratios for these three basins, 3) Determine age structure and sex ratios for adult spawners, and 4) Determine distribution and abundance for spring chinook recycled from local ODFW hatcheries. This project began in 2004 with an exploratory season to determine distribution, survey methodology, and feasibility of the proposed protocol. In 2005 and 2006 a more intensive sampling effort was implemented, designed to cover the entire distribution of spring chinook spawning in the Nestucca, Trask, and Wilson rivers. Since 2004, project field work has been funded with Restoration and Enhancement Program (R&E) funds, administered by Oregon Department of Fish and Wildlife. Project administration is covered through existing funding for the ODFW Oregon Adult Salmonid Inventory and Sampling Project (OASIS). Funding from R&E is scheduled to continue through the 2008 spawning season. Further monitoring will require a new funding source for project field work. This report documents results for project Objectives 1 to 4, including the abundance and distribution of spring chinook spawners during 2005 and 2006 in Oregon’s Trask, Wilson, and Nestucca river basins.
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23. [Article] Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced ...Citation Citation
- Title:
- Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced salmon have resulted in substantial changes in many hatchery programs. In 2007 the Oregon Department of Fish and Wildlife terminated a 30-year artificial propagation program for coho salmon in the Salmon River basin after a status assessment concluded that wild population viability was threatened by hatchery effects on salmon productivity (Chilcote et al. 2005). Hatchery-reared coho comprised 50-100% of the naturally spawning population in recent years. Low productivity was reflected in a low spawner to recruit ratio, and life-stage specific survival was lower than that of nearby populations. The temporal distribution of adult spawning in the basin was truncated and peaked 1.5 months earlier relative to the pre-hatchery period and adjacent coastal populations. The cessation of hatchery releases into Salmon River not only removed the primary factor believed to limit productivity of the local population, it also constituted a rare management experiment to test whether a naturally-spawning population can recover from a prolonged period of low abundance after interactions with hatchery-produced coho salmon are eliminated. This report summarizes the results of coho population studies at Salmon River for the first three years after the hatchery program was discontinued. The study in Salmon River is timely because ecological interactions between hatchery and wild fish have been implicated in the reduced survival and decreased productivity of wild coho and other salmonid populations (Nickelson 2003, Buhle et al. 2009, Chilcote et al. 2011). Recent studies involving a diversity of salmonid species and watersheds have shown a negative relationship between hatchery spawner abundance and wild population productivity regardless of the duration of hatchery influence (Chilcote et al. 2011). Yet neither the mechanisms of these productivity declines nor their potential reversibility have been investigated. Recent management changes at Salmon River provide an opportunity to experimentally evaluate coho salmon survival and productivity following the elimination of a decades-long hatchery program. The results will provide new insights into the reversibility of hatchery effects and the rate, mechanisms, and trajectory of response by a naturally spawning coho salmon population. Hatchery programs have been shown to change the timing and distribution of naturally spawning adults, but ecological and genetic influences on the spatial structure and life history diversity of juvenile populations are poorly understood. Conventional understanding of the life history of juvenile coho has presumed a relatively fixed pattern of rearing and migration. However, recent studies have found much greater variation in juvenile life history and habitat-use patterns than previously expected (Miller and Sadro 2003, Koski 2009), including evidence that estuaries may play a prominent role in the life histories of some coho salmon populations. A recent study in the Salmon River basin found considerable diversity in the life histories of juvenile Chinook salmon, including extended rearing by fry and other subyearling migrants within the complex network of natural and restored estuarine wetlands (Bottom et al. 2005). Unfortunately, interpretation of juvenile life history variations at Salmon River was confounded by the Chinook hatchery program, which has concentrated spawning activity in the lower river near the hatchery and may directly influence juvenile migration and rearing patterns. Discontinuation of the coho hatchery program at Salmon River provides an opportunity to quantify changes in juvenile life history following the elimination of all hatchery-fish interactions with the naturally spawning population. Such responses may provide important insights into the mechanisms of hatchery influence on wild salmon productivity and population resilience. Our research integrates adult and juvenile life stages, examines linkages to physical habitat conditions in fresh water and the estuary, and describes variability between juvenile performance and adult returns. It also monitors the coho salmon population across habitat types and life history stages to identify population responses at a landscape scale. We will determine productivity and survival at each salmon life stage and monitor the response of the adult population following the cessation of the coho salmon hatchery program. From these indicators, we will determine the potential resiliency of the coho salmon population, and evaluate the biological benefits or tradeoffs of returning the ecosystem to natural salmon production. Our study design encompasses four population phases: (1) pre-hatchery conditions (Mullen 1979), (2) dominance by hatchery-reared spawners (2008), (3) first generation naturally produced juveniles (2009-2011), and (4) second generation naturally produced juveniles (starting in 2012). This research will validate assumptions about factors limiting coho recovery and determine whether recovery actions have been effective. Here, we report on findings from 2008-2010 to address four principal objectives: 1. Quantify life stage specific survival and recruits per spawner ratio of the coho salmon population before and after hatchery coho salmon are removed from Salmon River. 2. Assess whether the Salmon River coho population is limited by capacity and complexity of stream habitat. 3. Describe the diversity of juvenile and adult life histories of coho salmon in the Salmon River basin, and estimate the relative contributions of various juvenile life histories to adult returns. 4. Determine seasonal use of the Salmon River estuary and its tidally-inundated wetlands by juvenile coho salmon. The field sampling that supported the study on coho salmon also captured Chinook salmon and steelhead and cutthroat trout during routine sampling in the watershed and estuary. This report emphasizes coho salmon results, but also summarizes catch, distribution, and migration data for other salmonids to compare densities and abundances in freshwater and the estuary. Additional results for Chinook, steelhead, and cutthroat are presented in Appendix A. See Stein et al. (2011) for more detailed information on life history diversity, migration patterns, habitat use, and abundance of cutthroat trout.