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Abstract -- The Willamette and Sandy rivers support intense recreational fisheries for spring Chinook salmon (Oncorhynchus tshawytscha). Fisheries in these basins rely primarily on annual hatchery releases ...
Citation Citation
- Title:
- Spring Chinook in the Willamette and Sandy Basins, Progress Reports 2006-2007
Abstract -- The Willamette and Sandy rivers support intense recreational fisheries for spring Chinook salmon (Oncorhynchus tshawytscha). Fisheries in these basins rely primarily on annual hatchery releases of 5–8 million juveniles. Hatchery programs exist in the McKenzie, Middle Fork Willamette, North and South Santiam, Clackamas, and Sandy rivers mainly as mitigation for dams that blocked natural production areas. Some natural spawning occurs in most of the major basins and a few smaller tributaries upstream of Willamette Falls. The Oregon Fish and Wildlife Commission adopted the Native Fish Conservation Policy (ODFW 2003a) and the Hatchery Management Policy (ODFW 2003b) in part to reduce adverse impacts of hatchery programs on wild native stocks. The Native Fish Conservation Policy recognizes that naturally produced native fish are the foundation for long-term sustainability of native species and hatchery programs, and the fisheries they support. Possible risks of artificial propagation programs have been well documented. Hazards include disease transfer, competition for food and spawning sites, increased predation, increased incidental mortality from harvest, loss of genetic variability, genetic drift, and domestication (Steward and Bjornn 1990; Hard et al. 1992; Cuenco et al. 1993; Busack and Currens 1995; NRC 1996; and Waples 1999). Hatcheries can also play a positive role for wild salmonids by bolstering populations, especially those on the verge of extirpation, by providing a genetic reserve as well as providing opportunities for nutrient enrichment of streams (Steward and Bjornn 1990; Cuenco et al. 1993). In the past, hatchery programs and fish passage issues were the focus of spring Chinook salmon management in the Willamette and Sandy basins. Limited information was collected on the genetic structure among basin populations, on abundance and distribution of natural spawning, on rearing and migrating of juvenile salmon, or on strategies for reducing risks that large hatchery programs pose for wild salmon populations. This study is being implemented to gather this information. A schematic of the study plan is shown in APPENDIX A. We conducted work in the main-stem Willamette River above Willamette Falls, and in the Middle Fork Willamette, McKenzie, North Santiam, South Santiam, Clackamas, and Sandy rivers in 2006 and 2007. Basin descriptions and background information on management and fish runs can be found in subbasin plans developed by the Oregon Department of Fish and Wildlife (ODFW 1988, ODFW 1992a, ODFW 1992b, and ODFW 1996). Task headings below cross reference the study plan outlined in APPENDIX A. This report covers tasks that were worked on in late 2005 through early fall 2007.
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472. [Article] 2006 Borax Lake Chub Investigations Progress Reports 2006
Abstract -- Borax Lake chub (Gila boraxobius) is represented by a single population that inhabits a 4.1 hectare geothermally-heated alkaline lake in Harney County, Oregon. The Borax Lake chub is a small ...Citation Citation
- Title:
- 2006 Borax Lake Chub Investigations Progress Reports 2006
Abstract -- Borax Lake chub (Gila boraxobius) is represented by a single population that inhabits a 4.1 hectare geothermally-heated alkaline lake in Harney County, Oregon. The Borax Lake chub is a small minnow endemic to Borax Lake and adjacent wetlands in Oregon’s Alvord Basin (Williams and Bond 1980). Borax Lake is a natural lake, perched 10 meters above the desert floor on sinter deposits, which is fed almost exclusively by thermal groundwater. The Borax Lake chub was listed as endangered under the federal Endangered Species Act in 1982 (U.S. Fish and Wildlife Service 1982). Population abundance estimates obtained in 1991-1996 indicated a fluctuating population ranging from a low of 8,144 fish to a high of 34,634 fish (Salzer 1997). The basis for the Borax Lake chub’s listed status was not population size, but the security of a very limited, unique, isolated, and vulnerable habitat. Because Borax Lake is situated above salt deposits on the desert floor, alteration of the salt crust shoreline could reduce lake levels and the habitat quantity and quality available to Borax Lake chub. At the time of the listing, Borax Lake was threatened by habitat alteration caused by geothermal energy development and alteration of the lake shore crust to provide irrigation to surrounding pasture lands. The Borax Lake chub federal recovery plan, completed in 1987, advocated protection of the lake ecosystem through the acquisition of key private lands, protection of groundwater and surface waters, controls on access, and the removal of livestock grazing (U.S. Fish and Wildlife Service 1987). Numerous recovery measures implemented since listing have improved the conservation status of Borax Lake chub and protection of its habitat (Williams and Macdonald 2003). When the species was listed, critical habitat was designated on 259 hectares of land surrounding the lake, including 129 hectares of public lands and two 65- hectare parcels of private land. In 1983, the U.S. Bureau of Land Management designated the public land as an Area of Critical Environmental Concern. The Nature Conservancy began leasing the private lands in 1983 and purchased them in 1993, bringing the entire critical habitat into public or conservation ownership. The Nature Conservancy ended water diversion from the lake for irrigation and livestock grazing within the critical habitat. Passage of the Steens Mountain Cooperative Management and Protection Act of 2000 removed the public BLM lands from mineral and geothermal development within a majority of the basin. These actions, combined with detailed studies of the chub and their habitat have added substantially to our knowledge of the Borax Lake ecosystem (Scoppettone et al. 1995, Salzer 1992, Perkins et al. 1996). However, three primary threats remain. These include the threat to the fragile lake shoreline, wetlands, and soils from a recent increase in recreational use around the lake (particularly off-road vehicle usage), the threat of introduction of nonnative species, and potential negative impacts to the aquifer from geothermal groundwater withdrawal if groundwater pumping were to occur on private lands outside the protected areas (Williams and Macdonald 2003). Although an increase in abundance is not a goal in the successful recovery of this species, monitoring trends in abundance over time is an important management tool to assess species status. From 1998-2004, data describing the abundance of the Borax Lake chub population are not available. Abundance estimates were obtained from 1986- 1997 by The Nature Conservancy (Salzer 1997) (Figure 1). Abundance estimates for 1986-1990 are not comparable with those obtained in 1991-1997. Prior to 1991, estimates were obtained only from traps set around the perimeter of the lake. In 1991, estimates were obtained from traps set on a regularly spaced grid throughout the lake. A study comparing the methods suggests that prior to 1991 abundance was under estimated, perhaps by as much as 50 percent (Salzer 1992). A recent review of the conservation status of the Borax Lake chub by Williams and Macdonald (2003) cited the lack of recent and ongoing population and ecosystem monitoring as one argument against downlisting or delisting the species at this time. The chub population has experienced substantial fluctuations in abundance over the time period (1986-1997) when abundance data are available (Figure 1). At the time of the review, the most recent abundance estimates that were obtained in 1996 and 1997 were some of the lowest estimates since 1991. Borax Lake chub population abundance estimates from 1986 to 1997 and 2005 to 2006. Horizontal bars represent 95% confidence limits. In 1986-1990 (solid symbols), only the perimeter of the lake was trapped. After 1990 (open symbols) the entire lake was trapped. Estimates are not directly comparable across these time periods. There are limited data on population age structure that offer valuable insight into the productivity of Borax Lake chub. Williams and Bond (1983) examined lengthfrequency data and concluded that the population consisted primarily of age 1 fish, with few age 2 and age 3 fish present. Limited opercle bone aging of chub collected in 1992- 1993 also indicated that most Borax Lake were less than one year of age (67-79%), yet a few individuals were aged at 10+ years (Scoppettone 1995). Because Borax Lake chub are only found in one location and the population is apparently dominated by a single year-class of adults, the species has a high inherent risk of extinction. 3 The objectives of this study were to: 1) obtain a mark-recapture population estimate of Borax Lake chub, and 2) to evaluate ways to reduce handling of Borax Lake chub when monitoring population abundance both by modifying previous mark-recapture protocols and by developing snorkeling survey protocols to use as an alternative to mark-recapture estimates. In addition, we collected data regarding lake temperatures, chub size (age) structure, and the condition of the fragile lake shoreline and outflows.
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473. [Article] 2006 Oregon Chub Investigations Progress Reports 2006
Abstract -- Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette Valley, were federally listed as endangered under the Endangered Species Act in 1993. Factors implicated in the decline ...Citation Citation
- Title:
- 2006 Oregon Chub Investigations Progress Reports 2006
Abstract -- Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette Valley, were federally listed as endangered under the Endangered Species Act in 1993. Factors implicated in the decline of this species include changes in flow regimes and habitat characteristics resulting from the construction of flood control dams, revetments, channelization, diking, and the drainage of wetlands. The Oregon chub is further threatened by predation and competition by non-native species such as largemouth bass Micropterus salmoides, crappies Pomoxis sp., sunfishes Lepomis sp., bullheads Ameiurus sp., and western mosquitofish Gambusia affinis. We continued surveys initiated in 1991 in the Willamette River drainage to quantify the abundance of known Oregon chub populations, search for unknown populations, evaluate potential introduction sites, and monitor introduced populations as part of the implementation of the Oregon Chub Recovery Plan. We sampled a total of 103 sites in 2006. No new populations of Oregon chub were discovered. Thirty-five of the 103 sites were new locations that were sampled for the first time in 2006. Sixty-eight sites, sampled on at least one occasion between 1991-2005, were revisited. We confirmed the continued existence of Oregon chub at 33 locations. These included 23 naturally occurring and 10 introduced populations. Locations of naturally occurring populations were: Santiam drainage (Geren Island, Santiam I-5 Side Channels, Santiam Conservation Easement, Stayton Public Works Pond, Green’s Bridge Backwater, Pioneer Park, Santiam Conservation Easement, and Gray Slough), Mid-Willamette drainage (Finley Gray Creek Swamp), McKenzie drainage (Shetzline Pond and Big Island), Coast Fork Willamette drainage (Coast Fork Side Channels and Lynx Hollow), and the Middle Fork Willamette drainage (two Dexter Reservoir alcoves, East Fork Minnow Creek Pond, Shady Dell Pond, Buckhead Creek, two Elijah Bristow State Park sloughs and an island pond, Barnhard Slough, and Hospital Pond). Introduced populations were located in the Middle Fork Willamette (Wicopee Pond and Fall Creek Spillway Ponds), Santiam (Foster Pullout Pond), McKenzie (Russell Pond), Coast Fork Willamette (Herman Pond), and Mid-Willamette drainages (Dunn Wetland, Finley Display Pond, Finley Cheadle Pond, Ankeny Willow Marsh, and Jampolsky Wetlands). We did not find Oregon chub at 14 locations where they were collected on at least one occasion between 1991-2005 (Jasper Park Slough, Wallace Slough, East Ferrin Pond, Dexter East Alcove, Hospital Impoundment Pond, Rattlesnake Creek, Elijah Bristow Large Gravel Pit, Elijah Bristow Small Gravel Pit, Little Muddy Creek tributary, Bull Run Creek, Camas Swale, Barnhard Slough, Camous Creek, and Dry Muddy Creek). Nonnative fish were collected at most of these locations. We obtained abundance estimates of naturally occurring populations of Oregon chub at 18 locations in the Middle Fork Willamette (East Fork Minnow Creek Pond, Shady Dell Pond, Elijah Bristow State Park Sloughs and Island Pond, Hospital Pond, Dexter Reservoir Alcoves, Haws Pond, and Buckhead Creek), Santiam (Geren Island, Gray Slough, Stayton Public Works Pond, Pioneer Park Pond, and Santiam I-5 Side Channels), McKenzie (Big Island and Shetzline Pond), and Mid-Willamette drainages (Finley Gray Creek) (Table 1). We obtained abundance estimates for 10 introduced populations of Oregon chub, located in Fall Creek Spillway Ponds, Wicopee Pond, Dunn Wetland Ponds, Finley Display Pond, Finley Cheadle Pond, Ankeny Willow Marsh, Jampolsky Wetlands, Foster Pullout Pond, Herman Pond, and Russell Pond. The three largest populations in 2006 were introduced populations. In addition, we evaluated eleven potential Oregon chub introduction sites in the Willamette River drainage. We introduced Oregon chub into the South Stayton Pond, a recently restored site located on ODFW property in the Santiam drainage, from Stayton Public Works Pond and Pioneer Park Pond. The Oregon Chub Recovery Plan (U.S. Fish and Wildlife Service 1998) set recovery criteria for downlisting the species to “threatened” and for delisting the species. The criteria for downlisting the species are: 1) establish and manage 10 populations of at least 500 adult fish, 2) all of these populations must exhibit a stable or increasing trend for five years, and 3) at least three populations meeting criterion 1 and 2 must be located in each of the three recovery areas (Middle Fork Willamette River, Santiam River, and Mid-Willamette River tributaries). In 2006, there were 18 populations totaling 500 or more individuals (Table 1). Thirteen of these populations also met the second criteria. Of the 13 populations meeting criteria 1 and 2, eight were located in the Middle Fork Willamette drainage, three were located in the Mid-Willamette drainage, and two were located in the Santiam drainage. With the addition of one more stable population in the Santiam drainage, the downlisting criteria will be met. Findings to date indicate that Oregon chub remain at risk due to the loss of suitable habitat and the continued threats posed by the proliferation of non-native fishes, illegal water withdrawals, accelerated sedimentation, and potential chemical spills or careless pesticide applications. Their status has improved in recent years, resulting primarily from successful introductions and the discovery of previously undocumented populations.
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474. [Article] 2007 Oregon Chub Investigations Progress Reports 2007
Abstract -- Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette Valley, were federally listed as endangered under the Endangered Species Act in 1993. Factors implicated in the decline ...Citation Citation
- Title:
- 2007 Oregon Chub Investigations Progress Reports 2007
Abstract -- Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette Valley, were federally listed as endangered under the Endangered Species Act in 1993. Factors implicated in the decline of this species include changes in flow regimes and habitat characteristics resulting from the construction of flood control dams, revetments, channelization, diking, and the drainage of wetlands. The Oregon chub is further threatened by predation and competition by non-native species such as largemouth bass Micropterus salmoides, crappies Pomoxis sp., sunfishes Lepomis sp., bullheads Ameiurus sp., and western mosquitofish Gambusia affinis. We continued surveys initiated in 1991 in the Willamette River drainage to quantify the abundance of known Oregon chub populations, search for unknown populations, evaluate potential introduction sites, and monitor introduced populations as part of the implementation of the Oregon Chub Recovery Plan. We sampled a total of 70 sites in 2007. New populations of Oregon chub were discovered at Green Island in the lower McKenzie River and in the Muddy Creek drainage (Linn County). We confirmed the continued existence of Oregon chub at 34 locations. These included 23 naturally occurring and 11 introduced populations. We did not find Oregon chub at nine locations where they were collected on at least one occasion between 1991-2006. Nonnative fish were collected at most of these locations. We obtained abundance estimates of 18 naturally occurring populations and 11 introduced populations of Oregon chub located in the Middle Fork Willamette, Santiam, McKenzie, and Mid-Willamette drainages (Table 1). We introduced additional Oregon chub into the South Stayton Pond in the Santiam drainage and into Cheadle and Display Ponds in the Mid-Willamette drainage. The Oregon Chub Recovery Plan (U.S. Fish and Wildlife Service 1998) set recovery criteria for downlisting the species to “threatened” and for delisting the species. The criteria for downlisting the species are: 1) establish and manage 10 populations of at least 500 adult fish, 2) all of these populations must exhibit a stable or increasing trend for five years, and 3) at least three populations meeting criterion 1 and 2 must be located in each of the three recovery areas (Middle Fork Willamette River, Santiam River, and Mid-Willamette River tributaries). In 2007, there were 20 populations totaling 500 or more individuals (Table 1). Fifteen of these populations also met the second criteria. Of the 15 populations meeting criteria 1 and 2, eight were located in the Middle Fork Willamette drainage, four were located in the Mid-Willamette drainage, and three were located in the Santiam drainage. In 2007, we met the downlisting criteria. Findings to date indicate that Oregon chub remain at risk due to the loss of suitable habitat and the continued threats posed by the proliferation of non-native fishes, illegal water withdrawals, accelerated sedimentation, and potential chemical spills or careless pesticide applications. Their status has improved in recent years, resulting primarily from successful introductions and the discovery of previously undocumented populations.
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475. [Article] Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007
Abstract -- Hood River bull trout are thought to exist as two independent reproductive units (USFWS 2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population is isolated ...Citation Citation
- Title:
- Hood River Bull Trout Abundance, Life History, and Habitat Connectivity, 2007 Progress Reports 2007
Abstract -- Hood River bull trout are thought to exist as two independent reproductive units (USFWS 2004), known as local populations (Rieman and McIntyre 1995). The Clear Branch local population is isolated above Clear Branch Dam, which provides limited downstream fish passage during infrequent and sporadic periods of spill and no upstream passage. Bull trout in this population inhabit Laurance Lake Reservoir and tributaries upstream of Clear Branch Dam. The Hood River local population occurs in the mainstem Hood River and Middle Fork Hood River downstream of the Clear Branch Dam and a small number of adult bull trout migrate each year into the Hood River from the Columbia River (Figure 1). The status of both populations is extremely precarious. The Clear Branch population is at risk of a random extinction event due to low numbers, negative interactions with non-native smallmouth bass, isolation and limited spawning habitat (USFWS, 1998). The Hood River population also appears to be small and is threatened by passage barriers, unscreened irrigation systems, impaired water quality and periodic siltation of spawning substrate by glacial outbursts. Clear Branch bull trout spawn in Clear Branch and Pinnacle Creek. After rearing in these two natal streams for an unknown time period, most are believed to migrate downstream to Laurance Lake Reservoir. Clear Branch bull trout have been documented passing over the dam spillway during high water events (Pribyl et al. 1996) and may provide a recruitment source for the Hood River local population. Adult bull trout tagged at Powerdale Dam have been observed at Coe Branch irrigation diversion and in a trap at the base of Clear Branch dam. These fish may have been attempting to reach spawning areas located upstream of the dam. However, the success of bull trout migrating downstream via the spillway or the possibility of successfully navigating through the diversion network has never been determined. Depending on the water year, the Middle Fork Irrigation District (MFID) may not spill at all, or the timing of the spill may not coincide with the timing of downstream migration, which is currently unknown (East Fork Hood River and Middle Fork Hood River Watershed analysis). Smallmouth bass were discovered in Lake Laurance Reservoir in the 1990s. Creel surveys have shown that large adult bass are caught occasionally in the reservoir and schools of bass fry have been seen by district fish biologist (Rod French, ODFW, personal communication), suggesting that they are spawning successfully. This illegal introduction poses a potential threat to the Clear Branch bull trout population, but its magnitude is unknown because the bass population size and degree of interaction between the two species are unknown. Bull trout and smallmouth bass have significantly different temperature preferences and tolerances, with bull trout being one of the most sensitive coldwater species and bass being a warm water species. Lake Laurance, a relatively high-altitude reservoir at 890 m (2,920 feet), does not provide ideal bass habitat so these two species may have largely non-overlapping distributions or differing activity periods (Terry Shrader, ODFW warmwater fish biologist, personal communication). However, based on past reservoir temperature data (Berger et al. 2005), there are periods in the reservoir when there is potential for bull trout and bass interaction: periods when bull trout are susceptible to bass predation and when juvenile fish might compete for resources. Spawning activity of the Hood River local population has been observed in a few locations within the Middle Fork of Hood River (Figure 1). Although consistent and extensive spawning areas for this population are not known, some of the locations where juvenile rearing or potential bull trout redds have been observed include the Middle Fork Hood River and some of its tributaries: Bear Creek, Compass Creek and Coe Branch (USFWS 2004). However, Coe Branch, Compass Creek, and the Middle Fork are glacial streams with a high volume of sand and silt which may compromise spawning success. No bull trout spawning or rearing has been observed on the East and West Forks of Hood River. The Middle Fork and mainstem Hood River provide foraging, migration and overwintering habitat. Hood River bull trout are also known to migrate into the Columbia River. Two bull trout tagged at Powerdale Dam (RK 7.2 of mainstem Hood River) were recovered near Drano Lake in Washington State; and one was captured 11 kilometers downstream of the confluence of the Hood and Columbia Rivers (USFWS 2004). Every year (usually between May and July), adult bull trout, presumably migrating upstream from the Columbia River, are captured and anchor tagged at Powerdale Dam. Although some of these tagged fish have been observed upstream (one in Coe Branch and three below Clear Branch dam), the spawning destination of fluvial adults within the Hood River basin is largely unknown. Dispersing juvenile bull trout and migrating adults in this local population are threatened by flow diversions with inadequate screening and passage facilities. Several structures are suspected to impede upstream migration or entrain juvenile and adult bull trout into irrigation works (Pribyl et al. 1996, HRWG 1999). These structures include: the diversion at Clear Branch Dam (passage and screening), Coe Branch (passage and screening), and the Farmers Irrigation District diversion (screening) on the mainstem Hood River (HRWG 1999). However, little research has been conducted to assess the impacts of these structures on migrating bull trout. Beyond a general knowledge of the distribution of Hood River bull trout and the nature of anthropogenic factors that potentially restrict their life history and habitat connectivity, little is known about this recovery unit. Baseline information about adult abundance is lacking for both local populations, the potential of a source (Clear Branch) and sink (Hood River) relationship between the two local populations has not been explored, and the migratory life history of adult fish caught at Powerdale Dam is unknown. The degree to which irrigation and hydropower diversions hamper connectivity within the Hood River basin is also poorly understood. Migratory life histories have been viewed as key to species persistence (Rieman and McIntyre 1995; Dunham and Rieman 1999), and understanding movement patterns and associated habitat requirements are critical to maintaining those migratory forms (Muhlfeld and Morotz 2005; Hostettler 2005). Gaining this information is also critical to evaluating bull trout recovery in the Hood River Subbasin (Coccoli 2004). The Oregon Department of Fish and Wildlife (ODFW) initiated a study in 2006 to improve our understanding of the abundance, life history, and potential limiting factors of the bull trout in this recovery unit. This report describes findings for the first two years of the study (2006-2007). Specific study objectives for the first two years were: 1. Determine the migratory life history of Hood River bull trout and assess the potential impacts of flow diversions and two new falls on the Middle Fork Hood River (scoured by the November 2006 glacial outburst) on bull trout migrations. 2. Determine current distribution of bull trout reproduction and early rearing in historical and potential bull trout streams in the Hood River Subbasin. 3. Determine the juvenile and adult life history the Clear Branch local population and develop a statistically reliable and cost-effective protocol for monitoring the abundance of adult Clear Branch bull trout. 4. Assess the potential impact of smallmouth bass on bull trout in Laurance Lake Reservoir.
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476. [Article] Oregon Chub Investigations, Progress Report 2001
Abstract -- Populations of Oregon chub Oregonichthys crameri, endemic to the Willamette Valley, have been drastically reduced. Factors in the decline of this fish include changes in flow regimes and habitat ...Citation Citation
- Title:
- Oregon Chub Investigations, Progress Report 2001
Abstract -- Populations of Oregon chub Oregonichthys crameri, endemic to the Willamette Valley, have been drastically reduced. Factors in the decline of this fish include changes in flow regimes and habitat characteristics resulting from the construction of flood control dams, revetments, channelization, diking, and the drainage of wetlands. The Oregon chub is further threatened by predation and competition by non-native species such as largemouth bass Micropterus salmoides, small mouth bass M. dolomieui, crappies Pomoxis sp., sunfishes Lepomis sp., bullheads Ameiurus sp., and western mosquitofish Gambusia affinis. We surveyed in the Willamette River drainage in April-October 2000 to quantify existing Oregon chub populations, search for unknown populations, evaluate potential introduction sites, and monitor introduced populations. We sampled a total of 77 sites in 2000. We collected Oregon chub for the first time from Barnard Slough in the Middle Fork Willamette drainage. Oregon chub were last collected from this location in 1983 (Bond 1984). Thirty-one of the 77 sites were new sites that were sampled for the first time in 2000. Forty-six sites, sampled in 1991-1999, were revisited. Three sites were sampled twice. We confirmed the continued existence of Oregon chub at 20 locations. These include naturally occurring populations in the Santiam drainage (Geren Island, Santiam Conservation Easement, Gray Slough, Santiam 1-5 backwaters, Pioneer Park backwater, Santiam Public Works Pond), Mid-Willamette drainage (Finley Gray Creek Swamp) and Middle Fork Willamette drainage (Dexter Reservoir Alcoves, East Fork Minnow Creek Pond, Shady Dell Pond, Buckhead Creek, Oakridge Slough, Elijah Bristow State Park, Rattlesnake Creek, and Hospital Pond) and introduced populations in the Middle Fork Willamette (Wicopee Pond, Fall Creek Spillway Ponds), Santiam (Foster Pullout Pond), and Mid-Willamette drainages (Dunn Wetland, Finley Display Pond). Oregon chub were not found at several locations (Jasper Park Slough, Wallace Slough, East Ferrin Pond, Dexter East Alcove, Hospital lmpoundment Pond, Logan Slough, Green's Bridge Backwater, Camas Swale) where they were collected on at least one occasion between 1991-1999 (Scheerer et. al. 1992; 1993; 1994; 1995; 1996; 1998; 1999; 2000; Scheerer and Jones 1997). Non-native fish were common in off-channel habitats that were surveyed in the Willamette River drainage. Non-native fish were collected from 23 of the 31 new sites sampled in 1999 (74%); no fish were collected at three locations (10%). Western mosquitofish and centrarchids (largemouth bass and bluegill) were the most common non-native fish collected. Oregon chub were introduced into Menear's Bend Pond in the Santiam River drainage in the October 2000. Additional Oregon chub were introduced into Foster Pullout Pond in October 2000, to supplement the 85 fish introduced in 1999. In the summer of 2000, a habitat enhancement project creating new habitat to benefit Oregon chub was completed in the Long Tom drainage (Mid-Willamette River). Seven potential Oregon chub reintroduction sites were monitored and evaluated. These included four sites in the Mid-Willamette River drainage (Finley National Wildlife Refuge Beaver and Cattail Ponds, Ankeny National Wildlife Refuge Dunlin-Woodduck Pond, Long Tom Ranch Pond), one site in the Santiam River drainage (Menear's Bend Pond), one site in the McKenzie River drainage (Russell Pond), and one site in the Coast Fork Willamette drainage (Layng Pond). Estimates of abundance were obtained for naturally occurring populations of Oregon chub in East Fork Minnow Creek Pond, Shady Dell Pond, Elijah Bristow State Park Sloughs, Hospital Pond, Dexter Reservoir Alcoves, Buckhead Creek, Oakridge Slough, Santiam Conservation Easement Sloughs, Geren Island Ponds, and Finley Gray Creek Swamp. Five of these populations showed an increase in abundance in 2000 (East Fork Minnow Creek Pond, Shady Dell Pond, Middle Buckhead Creek, Dexter Reservoir Alcoves, Finley Gray Creek Swamp). Four populations decreased in abundance (or remain depressed) in 2000 (Geren Island, Santiam Conservation Easement, Elijah Bristow Sloughs, Oakridge Slough) (Table 1 ). Abundance estimates for introduced populations of Oregon chub were also obtained. The Oregon chub population in East Ferrin Pond declined from 7,200 fish in 1997 to O fish in 2000, and is presumed extinct. The Oregon chub population in the Fall Creek Spillway Pond totaled 5,030 fish in 2000, compared to 6,300 fish in 1999. The Oregon chub population in Wicopee Pond expanded dramatically from ~50 fish in 1999 to 4,580 fish in 2000. The Oregon chub population in the Dunn Wetland Ponds increased from 4,860 fish in 1999 to 14,090 fish in 2000. The Oregon chub population in Finley Display Pond increased from 360 fish in 1999 to 1,750 fish in 2000. Three of the four largest populations in 2000 were introduced populations. The Middle Fork Willamette River drainage supported the largest number of Oregon chub populations (n=12), followed by the Santiam drainage (n=B), and the Mid-Willamette drainage (n=5). The most abundant Oregon chub populations were found in the Middle Fork Willamette and Mid-Willamette drainages. The Oregon Chub Recovery Plan (U .S. Fish and Wildlife Service 1998) set a recovery goal for downlisting the species to "threatened" and for delisting the species. The criteria for downlisting the species was to establish and manage ten populations of at least 500 adult fish. All populations must exhibit a stable or increasing trend for five years. At least three populations must be located in each of the three sub-basins (Middle Fork Willamette River, Santiam River, Mid-Willamette River tributaries). In 2000, there were 11 populations totaling 500 or more individuals and six of these populations exhibited a stable or increasing trend for the past five years (Table 1 ). Five of these six populations were located in the Middle Fork Willamette drainage. In summary, Oregon chub remain at risk due to their limited distribution compared with their historic geographic range in the Willamette Valley, the loss of suitable habitat and the continued threats posed by the proliferation of non-native fishes, illegal water withdrawals, unauthorized fill and removal operations, and potential chemical spills or careless pesticide applications.