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Oregon Chub

Photo of Oregon Chub (Rick Swart, ODFW)

Scientific Name: Oregonichthys crameri

Status: Delisted due to recovery

Recent Activity: On February 17, 2015, the USFWS announced the removal of the Oregon chub, and its critical habitat, from the list of Endangered and Threatened Species, and the Oregon chub became the first fish ever to be delisted due to recovery.

Potential Range Map

  • Introduction

    The Oregon chub was listed as endangered in 1993. A recovery plan was published in 1998. Critical habitat was designated on March 10, 2010. Due to the successful implementation of the recovery plan, the species' status improved, and on April 23, 2010, the USFWS changed the Endangered Species Act classification of the Oregon chub from endangered to threatened. On February 17, 2015, the USFWS announced the removal of the Oregon chub, and its critical habitat, from the list of Endangered and Threatened Species.

    Historical Status and Current Trends

    Oregon chub are endemic to the Willamette River drainage of western Oregon. Historical information on the species is sparse, however records indicate that Oregon chub were well distributed through the broad alluvial plains of the Willamette River and its tributaries.  Oregon chub were documented from the Clackamas River near Oregon City upstream to Oakridge on the Middle Fork Willamette River.  In addition, Oregon chub were also historically documented in other Willamette River tributaries, including the Luckiamute River, Santiam River, Calapooia River, Mary’s River, Long Tom River, McKenzie River, and Coast Fork Willamette River basins.

    When the species was petitioned for listing in 1990, there were eight known populations.  All historic populations along the main stem Willamette River had been extirpated, and the remaining populations were located on the tributaries.  By 2007, there were 38 known populations and this met the recovery criteria for downlisting (changing the classification from endangered to threatened).  The USFWS downlisted Oregon chub to threatened status in 2010.  In 2012, there were 79 known populations of Oregon chub, and the species met the recovery criteria for delisting (removal from the Endangered Species Act due to recovery).  The USFWS published the final rule to delist the Oregon chub in 2015. 

    Monitoring and conservation of the Oregon chub has continued following the species removal from the Endangered Species Act.  Building upon the success of the recovery plan, a multi-agency group completed a post-delisting monitoring plan to guide conservation of the species for nine-years following delisting.  In 2019, there were 133 known populations of Oregon chub, and the species is well distributed throughout its historic range. Naturally occurring populations of Oregon chub have been documented in the Molalla River and Yamhill River, Willamette River tributaries where the species had not been documented historically.  In 2019, Oregon chub were discovered on the mainstem Willamette River, an apparent natural recolonization from a neighboring tributary, and the first documented observation of the species in this historic habitat in over 50 years.

    Description and Life History

    The Oregon chub is a small minnow with an olive-colored back grading to silver on the sides and white on the belly. Adults are typically less than nine centimeters (3.5 inches) in length. Scales are relatively large with fewer than 40 occurring along the lateral line; scales near the back are outlined with dark pigment. Adults feed in the water column on the tiny larvae of aquatic invertebrates, such as mosquitos and other insects. Spawning occurs from the end of April through early August when water temperatures are between 16 degrees and 28 degrees C (60 degrees and 82 degrees F). Only males larger than 25 millimeters (1 inch) spawn, and males more than 35 millimeters (1.4 inches) defend territories in or near vegetation. Females can lay several hundred eggs.

    Habitat

    Oregon chub are found in slack water off-channel habitats such as beaver ponds, oxbows, side channels, backwater sloughs, low gradient tributaries, and flooded marshes. These habitats usually have little or no summer water flow, silty and organic substrate, and aquatic vegetation as cover for hiding from predators and spawning. The average depth of Oregon chub habitats is typically less than two meters (six feet) and the summer water temperature typically exceeds 16 degrees C (61 degrees F). Adult Oregon chub seek dense vegetation for cover and frequently travel in the mid-water column in beaver channels or along the margins of aquatic plant beds. Larval chub congregate in shallow near shore areas in the upper water column. Juvenile Oregon chub venture farther from shore into deeper areas of the water column. In the winter months, Oregon chub can be found buried in the detritus or concealed in aquatic vegetation. Fish of similar size classes school and feed together. In the early spring, Oregon chub are most active in warm, shallow habitats.

    Reasons for Decline

    Historically, the Willamette River was a dynamic, braided channel with many side channels, meanders, oxbows, and overflow ponds that provided habitat for the chub. Periodic flooding of the river created new Oregon chub habitat. The construction of flood control projects and dams, however, changed the Willamette River significantly, and prevented the formation of Oregon chub habitat. The species was further threatened by the widespread proliferation of nonnative warmwater fish species, such as largemouth bass, sunfishes, and bullheads, which compete with or predate upon Oregon chub. Other factors responsible for the decline of the chub include: habitat alteration; accidental chemical spills; runoff from herbicide or pesticide application on farms and timberlands or along roadways, railways, and power line rights-of-way; the application of rotenone to manage sport fisheries; desiccation of habitats; unauthorized water withdrawals; diversions, or fill and removal activities; sedimentation resulting from timber harvesting in the watershed.

    Conservation Measures

    In 1998, the U.S. Fish and Wildlife Service published a recovery plan for the Oregon chub. The goal of this plan was to reverse the decline of the Oregon chub by protecting and enhancing existing wild populations, re-introducing chub into suitable habitats throughout its historic range, targeted research to better inform management, and increasing public awareness and involvement. The recovery of the Oregon chub was due to the successful implementation of the recovery plan. Following the delisting in 2015, the monitoring and management of the species moved to a post-delisting monitoring plan. Built on the success of the recovery plan, this is a nine-year plan to ensure that Oregon chub remains secure following the removal of Endangered Species Act protections. The U.S. Forest Service, Army Corps of Engineers, and the Oregon Department of Fish and Wildlife have active programs to monitor and conserve the Oregon chub. The McKenzie River Trust, a nonprofit land trust, the Oregon Parks and Recreation Department, and USFWS Willamette Valley National Refuge Complex are cooperators on the post-delisting monitoring plan. Careful and coordinated planning, management, and protection of Oregon chub habitat is necessary for the survival of this little minnow.  A variety of federal, state, watershed councils, local governments, and local Tribes are partners working to sustain the recovery of the Oregon chub.

    Approximately forty percent of Oregon chub habitats exist on privately owned property. The voluntarily actions of private citizens made significant contributions to the recovery of the species, primarily by enhancing and protecting existing habitats, creating and establishing new habitats, reducing the proliferation of nonnative fish

    References

    U.S. Fish and Wildlife Service.  2015.  Removing the Oregon Chub From the Federal List of Endangered and Threatened Wildlife. FR (80):9125-9150

    U.S. Fish and Wildlife Service. 2014. Post-delisting Monitoring Plan for the Oregon Chub (Oregonichthys crameri).  Portland, Oregon.  45 pp. 

    U.S. Fish and Wildlife Service. 2010. Reclassification of the Oregon Chub From Endangered to Threatened. FR (75):21179-21189

    U.S. Fish and Wildlife Service. 2010. Designation of Critical Habitat for the Oregon Chub. Federal Register.

    U.S. Fish and Wildlife Service. 1998. Recovery Plan for the Oregon Chub. Portland, OR. 86pp.

    U.S. Fish and Wildlife Service. 1993. Determination of Endangered Status for the Oregon Chub. FR (58):53800-53804.

     

    Last updated: February 25, 2020

     

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