The Oregon Chub Makes Its Way Toward Recovery

by Kim Garner, Brian Bangs, and Paul Scheerer

The Oregon chub, a small minnow found only in the Willamette River Basin in western Oregon, has rebounded from the brink of extinction.

Photo Credit: USFWS

It’s a small minnow in an area known for its large salmon, but the Oregon chub (Oregonichthys crameri) has garnered a lot of attention from federal and state agency biologists, academic professionals, land managers, and many others.

Oregon chub are unique to the Willamette River Valley of western Oregon. They inhabit off-channel habitat, such as beaver ponds, oxbows, stable backwater sloughs, and flooded marshes. In the last 100 years, these habitats have been drastically reduced due to changes in seasonal flows as a result of the construction of dams, channelization of the Willamette River and its tributaries, and draining of wetlands for bottomland agriculture. This loss of habitat, combined with predation by introduced non-native game fishes, led to a sharp decline in Oregon chub abundance and a restricted distribution.

The chub was listed as endangered under the Endangered Species Act in 1993, when there were only eight known populations remaining. As a result of the efforts of multiple conservation partners, the status of the Oregon chub has improved steadily since the time of listing, and in 2010 the U.S. Fish and Wildlife Service (Service) recognized its improved condition by changing its status from endangered to the less critical category of threatened.

Oregon Department of Fish and Wildlife staff with private landowners Dennis and Judy Ellison, after introducing Oregon chub into their pond. The Ellison's are participating in the Programmatic Safe Harbor Program.

Photo Credit: USFWS

The fish's improved status is attributed to successful introduction of Oregon chub into new locations within their historical range and the discovery of new, previously undocumented populations.

The improved status is also due to the efforts of the Oregon Chub Working Group, which was formed in 1991, with participating representatives from the Service, Oregon Department of Fish and Wildlife, U.S. Army Corps of Engineers, the U.S. Forest Service, Oregon State University, and the McKenzie River Trust. The group conserves and restores habitat for the Oregon chub and raises public awareness of the species' plight.

Cooperation of private landowners has also been instrumental to progress towards the species' recovery and, through the Service's Partners for Fish and Wildlife Program, has resulted in several habitat restoration projects and reintroductions into suitable habitats on private lands.

In fact, one of the most abundant chub populations was an introduced population that occurs on private property. In 2010, a Programmatic Safe Harbor Agreement between the Service and the Oregon Department of Fish and Wildlife gave assurances that additional regulatory restrictions under the ESA would not be required of landowners who are willing to implement actions that conserve Oregon chub on their land. To date, seven landowners have enrolled suitable chub habitat on their land in the Safe Harbor Agreement, and have introduced Oregon chub into these habitats.

Brian Bangs, Oregon Department of Fish and Wildlife biologist, freeze-brands an Oregon chub for the marking study.

Photo Credit: USFWS

Improving habitat has also been tackled by federal and state agencies. The U.S. Army Corps of Engineers operates several large dams – primarily for flood control and power generation – in the Willamette River Valley. Their recent river flow management plans have sought to restore floodplain processes by altering the volume and timing of water releases from dams to mimic historical flows and reconnect floodplain habitats. They are also working closely with ODFW to conduct a study to identify the flow levels, temperature regimes, and habitat characteristics that may allow Oregon chub to better co-exist with non-native fishes in connected habitats.

Additionally, a marking study by ODFW is currently underway to detect movement of Oregon chub between populations. Movement between habitats is important to maintain genetic diversity. But, marking a 2-inch fish has its challenges. Two marked Oregon chub were recently discovered moving upstream between habitats—the first time such movement has been documented.

Building on the success of these partnerships, the momentum of Oregon chub recovery has continued and the species has recently met the criteria for delisting laid out in the recovery plan. With 75 known populations as of 2012, biologists are enthusiastic that a recommendation to delist the chub will be forthcoming in the near future.

Kim Garner, a fish and wildlife biologist in the Service's Oregon Fish and Wildlife Office, can be reached at kim_garner@fws.gov or 503-231-6926. Brian Bangs, a fisheries biologist with the Oregon Department of Fish and Wildlife, can be reached at brian.bangs@oregonstate.edu. Paul Scheerer, a fisheries biologist with the Oregon Department of Fish and Wildlife, can be reached at paul.scheerer@oregonstate.edu.