2006 OPRD- Oregon Chub Population Monitoring on Oregon State Park Lands Progress Reports 2006

Identification Information

Citation

Originator: Scheerer, P.D., P.S. Kavanagh, B.L. Bangs and S. E. Jacobs

Publish Date: 2007

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Cedric Cooney

Job Position: Natural Resources Data and Systems Manager

Telephone: 503-947-6094

E-Mail Address: cedric.x.cooney@odfw.oregon.gov

Description

Abstract: Oregon chub Oregonichthys crameri, small minnows endemic to the Willamette River drainage of western Oregon (Markle et al. 1991), were federally listed as endangered under the Endangered Species Act in 1993 (Markle and Pearsons 1990; Rhew 1993). This species was formerly distributed throughout the Willamette River Valley (Snyder 1908) in off-channel habitats such as beaver ponds, oxbows, backwater sloughs, and flooded marshes. These habitats usually have little or no water flow, have silty and organic substrate, and have an abundance of aquatic vegetation and cover for hiding and spawning. In the last 100 years, off-channel habitats have disappeared because of changes in seasonal flows and habitat characteristics resulting from the construction of flood control dams, revetments, channelization, diking, and the drainage of wetlands for bottomland agriculture. This loss of habitat combined with the introduction of non-native species to the Willamette Valley resulted in a restricted distribution and sharp decline in Oregon chub abundance. 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. To evaluate abundance and distribution of Oregon chub populations, the Oregon Department of Fish and Wildlife has conducted surveys since 1991. Information collected also included the presence of non-native and native species, the characteristics of Oregon chub habitats, the characteristics of potential introduction sites, evaluation of Oregon chub introductions, and life history characteristics (Scheerer 2002, Scheerer and McDonald 2003, Scheerer et al. 2006). 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. Thirteen of these populations met the above criteria. 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 (Scheerer et al. 2006). The status of this species has improved substantially over the past decade and with the addition of a single Santiam population, the downlisting criteria will be met (Scheerer et al. 2006).

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Geographic Extent: Willamette River Basin

Status: Final

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Format: PDF File

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Is a physical copy maintained for reference at Headquarters? No