The Oregon chub. Oregonichthys crameri. one of Oregon's endemic freshwater fishes. is restricted to the Willamette and Umpqua rivers and their tributaries. Specimens from the two rivers have traditionally been considered the same species. The goal of this study was to re-examine that assumption and determine if the Willamette Oregon chub and the Umpqua Oregon chub represent different taxa. The Oregon chub were examined through three sets of data: meristic. morphometric. and electrophoretic. Univariate (General Linear Model) and multivariate (Principal Components Analysis and Discriminant Function Analysis) analyses were performed. Univariate analyses resulted in significant differences between the Willamette and the Umpqua in the meristic characters: precaudal vertebrae. caudal vertebrae. the difference between precaudal and caudal vertebrae. pelvic fin rays, rudimentary dorsal rays, total dorsal rays, upper procurrent caudal rays, total caudal rays, maxillary barbels, and cephalic lateral line counts; in the morphometric characters: body width, head depth, eye length, and anal base length; and in the electrophoretic character, lactate dehydrogenase in muscle tissue. Discriminant function analysis based on meristic characters correctly classifies 90% of the Willamette and 65% of the Umpqua specimens. Discriminant function analysis based on morphometric characters correctly classifies over 89% of the Willamette and over 84% of the Umpqua specimens. Descriptions of the Willamette and Umpqua Oregon chub subspecies are given.

Once historically widespread throughout the Willamette and Umpqua River drainages, the Willamette Oregon chub is now restricted to scattered populations along 15 miles of the Middle Fork of the Willamette River whereas the Umpqua Oregon chub is still widely distributed. The decline in the Willamette drainage was more severe because changes in the physical and biological habitat were more severe when compared to the Umpqua drainage. The Willamette Oregon chub may be more sensitive to environmental degradations than the Umpqua Oregon chub. The difference in sensitivity to degradation is a result of ecological differences between Willamette and Umpqua Oregon chub. Willamette Oregon chub inhabited areas with primarily very little if any current, fed in the water column, and spawned in aquatic vegetation. Umpqua Oregon chub inhabited areas with primarily slow water velocities, fed on benthic prey, and spawned over gravel substrate. Because Willamette Oregon chub inhabit slackwater habitats they may be more sensitive to water velocity increases and exotic species, whereas Umpqua Oregon chub have a habitat refuge in relatively faster water velocity habitats. Willamette Oregon chub larval stages are described and illustrated. The following combination of characters distinguish Willamette Oregon chub larvae from other cyprinid larvae found in the Willamette drainage: 33-37 myomeres, preanal length of 52-61%, and absence of snout pigment. Willamette Oregon chub larvae generally congregated in nearshore areas, in the upper layers of the water column, in shallow water. They fed primarily in the water column, and ate primarily rotifers and cladocerans.

Endangered and Threatened Wildlife and Plants - Oregon Chub - Removal From the List of Endangered and Threatened Wildlife (US Fish and Wildlife Service Regulation) (FWS) (2018 Edition) The Law Library presents the complete text of the Endangered and Threatened Wildlife and Plants - Oregon Chub - Removal From the List of Endangered and Threatened Wildlife (US Fish and Wildlife Service Regulation) (FWS) (2018 Edition). Updated as of May 29, 2018 We, the U.S. Fish and Wildlife Service (Service), are removing the Oregon chub (Oregonichthys crameri) from the Federal List of Endangered and Threatened Wildlife. This determination is based on a thorough review of the best available scientific and commercial information, which indicates that the Oregon chub has recovered and no longer meets the definition of an endangered species or a threatened species under the Endangered Species Act of 1973, as amended (Act). Our review of the status of this species shows that the threats to this species have been eliminated or reduced and populations are stable so that the species is not currently, and is not likely to again become, a threatened species within the foreseeable future in all or a significant portion of its range. This rule also removes the currently designated critical habitat for the Oregon chub throughout its range. This book contains: - The complete text of the Endangered and Threatened Wildlife and Plants - Oregon Chub - Removal From the List of Endangered and Threatened Wildlife (US Fish and Wildlife Service Regulation) (FWS) (2018 Edition) - A table of contents with the page number of each section

Endangered and Threatened Wildlife and Plants - Reclassification of the Oregon Chub From Endangered to Threatened (US Fish and Wildlife Service Regulation) (FWS) (2018 Edition) The Law Library presents the complete text of the Endangered and Threatened Wildlife and Plants - Reclassification of the Oregon Chub From Endangered to Threatened (US Fish and Wildlife Service Regulation) (FWS) (2018 Edition). Updated as of May 29, 2018 We, the U.S. Fish and Wildlife Service (Service), are reclassifying the federally endangered Oregon chub (Oregonichthys crameri) to threatened status under the authority of the Endangered Species Act of 1973, as amended (Act). This decision is based on a thorough review of the best available scientific and commercial data, which indicate that the species' status has improved to the point that the Oregon chub is not currently in danger of extinction throughout all or a significant portion of its range. This book contains: - The complete text of the Endangered and Threatened Wildlife and Plants - Reclassification of the Oregon Chub From Endangered to Threatened (US Fish and Wildlife Service Regulation) (FWS) (2018 Edition) - A table of contents with the page number of each section