Harney-Malheur Basin Redband

Oncorhynchus mykiss newberrii

Native Trout Fly Fishing

A Harney-Malheur basin redband from an eastern Oregon desert stream

Introduction

The Harney-Malheur Basin redband trout are native to streams flowing into Harney and Malheur lakes in eastern Oregon. These fish are considered to be part of the subspecies Oncorhynchus mykiss newberrii,and are thought to have derived from Columbia Basin redband trout when a lava flow isolated the basin from the Malheur River drainage 8,000 to 10,000 years ago (Behnke 1992).

Life History Information

Harney-Malheur basin redband trout exhibit many life history traits common to other subspecies of rainbow trout. These redbands exhibit stream-resident, adfluvial and fluvial life history patterns. As with much of the desert redband habitat, the streams in the Harney-Malheur basin are generally small, unstable and often lack interconnectedness to each other. Due to this most of the streams in the basin have fish exhibiting a stream-resident life history type. Rodnick et al. (2004) showed that for trout from stream resident populations in the Harney-Malheur basin and Catlow Valley, the maximum feeding and growth rates occur at higher temperatures than with any other forms of rainbow trout. This unique trait arises from the harsh conditions that these fish have been faced with over the last several thousand years.

The Donner und Blitzen River drainage is the only drainage within the basin that maintains suitable conditions for trout to survive in throughout its entire length and as such its' fish are able to exhibit a migratory life history strategy (ODFW 2005). With this life history type the fish migrate to the lower reaches of the river or Malheur Lake to forage. The fluvial portion of this life history in which fish travel to Malheur Lake, is only possible when the lake level is high enough, and during drought years the lake may desiccate to the point at which the habitat is not suitable for trout. This flexibility to take advantage of increased foraging opportunities when conditions allow has been important adaptation to insuring the survival of these fish in such a harsh environment (Behnke 2003). The fish exhibiting these migratory life histories migrate to the upper river and its tributaries to spawn between March and June, with the peak migration timing occurring just after spring runoff begins to subside in April and May (Anderson 2007).

Status

In 1997 there was a petition to list the redbands of the desert basins of Oregon including the Harney-Malheur redband under the Endangered Species Act (ESA) (USFWS 1997). Although it was found that these fish were not warranted to be listed under the ESA, the Oregon Department of Fish and Wildlife followed up with a survey of the status of these fish. Of the ten populations identified in the survey, two appeared to be severely depressed, and only the Donner und Blitzen drainage was not suffering from low productivity (ODFW 2005). The main threats to these fish have come from habitat degradation and the introduction of non-native fish. Throughout their native range habitat has been altered by the removal of riparian vegetation, presence of man-made barriers to migration and reduced stream flows. Up until 1993, rainbow trout were stocked in streams throughout the Harney-Malheur basin and redbands in the Silvies River and one other population appear to be slightly hybridized with hatchery origin rainbow trout (ODFW 2005).

Description

Harney-Malheur basin redband trout are similar in appearance to Columbia Basin redband. The coloration of these fish is olive on the back and transitions to yellowish green across the body. These redbands have a pink to brick red stripe along their lateral line, and the same coloration on their gill plates. The spotting pattern consists of small round to irregular shaped spots profusely distributed both above and below the lateral line, and on the caudal and dorsal fins. The caudal fin is forked, and the dorsal, anal and pelvic fins are tipped with white.

Stream Resident Form

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Native Trout Fly Fishing
Native Trout Fly Fishing
Native Trout Fly Fishing
Native Trout Fly Fishing

 

Native Range

Native Trout Fly Fishing

A map of the native range of the Harney-Malheur Basin redband trout. Data Sources: Behnke (2002) and ODFW (2005).