Oncorhynchus mykiss newberrii
A Klamath basin redband from a small stream in southern Oregon.
The Klamath basin has an odd assemblage of native fish, with the lower portion of the river having species common to other coastal watersheds and the upper portion having species common to Oregon's interior basins. The Klamath basin redband trout were named as the species Salmo newberrii in 1858 for specimens from Upper Klamath Lake and are the only variety of Great Basin redbands to be formally described.
The upper Klamath Basin was once filled with ancient Lake Modoc, which drained when it's outlet cut a channel to the Pacific Ocean via the Klamath River. Today Upper Klamath Lake and Agency Lakes are all that remain of Lake Modoc. Unlike with the other interior redband populations, the Klamath Basin redband has been able to maintain regular use of the lacustrine environment since the last glacial epoch. As such it maintains the largest and most functional adfluvial redband population of any of the interior basins (ODFW 2005). The redbands of the basin exhibit three distinct life history types, adfluvial, fluvial and stream resident, which is typically found in the higher reaches of the basin. According to Behnke (2002) there are genetically two distinct groups of redbands native to the upper Klamath basin, with one that is adapted to lakes and the other to streams. These two groups use different parts of the basin for spawning habitat and thus have been able to avoid hybridization with each other.
Adfuvial individuals in the upper Klamath basin are born in tributaries to Upper Klamath and Agency Lakes and then migrate to the lakes to feed and grow. The lakes are highly alkaline and the Klamath redbands have adapted to survive in these conditions that would be lethal to most trout. Growth in the lakes is rapid due to the fertile environment and the trout may reach sizes up to twenty pounds on a diet of forage fish and invertebrates. Starting in late winter and continuing through spring these fish migrate up the Wood and Williamson Rivers to reach their spawning grounds (Behnke 2002). Klamath basin redbands exhibiting the fluvial life history strategy migrate to the lower portions of the basin's rivers to feed, than migrate to the headwater tributaries to spawn. Many of the streams in the basin are extremely fertile and allow these fish to reach large sizes Stream resident populations are found in the basin's headwater streams and might only travel only a mile or so during their entire lifespan. Due to their smaller living space these fish generally reach a maximum size of around eight inches on a diet composed mainly of aquatic and terrestrial insects.
Although not formally listed under the Endangered Species Act, redband trout of the upper Klamath basin are considered to be at risk of extinction by the Oregon Department of Fish and Wildlife (ODFW). A variety of issues have affected the abundance and distribution of these fish, with the major causes being habitat destruction, construction of dams and the introduction of non-native fish. Interbreeding with hatchery rainbow trout has been an issue in some streams in the basin, and hybridization is apparent in several populations (ODFW 2005). Overall though the Klamath redband genotype still remains intact, especially in Klamath Lake were several factors favor the native trout over introduced rainbow trout. Upper Klamath Lake is a naturally eutrophic body of water and becomes highly alkaline due to algae blooms making it difficult for hatchery fish to survive. Beyond this a salmonid parasite Ceratomyxa shasta is found throughout the basin. The native redbands are resistant to this disease, but it is highly lethal to hatchery rainbow trout (Behnke 1992 and Bartholomew 1998). Brook trout and brown trout have also been stocked in a number of streams in the upper Klamath basin and compete with the native redbands.
Habitat destruction and barriers to migration have also caused many problems for the fish native to the Klamath basin. A major issue has been the alteration of the environment for agricultural purposes. The impacts of land use in the basin have led to a number of affects on the quality of the stream habitat; including channelization, sedimentation and the diversion of water for irrigation (ODFW 2005). Much of the wetlands adjacent to Upper Klamath Lake have been drained for agricultural purposes as well, resulting in both a loss in habitat and increase in the nutrient load added to the lake (Snyder and Morace 1997). While Upper Klamath Lake has likely been eutrophic since before the arrival of Euro-Americans it is now considered to be hypereuptrophic from farming and other activities, which have added increased amounts of nitrogen and phosphorus to the lake. This causes large algae blooms followed by a depletion of oxygen, limiting the fish to creek mouths and spring fed areas of the lake. The impacts of dams on migratory fish have caused major declines in the number of Klamath basin redband trout. Since the completion of the J.C. Boyle Dam in 1959 migratory redband numbers have declined dramatically from 5,529 in 1959 to just 70 passing over the dam in 1991 (Starcevich et al. 2006).
These fish have an olive or even bluish coloration on the back that transitions to a yellowish color across the body. The coloration migratory individuals may be quite silvery and rather similar in appearance to coastal steelhead. Klamath basin redbands typically have a wide pink to brick red stripe along their lateral line, and their gill plates are a rosy or brick red color. The spotting pattern consists of small round or irregular shaped spots that are distributed primarily above the lateral line and on the caudal and dorsal fins. Purplish colored elliptical shaped parr marks are often retained into maturity on stream resident fish but fade on migratory fish. The dorsal fin may be tipped with either orange or white and the lower fins are tipped with white.
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