Distribution and Status of Seven Native Salmonids in the Interior Columbia River Basin and Portions of the Klamath River and Great Basins

Document Details:

Title: Distribution and Status of Seven Native Salmonids in the Interior Columbia River Basin and Portions of the Klamath River and Great Basins
Category: Technical Report
File: Thurow-et-al_1997_0378_Distribution-of-native-salmonids-in-the-Klamath-River.pdf
Updated Date: 21.06.2017
Author(s)/Source(s): Russell F. Thurow , Danny C. Lee, Bruce E. Rieman
Publication Date: 1997
Focal Topic: Salmon
Location: Klamath Basin
Watershed Code: 180102
Abstract:

We summarized presence, absence, current status, and potential historical distribution of seven native salmonid taxa—bull trout Salvelinus conjluentus, Yellowstone cutthroat trout Oncorhyncus clarki bouvieri. westslope cutthroat trout O. c. lewisi, redband trout and steelhead ,stream type (age-1 migrant) chinook salmon and ocean type (age-0 migrant) chinook salmon—in the interior Columbia River basin and portions of the Klamath River and Great basins. Potential historical range was defined as the likely distribution in the study area prior to European settlement. Data were compiled from existing sources and surveys completed by more than 150 biologists. Within the potential range of polamodromous salmonids, status was unknown in 38-69% of the area, and the distribution of anadromous salmonids was unknown in 12-l5%. We developed models to quantitatively explore relationships among fish status and distribution, the biophysical environment, and land management, and used the models to predict the presence of taxa in unsampled areas. The composition, distribution, and status of fishes within the study area is very different than it was historically. Although several of the salmonid taxa are distributed throughout most of their potential range, declines in abundance and distribution and fragmentation into smaller patches are apparent for all forms. None of the salmonid taxa have known or predicted strong populations in more than 22% of their potential ranges, with the exception of Yellowstone cutthroat trout. Both forms of chinook salmon are absent from more than 70% and steelhead from more than 50% of their potential ranges, and all are approaching extirpation in portions of their remaining ranges.

Keyword Tags:
Bull Trout, Salvelinus confluentus,