Many studies have examined
relationships between physical stream habitat and distribution
and abundance of anadromous salmonids. It is difficult, however,
to develop strong inferences because anadromous fish spend some
part of their life in a marine environment where they are affected
by a much different array of environmental variables, including
shifts in ocean currents and commercial harvest. In contrast,
salmonids that migrate only in freshwater (potamodromous salmonids,
such as some populations of coastal cutthroat trout [Oncorhynchus
clarki clarki]) are dependent on suitable stream habitats
throughout their lives, and therefore may be more sensitive
to variations in fluvial freshwater habitats than anadromous
salmonids.
Changes in aquatic habitats resulting from land management
activities may be especially relevant for coastal cutthroat
trout. During the last century, the abundance and distribution
of this subspecies have declined across their entire range.
Aquatic habitat degradation, associated with timber harvest,
road building, agriculture, and development,
has been identified as one of the potential causes of their
decline. To date, however, most research concerning coastal
cutthroat trout and their relationships to freshwater habitat
has been conducted on the anadromous life-history type, and
little effort has been expended to describe potamodromous
coastal cutthroat trout populations or linkages with their
aquatic habitat. The purpose of this study is to examine the
relationship of stream habitats and populations of coastal
cutthroat trout across broad spatial scales in western Oregon.
For additional information about this research study see the
CFER
Annual Report. (3.6 MB)
