Record Details

A population study of the rainbow trout (Salmo gairdneri) in a Central Oregon stream

ScholarsArchive at Oregon State University

Field Value
Title A population study of the rainbow trout (Salmo gairdneri) in a Central Oregon stream
Names Osborn, Charles Edwin (creator)
Hall, James D. (advisor)
Date Issued 1967-06-07 (iso8601)
Note Graduation date: 1968
Abstract The rainbow trout population in Elder Creek, Oregon was
studied between June 1965 and November 1966. The physical characteristics
of the stream during the summer season were described.
Rainbow trout were captured in each of three sections on the stream
by electrofishing and were tagged and measured. Population size,
mortality, recruitment, growth rate, and production was estimated
for fish in each section where data were sufficient. Estimates were
made of the yield of trout to the sport fishery.
The water in Elder Creek is relatively low in concentration of
dissolved solids. The stream lies in a canyon of mostly bedrock and
large cobbles with very little spawning gravel. Water temperature
was found to be near the maximum for trout suitability in the lower
reaches of the stream.
Reliable estimates of population size and their variation were
obtained within the summer of 1966. Population size estimates for
the summer of 1965 were not reliable because of the small numbers
of trout that could be obtained during this period. Therefore estimates
of annual rates of mortality, growth, and production were not
possible, Growth rates were estimated for marked and for unmarked
fish during the summer of 1966. Marked fish were found to have a
markedly lower growth than unmarked fish.
Of 755 observations of trout movement during the study less
than four percent were found to have moved more than 300 feet. Immigration
of adult fish into the population was either insignificant or
not detectable.
Although Elder Creek has a good population of legal-sized
native trout, fishing pressure on the stream is relatively light. The
lower reaches are fished more heavily than the headwaters, which
probably receive no angling pressure during some fishing seasons.
Genre Thesis/Dissertation
Topic Rainbow trout
Identifier http://hdl.handle.net/1957/22293

© Western Waters Digital Library - GWLA member projects - Designed by the J. Willard Marriott Library - Hosted by Oregon State University Libraries and Press