The use of some age determination methods may result in the
incorrect age structure of fish populations. This in turn may lead
to incorporation of inappropriate data into models used for stock
management. Otoliths are commonly used for determining the age of
fishes, and ages based on the whole otoliths...
Fisheries models are generally built to assess the dynamics of a resource with a given fishing mortality
which level can be decided by some “decision maker” and/or which can be an observed process, e.g. times series proportional to some observed values of fishing effort. In these cases, the resource dynamics...
Discusses the removal of boulders in the Alsea River near Tidewater by blasting with dynamite. Documents the number of fish killed. Includes a copy of the blasting permit.
Published December 1908. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
An increase in frequency and severity of hot, dry summers has been associated with a dramatic shift in the coniferous forests of western Oregon’s valleys, especially on the privately-owned properties along the low-elevation edges of these valleys. Various conifer species, including Douglas-fir (Pseudotsuga menziesii), are declining in these forests, leaving...
An experiment was conducted to compare the reproductive
performance and serum concentrations of progesterone and estrogen of
mated first (n=18) and third (n=18) estrous gilts slaughtered in equal
numbers on days 3, 15 and 30 postmating. Fertilization rate did not
differ between mated first and third estrous gilts. Embryonic survival...
"We monitored oyster mortality in Yaquina, Coos, and Tillamook bays from July 1966-March 1972. Pacific oyster (Crassostrea gigas) mortality in Yaquina Bay appears to be lower than in any other reporting area on the Pacific Coast, generally less than 2% per year. Native oyster (Ostrea lurida) mortality ranged from 9.6-28.2%....
"Objectives of Oregon's Oyster Mortality study for the year ending March 1969 were similar to those of the first 2 years of the program: (1) to monitor oyster mortality in Yaquina, Tillamook and Coos bays, (2) to collect hydrographic data in Yaquina Bay and (3) to furnish oysters to the...
"Objectives of Oregon's Oyster Mortality Study from July 1, 1967-March 31, 1968, were: (1) to monitor oyster mortalities to detect a possible increase in mortality rate, (2) to collect hydrographic data for comparison with data from areas where high oyster mortalities occur, and (3) to furnish oysters from a relatively...
"Oyster mortality data collected from suspended trays at three subtidal locations in Yaquina Bay disclosed an unusually high 26.5% Pacific oyster (Crassostrea gigas) mortality during the study year. Almost all of this mortality resulted from culling damage which occurred previous to introduction of the oysters into trays. Native oyster mortality...
Covers: April 1, 1969 - March 30, 1970. "Objectives of Oregon's oyster mortality study for the past year included monitoring oyster mortality in Yaquina, Tillamook, and Coos bays, obtaining hydrographic data in Yaquina Bay; and furnishing oysters to the University of Washington and the Bureau of Commercial Fisheries (BCF) in...
"Although Oregon has been relatively free from any major oyster mortality a monitoring program has been established with the basic objectives being to: (1) monitor mortalities; (2) collect environmental data; and (3) furnish oyster from a disease-free area for histological examination." (Introduction) Includes hydrographic data from test plots in Yaquina,...
This document is a summary of the March 1968 meeting to determine the cause of an oyster mortality incident. It answers several questions about criteria for establishing the causative organism and discusses programs for studying oyster mortalities.
Educational poster of invasive Koi fish. The spread of these fish is often traced to pet owners who release them into wild habitats when they no longer want to care for them. The poster is on display at Hatfield Marine Science Center Visitor Center is Newport, Oregon.
Bluegill sunfish, Lepomia macrochirus, and cutthroat trout,
Salmo clarki, were exposed to a rapidly declining oxygen tension
for a period of time sufficient to just cause loss of equilibrium in
the fish. During recovery from the stress, measurements of
oxygen uptake, blood lactic acid, blood glucose, liver glycogen,
muscle glycogen,...