California bighorn sheep (Ovis canadensis californiana) were studied on Hart Mountain, Oregon, during the summer and fall of 1976, and the spring of 1977. The population consisted of a minimum of 196 sheep in June, 1977. The high number of lambs observed and high lamb:ewe ratios throughout both years of...
From July 1985 to April 1987 the pelagic zooplankton community of Crater Lake, Oregon was studied to determine taxonomic structure, absolute and relative densities, and spatial and temporal distributional patterns. Samples were collected using vertically-towed zooplankton nets. The community structure consisted of two cladoceran and nine rotifer species, which were...
One of the biggest hurdles for a juvenile salmonid (Oncorhynchus mykiss) is migrating downstream from freshwater spawning grounds to the ocean. Juveniles from wild broodstock were reared from the South Santiam River for more than 1 year at the Oregon Hatchery Research Center (OHRC) in Alsea, OR. The fish were...
Despite being a highly charismatic and frequently exhibited organism,
Giant Pacific Octopus (Enteroctopus dofleini) population dynamics
are poorly understood. Basic monitoring data for this species is
limited to bycatch and stomach contents of other fisheries species. An
essential step to a better estimation of population size and
productivity is to...
An exploratory study of 48-hour Pacific oyster embryo
bioassays employing spent sulfite liquor (SSL) in test
concentrations ranging from 10 to 45 ppm was made at two
incubation temperatures, 20° and 24° C. Fourteen separate
bioassays, each employing embryos originating from three to
four different parentages, were conducted at the...
A study of the population ecology of Columbia River fall chinook
salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt
to determine the cause of a serious decline in this run which occurred
in the early 1950's. Fluctuations in abundance of major salmon runs
the North Pacific were examined to...
The acute toxicity of Diquat (1:1-ethylene-2:2' dipyridylium
dibromide) and Dichlobenil (2, 6-dichlorobenzonitrile) to six selected
pond invertebrates was determined using the median tolerance limit
estimation method. Diquat was more toxic to the amphipod, Hyalella
azeteca than to the aquatic insects Callibaetis, Limnephilus,
Enallagma, Libellula, and Tendipedidae. The addition of mud...
The fatty acids of coho salmon were identified and then a study
was conducted to determine the effects of exercise on the fatty acids
of salmon forced to swim against water velocities of 52, 54, 56, and
59 cm/sec, The shorter and lighter salmon were less competent at
a given...
The fishes of Upper Klamath Lake appeared to distribute
themselves in three general groups during the summers of 1964
and 1965: (1) the chubs--unrestricted as to distribution with slight
seasonal variations; (2) rainbow trout and yellow perch -- restricted
to certain water conditions that exist only along the northern marsh...
The effects of sublethal concentrations of kraft mill effluents
(KME) on the growth, food consumption, and swimming ability of
juvenile chinook salmon, Oncorhynchus tschawytscha (Walbaum),
were studied from February 1966 to May, 1967.
The KME used in these studies was obtained from two pulp and
paper mills producing paper from...
The black crappie was evaluated as a pond fish in four experimental
ponds in the Willamette Valley. Two ponds were stocked with
largemouth bass, bluegill sunfish, and black crappie (1:9:3), and
two ponds with largemouth bass and black crappie (1:3).
Total biomass was greatest in the three-species ponds (80 kg/...
Of 149 wild animals from two western Oregon river drainage
areas and other localities in which "salmon poisoning" disease (SPD)
is enzootic, including ten mammalian and two avian species, 79
harbored Nanophyetus salmincola, the SPD vector. The shorttail
weasel, Mustela erminea; river otter, Lutra canadensis; spotted
skunk, Spilogale putorius; Norway...
The individual stocks of sockeye salmon that make up the
annual spawning migration to the Bristol Bay region of Western
Alaska are produced in the lakes and streams of ten major river
systems, which discharge into the bay over a shoreline distance of
120 miles. The hypothesis adopted in this...
Reproductive characteristics of introduced eastern cottontail
rabbits, Sylvilagus floridanus (J. A. Allen), were determined from
486 rabbits collected between January 1, 1968 and June 30, 1969,
near Corvallis, Oregon.
Sex ratios were 1:1 for all rabbits collected and for all embryos
20 days or more gestation. On the basis of...
This thesis reports the results of a study on the influence of biologically
stabilized kraft mill effluent (SKME) on the food relations and
production of juvenile chinook salmon, Oncorhynchus tschawytscha
(Walbaum), in laboratory streams. Experiments were conducted at
the Oak Creek Fisheries Research Laboratory, Oregon State University,
during 1967 and...
A study of the distribution, relative abundance and diet of
fishes sympatric with juvenile sockeye salmon, Oncorhynchus nerka
(Walbaum), within the freshwater nursery areas of the Naknek River
system was undertaken from 1961 to 1963. The study was part of an
extensive investigation to determine what factors in the freshwater...
Descriptions and distributions are given of 28 species of
Liparidae occurring or possibly occurring below 200 m between San
Francisco and northern Vancouver Island, with keys for their identifications.
Nine genera are included: Careproctus, Elassodiscus,
Lipariscus, Nectoliparis, Rhinoliparis, Acantholiparis, Paraliparis,
and two new genera are described, Odontoliparis and Osteodiscus.
Eight...
Blackside dace, Rhinichthys osculus nubilus (GIRARD), were
collected from ten western Oregon streams and examined for variation
among morphological and meristic characters. Several characters were
observed to vary between populations studied. Number of vertebrae,
number of scales in and above the lateral line, length of snout, and
depth of body...
One means of evaluating the temperature requirements of an
animal is to determine changes temperature causes in the uses and
losses of energy and materials in the food the animal consumes. To
develop energy budgets for cichlids (Cichlasoma bimaculatum) at different
temperatures (20, 24, 28, 32 and 36 C) data...