Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining associated aquatic and terrestrial communities. The current emphasis on restoring habitat structure-without explicitly considering food webs-has been less successful than hoped in terms of enhancing the status of targeted species and often overlooks important constraints on ecologically effective...
One of the biggest advantages of remote sensing is that large areas of the earth's surface can be surveyed in short periods of time, providing nearsynoptic "pictures." Repeated surveys of one area, like time-lapse photography, can be interpreted as a movie to illustrate the dynamics of detectable features. These attributes...
In this study we present new information on seasonal variation in absolute growth rate in length of coho salmon (Oncorhynchus kisutch) in the ocean off Oregon and Washington, and relate these changes in growth rate to concurrent changes in the spacing of scale circuli. Average spacing of scale circuli and...
Twenty-two steelhead trout (Salmo gairdneri) containing coded wire tags (CWT's) were captured in gillnets fished by the Oshoro-Maru in the Gulf of Alaska and along 180 during 1982-85. These fish originated from North American streams and hatcheries in British Columbia, Idaho, and Washington. One fish was age 0.1, 16 were...
The School of Oceanography, Oregon State University, initiated a study during the spring of 1984 to investigate the utilization of Netarts Bay by juvenile churn salmon. Specific objectives the first year were to determine: 1) the relative numbers of hatchery arid wild churn salmon, 2) the nursery areas utilized by...
The School of Oceanography, Oregon State University, conducted three cruises (May 19-June 2, June 7-22, and September 4-14) in 1982 to study the distribution, abundance, migration, growth and feeding habits of juvenile salmonids during their first summer in the ocean. This is the second year we have had a series...
The School of Oceanography, Oregon State University, conducted three cruises (May 19-June 2, June 7-22, and September 4-14) in 1982 to study the distribution, abundance, migration, growth and feeding habits of juvenile salmonids during their first summer in the ocean. This is the second year we have had a series...
The Oregon State University School of oceanography conducted purse
seining surveys of juvenile salmonids in the ocean off Oregon and Washington
during spring and summer 1981. The objectives of the field study were:
1) To collect information on the distribution and abundance of juvenile
salmonids off Oregon and Washington; and...
A new midwater trawl for sampling deepsea nekton from discrete
depths is described. Its mouth area is about 50 m2. The trawl body is
lined with small mesh netting and terminates in a 5-net opening-closing
codend device. Problems of delayed flushing of animals into the codend
and of entanglement of...
The feeding habits of the Dover sole and rex sole (mainly juveniles) and of slender sole and Pacific sanddab were investigated at seven stations on the continental shelf off central Oregon. Dover sole had a catholic diet, feeding on a large variety of infaunal and epifaunal invertebrates. The composition of...
Demersal fishes were sampled at seven stations located inshore of Heceta Bank, on Oregon's continental shelf, over a 2-yr period with a 3-m beam trawl designed to catch small fiatfishes. Two general assemblages of fishes were recognized: a shallow water 74-102 m), sandy-bottom association where Pacific sanddab, Citharichthys sordidus,was numerically...
This report represents the progress in "Ecological and Radioecological
Studies in the Columbia River Estuary and Adjacent Pacific
Ocean" for the period 1 April 1975 through 31 March 1976. This research
has been supported with funds from the Division of Biomedical and
Environmental Research, U.S. Energy Research and Development Administration...
Pandalis jordani Rathbun, like many other species of pandalid shrimps, undergo regular diel changes in their vertical distribution (Tegelberg and Smith 1957; Alverson et al. 1960; Pearcy 1970, 1972; Robinson in press). Little is known, however, about the vertical distribution and diel migrations of larval and juvenile shrimp, or at...
Catch data for albacore troll boats were collected from fishermen's logbooks and from dockside
interviews during the 1968, 1969, and 1970 seasons. Fishing powers of these boats were calculated and used to determine the 10 most successful and 10 least successful fishermen (highliners and lowliners, respectively) who fished off Oregon...
The progress report that follows includes research results ranging
from unproved ideas to scientific papers published during the tenure of
this contract. The end of the contract year finds several facets of our
work in various states of preparation, therefore the reader is cautioned
that all except the published papers...
A workshop was held in Santa Barbara, California, associated with assessing the populations of nekton animals such as squids, shrimps and fishes. Sessions four major methods of assessing nekton populations:
(1) Net collections
(2) Acoustics
(3) Egg/larval surveys
(4) Visual methods, remote sensing and feeding habit studies
An attempt was...
A total of 19 species of hyperiid amphipods was collected from 1963 to 1967 off Oregon.
Parathemisto pacifica, Paraphronima gracilis, Streetsia challengeri, Tryphana malmi, Hyperia
medusarum, Hyperoche medusarum, and Primno macropa were common. New distributional
records are reported for Scina crassicornis bermudensis and Lanceola loveni. Abundance and
occurrence of common...
The purpose of this study is to examine the hypothesis that diel variations occur in the catches of albacore by boats trolling surface jigs off Oregon. Although albacore fishermen talk of "morning bites" and "evening bites," no published data exist, to our knowledge, confirming these trends.
Studies on the feeding...
This report presents progress accomplished during the 20-month period from 1 July 1972 through 31 March 1974 as part of the program "Ecological Studies of Radioactivity in the Columbia River Estuary and Adjacent Pacific Ocean". This program is a continuing study supported by the Division of Biomedical and Environmental Research...
Gamma-emitting radionuclides were found in benthic fishes from
depths of 50-280O m off the Oregon coast from 1964-1971. 65Zn, 60Co,
54Mn, 144Ce, 137Cs and 40K were present. Zinc-65, originating mainly
from the nuclear reactors on the Columbia River, was the predominant
artifically-induced radionuclide. Levels of 6Zn per g and specific...
Three general types of swimbladders were found in the eight species of myctophids studied: gas-filled, fat-invested, and atrophied or reduced. Small specimens of all species had thin-walled, gas-filled swimbladders. Large specimens of Stenobrachius leucopsarus had fat-invested swim-bladders and large Diaphus theta had either gas-filled or atrophied swimbladders, as found by...
This annual report describes progress in marine radioecological studies
under USAEC Contract Number AT(45-1)2227 Task Agreement 12 during the period
1 July 1970 through 30 June 1971. This contract number replaces USAEC
Contract Number AT(45-1)1750 which started 1 June 1962. Although the basic
report format has not been greatly changed...
This paper reviews some of the distributional features of vertically migrating micronekton off Oregon; describes a new, conducting-cable, midwater-trawl system using an eight-net, opening-closing cod-end unit; and gives some preliminary results on trawl catches relative to sound-scattering layers. A variable complex of organisms, including euphausiids, a sergestid shrimp, and mesopelagic...
Infrared radiometers, photographs, and a multispectral
scanner were used in a remote sensing study of the ocean off
Oregon during the summer of 1969. Upwelling appeared on
infrared temperature maps as a zone of cold water along the
coast and Columbia River water appeared as a warm water
"plume". Sharp...
Sixteen species of oceanic shrimps, seven Penaeidea and nine Caridea, appeared in 244 collections made within the upper 1500 m at one station in the northeast Pacific off Oregon. Most of the species were primarily mesopelagic in distribution. The most abundant species, Sergestes similis, was the only shrimp common in...
Much of our present knowledge about the species composition and distribution of (ephalopods of the Pacific Ocean is derived from collections made on cruises of the "Albatross," steamer of the U.S. Fish Commission, During the late nineteenth and early twentieth centuries. "Albatross" collections along the west coast of North America...
Knowledge of the pelagic organisms in vast areas of the open ocean is very limited. This is particularly true of the small nekton or swimming forms such as fishes, squid, prawns and euphausiids, which are important as intermediate animals in the food chain and are preyed upon by species such...