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...
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 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...
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...
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...
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...
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...
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...
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...
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...
Dover and rex sole larvae attain an exceptionally large size and have a long pelagic life. Dover sole larvae (9-65 mm standard length) were collected in mid-water trawls and plankton nets during all months of the year. Judging from growth of larvae and occurrence in bottom trawls of recently metamorphosed...
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...
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 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...
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...
During July 1970, albacore boats trolling surface jigs (jig boats) had record catches in an area off the mouth of the Columbia River. The jig fishery declined suddenly in late July and was poor throughout the remainder of the summer. No obvious oceanographic changes were correlated with these drastic changes...
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...