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Numerical classification analysis of infaunal composition and distribution on two Oregon coast beachesNunez Dupre, Jose D. 15 December 1978 (has links)
Graduation date: 1979
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Distribution of benthic fishes on the continental shelf and slope of the Oregon coastDay, Donald Stewart 07 July 1967 (has links)
The 36 samples collected with a 22-foot semi-balloon shrimp
trawl at depths from 40 to 1,829 meters off the central coast of
Oregon between July 1961 and June 1962 provided preliminary data
on the distribution, species composition, and associations of benthic
fishes with respect to depth and sediment type.
Sixty-seven species of bottom fishes representing 21 families
were collected; 86 percent of the total number of fishes was composed
of specimens from the families Pleuronectidae, Scorpaenidae,
and Bothidae.
Four communities of benthic fishes were found off the central
Oregon coast within the depth interval from 40 to 1 ,829 meters.
They were characterized by two or three dominant species, depth,
and average sediment type. Ninety-seven percent of the species
occurring in the communities showed high abundance in only one
community. Some species also demonstrated size segregation by
communities.
The total number of species collected in progressively deeper
communities was 26 (42 to 73 meters), 31 (119 to 199 meters), 20
(594 to 1,143 meters), and 9 (1,383 to 1,829 meters). Therefore
the highest number of speciesoccurred in the community on the outer
continental shelf and upper slope, while the lowest number of species
occurred at the extreme depths on the continental slope. The number
of species found on the continental shelf and slope were similar.
Species inhabiting the continental slope, however, usually occurred
over greater depth ranges.
A comparison of the catches of the 22-foot shrimp trawl and a
94-foot fish trawl indicated that the small trawl used in this study
retained comparatively few large fishes or semi-pelagic species.
Fishes of the genus Sebastodes were grossly undersampled and probably
comprised a major portion of the fish population, especially
between the depths of 183 to 547 meters. / Graduation date: 1968
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Diversity and similarity of benthic fauna off OregonStander, Jeffrey M. 15 August 1969 (has links)
Samples of benthic organisms off the coast of Oregon, taken
from depths varying from 50 to 2900 meters, have been analyzed in
terms of diversity at a given station, and similarity and ecological
distance to other stations. Estimates of epifauna abundance were
also made. In the analysis an important distinction is made between
diversity, abundance, and variety indices; the three measures are
considered independent pieces of information relevant to the ecological
structure of the population of interest.
Two types of sampling gear were used. Large epifauna were
sampled with a beam trawl. Polychaetous infauna were sampled with
an anchor-box dredge.
The diversity index chosen is Simpson's index; the measures
of similarity and ecological distance are related. These measures are preferred because of their ease in calculation and basic simplicity.
In addition these measures may be interpreted as estimates of well-defined
population parameters (as Simpson has pointed out) which have
straightforward probabilistic interpretation.
A valid measure of diversity is one piece of relevant information
necessary for elucidating the sufficient parameters of ecological
systems. Therefore the methodology presented has broad application
to studies of population structure. / Graduation date: 1970
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