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...
The effects of three levels of dissolved oxygen (8, 5 and 3 mg/l)
upon the feeding, growth and bioenergetics of juvenile coho salmon,
Oncorhynchus kisutch (Walbaum), were determined in laboratory
studies. Experiments with individual fish were conducted during the
summer, fall and spring to measure rates of food consumption,
standard...
The effects of discharged sewage on physico-chemical conditions
and the distribution and abundance of marine benthic animals were
studied in Shilshole Bay, a part of Puget Sound, off Seattle,
Washington. For over 50 years prior to 1965, when this study was
initiated, 87,300 pounds (32,400 pounds BOD) per day of...
The goal of this study was to better understand stream communities through a perspective that might make their structure, organization, and development more understandable. This goal was approached
through the following objectives:
1. To determine the assemblages of stream organisms and define subsystems within a stream community.
2. To explain...
A framework is presented for a more causal explanation and ordering of stream characteristics than traditional means have used. Patterns of stream habitat distribution are related to particular characteristics of the geomorphology of watersheds. Variability in stream characteristics can be explained by the spatial distribution of properties of the watershed...
Traditional approaches to research and management of striped
bass have tended to be mechanistic, numerically oriented, and
based on limited life history information. In the study
presented here, comprehensive conceptual perspective was used
in a multivariate study of life history and evolutionary
adaptation of 10 striped bass populations representing the...
Atlantic menhaden, compared to gulf menhaden, exhibit
a life history pattern that appears to be adapted to a more
unpredictable reproductive environment. From experiments
on laboratory-reared eggs and larvae, Atlantic menhaden have
larger eggs with larger yolk volume. They are larger at
hatching, utilize their yolk faster, begin feeding at...
A hierarchical classification system of Iceland's
watersheds and rivers is presented. The classification
is based on Iceland's substrate, climate, water, biota,
and human cultural influences. The geological formations
of Iceland are very different in character depending on
their age and formation history. Three major types of
formations occur: Tertiary, Plio-Pleistocene,...
An approach to understanding and managing anadromous salmon, steelhead,
and sea-run cutthroat trout (Oncorhynchus spp.) based on life history and
evolutionary adaptive capacities of species and stocks is presented. Species, stocks,
and local populations are viewed as systems that are continuously adapting to
changing environmental conditions. They have the potential...
Many resource management controversies indicate
disagreement about the possible intended and unintended effects
of management actions on ecosystems. Researchers have
documented a variety of negative effects on specific ecosystems, e.
g. the degradation of salmonid habitat due to mass wasting
(Hagans et al. 1986). While the effects of some management...
Ptychoptera townesi (false crane fly, Diptera) occur in high densities in an experimental stream section that has not been allowed to exceed bankfull flow for more than two decades, but are quite rare in areas both upstream and downstream from this section. By contrast, Paraleptophlebia spp. (mayfly, Epherneroptera) are relatively...
Numerous tests were applied to rainbow trout
of eleven months of age to determine whether
ascorbic acid is an essential element of the diet
of these fish. Although previous work had been
done on this question, conflicts in the results,
the large reliance upon abnormal symptoms such as
lordosis and...
The growth and production of brown trout, Salmo trutta Linnaeus, exposed to a concentration of 0.65 mg/l BOD (4.1 percent by volume) stabilized kraft mill effluent (KME) were studied from October 1973 until May 1974 in three experimental stream channels located near a kraft mill in Albany, Oregon. Growth rate...
Sixteen populations of guppies (Poecilia reticulata) were established
in laboratory aquariums. Eight populations were exposed to
dieldrin at a mean concentration of 0.525 ppb in the water and 2.11
ppm in the food, tubificid worms. Eight populations received control
water and food. All populations were fed three grams of tubificid...
Aquatic communities consisting of guppies, amphipods, copepods, snails, nematodes, rotifers, protozoans, euglenoid flagellates, and other microorganisms were established in sixteen laboratory microcosms. Guppies were exploited at four different levels (0 percent, 10 percent, 20 percent, and 40 percent of the population biomass) with four communities at each level of exploitation....
Organization and the adaptation of aquatic laboratory ecosystems
to resource availability, exploitation, and a toxicant were examined in
a 34-month study. Sixteen 560-liter microcosms including prey,
predator, and competitor populations were employed over a wide range
of energy and habitat resource availability and exploitation of the top
predator. Chronic exposure...
Adequate management and scientific investigation of ecosystems
depends on classification of landscape systems based on all significant
bio-physical and associated cultural properties. The present
classification is a hierarchical systems design that can be modeled in
terms of a natural system interacting with its level-specific
environment. A watershed system in this...
A possible form of a theory of exploitation of fish populations was examined. The exploitation theory was derived from a theory of community dynamics that represents the interactions between populations in a biological community with complex interrelated systems of isoclines on phase planes. The isocline systems are deduced, with a...
Acute toxicity bioassays and growth studies, with juvenile salmon
as test animals, were used to identify and characterize the major
toxic components of a zirconium process effluent (ZPE) produced by
Teledyne Wah Chang Albany Corporation.
The major toxic component of the ZPE is ammonia. Although
other components of the ZPE...
Acute toxicity bioassays (96-hr TL₅₀) were employed to determine
the tolerance of coho salmon (Oncorhynchus kisutch) to inorganic
chloramines at the alevin (yolk sac fry), yolk absorption, and early
juvenile life stages. Any influence of changes in temperature, pH,
and total alkalinity on the tolerance of juvenile coho for chloramines...
In a native prairie of Oregon (363 km²) red-tailed (Buteo jamaicensis), ferruginous (Buteo regalis), and Swainson's hawks (Buteo swainsoni) coexist in one of the highest nesting Buteo densities in North America. In 1979 and 1980, the distribution, density, and productivity of the three species was studied in relation to availability...