A theoretical framework for economic fishery management was
developed. Extensive isocline analysis of a general fishery model
yielded a detailed look at the possible equilibrium behavior of a
system that was allowed to vary in terms of the levels of its
environmental parameters, its composition, and the response functions
governing...
Laboratory stream communities in simulated old growth second
order streams were sampled June 1984 and June 1985 to advance an
understanding of their organization and development, and their
response to an environmental perturbance, the toxicant dieldrin. An
interpenetrating hierarchical view of habitats and community
subsystems was taken to conceptualize community...
A generalized mathematical model of ecosystems is
developed. The model begins with the general class of
systems known as state-determined systems, in which the
time-derivative of each state variable is a function of some
subset of the set of all system state variables and
.environmental parameters. A formal basis is...
To understand the influence of selective harvesting on
the adaptive capacity of fish populations in changing
environments, a computer simulation model was developed. In
the model, hypothetical populations were composed of five
different life histories, which were genetically determined.
Each life history type had its own rate of survival and...
The purpose of this research was to examine the
effects of fishing on life history parameters of the spiny
lobster, Panulirus homarus. The study areas selected had
different levels of fishing pressure but relatively similar
habitats. The lowest fishing effort was found in Hadbin
while the highest fishing effort was...
The eastern margin of the Eastern North Pacific Ocean
was classified into physiographic regions based on a suite
of physical characteristics. Information on cultural and
biological characteristics of this area was meshed with this
classification. The result was a classification of the
Eastern North Pacific into natural-cultural systems whose
boundaries...
The research involved development of two ecological
simulation models to explain the complex dimensionality of
chinook salmon (Oncorhynchus tshawytscha) life history
structure (represented by the age composition of the
spawning stock) and management difficulties entailed in the
complexity.
Since different sizes of chinook salmon are thought to
adapt differently to...
As part of a hierarchical approach to classifying watersheds and stream habitats based on geomorphic and geologic criteria, we defined ten classes of fluvial and lacustrine habitats at the scale of valley segments. Valley segments are landscape units which encompass surface waters and the adjacent floodplains and hillslopes with which...
Although nearshore macroinvertebrates are integral members of high
mountain lentic systems, knowledge of ecological factors influencing their
distributions is limited. Factors affecting distributions of nearshore
macroinvertebrates were investigated, including microhabitat use and
vertebrate predation, in the oligotrophic lakes of North Cascades National
Park Service Complex, Washington, USA, and the conformity...
The restoration of rivers and streams should be based on a
strong conceptual framework. Streams are developing systems. As
such, streams exhibit temporal behaviors that change with changing
stream environments. Underlying the dynamic development of streams is
potential capacity. Streams express this capacity as an array of
habitats over time...