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 capacity to evolve in
different ways in different environments through both life history and evolutionary
adaptation. Habitat organization forms a template for genus, species, stock, and
local population life history organization. Harvesting, habitat alteration resulting
from land use practices and other human activities can alter the organization and
adaptive capacities of species and stocks, and thus their long term persistence.
The adaptive capacity of Oncorhynchus relative to its habitat and management
environment is examined at the species, stock, and local population levels. Life
history characteristics of representative stocks and local populations are analyzed
using Detrended Correspondence Analysis (DECORANA). Fresh water migration
distance and latitude are used to "explain" ordination patterns of Oncorhynchus
species in the North Pacific Basin. Fresh water migration difficulty and mean annual
runoff are used to interpret life history patterns of Columbia Basin chinook salmon
stocks. Upstream migration difficulty and fall water temperatures are used to explain
the ordination patterns of local populations of Willamette spring chinook salmon.
Fishery management practices are examined in terms of their impacts on the
organization and adaptive capacity of species, stocks, and local populations of
Oncorhynchus.
Management generalizations and guidelines derived from the life history
theory are applied to management of Willamette spring chinook salmon. Maintaining
habitat changes in the Willamette Basin within the historic range of fluctuations will
tend to maximize co-organization of local populations. Management activities should
provide relatively constant habitat and fishery conditions for natural selection
processes to "organize" life history traits over a period of at least a few generations.
Fisheries should selectively harvest local populations that show a high degree of
realization of their adaptive capacity. By focusing instead on maximizing the co-organization
of stocks, their habitat and fishery environments, and protecting the
adaptive capacities of stocks, we will go a long way toward providing long-term
sustainability for social communities dependent on fisheries. / Graduation date: 1994
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35699 |
| Date | 11 June 1993 |
| Creators | Wevers, Mary Jo |
| Contributors | Warren, Charles E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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