All animals that interact with fishing gear are not necessarily captured, and all animals that are captured are not necessarily retained. Fishing practices and gear configuration, management regulations, and markets dictate which animals ultimately are retained or discarded. The impact of a fishery and the efficacy of management regulations can...
:
_____________________________________________________________________
DavidB. Sampson
All animals that interact with fishing gear are not necessarily captured
Sampling error associated with estimates of species composition and age composition
of commercial groundfish landings in Oregon from 1989 to 1991 is documented to evaluate
the impact of variable landing data on fisheries management and monitoring programs. The
statistical reliability and bias associated with two multistage sampling designs are
investigated...
Co-management is considered an alternative approach to fisheries management,
however, not all co-managed fisheries have been successful. Most studies discussing the
success and failure of co-management have emphasized economic and social attributes of
success and failure, such as fishery rights and institutional arrangements. The effect on
co-management of biological characteristics,...
Sardines and anchovies are small pelagic fishes that support important commercial fisheries around the world. This project reviews the inverse cyclic behavior in the abundance of these two stocks, which is a striking feature in many regions. In addition, the project used qualitative loop analysis techniques to analyze the feasible...
Stock assessments for many U.S. Pacific coast groundfish stocks are developed using the catch-at-age method known as Stock Synthesis. In this work a simulation package was developed and used to evaluate the sensitivity of the Stock Synthesis program. More specifically, the evaluation focused on the impacts of input data errors...
Marine fish are subject to direct and indirect oceanographic variations operating at short and long time scales. In this study feeding habits and long-term growth condition of several groundfish species of the Pacific Northwest are examined to understand the relationship between variations in the fish's biological and life history components...
Salmonid run sizes are strongly affected by their early marine stage. Fully understanding the life history of salmonids means understanding how they interact with their marine environment and with other fishes. Changes in the biological and physical environment off the Columbia River region affects the distribution and abundance of predatory...
Twenty-three bottom-trawl fish assemblages were identified from the relative biomass of
33 dominant species that occurred in the National Marine Fisheries Services' triennial
trawl surveys over the continental shelf and upper slope off California, Oregon, and
Washington from 1977 to 1992. The assemblages accounted for about 70% of the total...
The spawning habitat associated with fall chinook salmon (Oncorhynchus
tshawytscha) redd clusters was investigated in the Hanford Reach of the Columbia River.
A conceptual spawning habitat model is proposed that describes how geomorphic
features of river channels create hydraulic processes, including hyporheic flows, that
influence where salmon spawn in unconstrained...
Field experiments were established in 1982 and 1983 on a Woodburn silt loam soil (Aquultic Argixeroll) to examine the effect of S fertilizer on dinitrogen fixation and dry matter yield of 10 week-old seedling alfalfa (Medicago sativa L. cv. 'Apollo'). Six levels of S fertilizer (0 to 67.2 kg S/ha)...
