This paper shows how ten easy-to-use linear skyline thinning production rate equations were obtained by transforming existing but more cumbersome turn time equations using the THIN simulation model [11). The equations provide reasonable approximations of delay-free hourly production for several cable yarders operating skyline thinnings under a variety of conditions....
In ocean fisheries for Pacific salmon Oncorhynchus spp., there can be several forms
of gear-related mortality. Much research effort has been directed at estimating mortality rates for salmon that are hooked and then released. Also potentially important but not easily measured is mortality of fish that escape from the hook...
Better fisheries management is often given as one justification for research on improving forecasts of fish survival. However, the value gained from expected improvements in forecast skill in terms of achieving management goals is rarely quantified as part of research objectives. Using Monte Carlo simulations of population dynamics, we assessed...
Generalized additive models (GAMs) were used to investigate the relationships between annual recruitment of natural coho salmon (Oncorhynchus kisutch) from Oregon coastal rivers and indices of the physical ocean environment. Nine indices were examined, ranging from large-scale ocean indicators, e.g., Pacific Decadal Oscillation (PDO), to indicators of the local ecosystem...
Understanding seasonal migration and localized persistence of populations is critical for effective species harvest and conservation management. Pacific salmon (genus Oncorhynchus) forecasting models predict stock composition, abundance, and distribution during annual assessments of proposed fisheries impacts. Most models, however, fail to account for the influence of biophysical factors on year-to-year...
Managing weak stocks in mixed-stock fisheries often relies on proxies derived from data-rich indicator stocks, although there have been limited tests of the appropriateness of such proxies. For example, full cohort reconstruction of tagged Klamath River fall-run Chinook Salmon Oncorhynchus tshawytscha of northern California enables the use of detailed models...