K.F. Tiffan

40 items:

Osmoregulatory performance and marking of subyearling Chinook salmon at McNary Dam to estimate adult contribution. Annual report 1993 No abstract available Categories: Publication; Types: Citation
Quantifying flow-dependent changes in subyearling fall chinook salmon rearing habitat using two-dimensional spatially explicit modeling We used an analysis based on a geographic information system (GIS) to determine the amount of rearing habitat and stranding area for subyearling fall chinook salmon Oncorhynchus tshawytscha in the Hanford Reach of the Columbia River at steady-state flows ranging from 1,416 to 11,328 m3/s. High-resolution river channel bathymetry was used in conjunction with a two-dimensional hydrodynamic model to estimate water velocities, depths, and lateral slopes throughout our 33-km study area. To relate the probability of fish presence in nearshore habitats to measures of physical habitat, we developed a logistic regression model from point electrofishing data. We only considered variables that were compatible with a GIS and... Categories: Publication; Types: Citation; Tags: North American Journal of Fisheries Management
Comparison of subyearling fall chinook salmon's use of riprap revetments and unaltered habitats in Lake Wallula of the Columbia river Subyearling fall chinook salmon's Oncorhynchus tshawytscha use of unaltered and riprap habitats in Lake Wallula of the Columbia River was determined with point abundance data collected by electrofishing in May 1994 and 1995. We documented the presence or absence of subyearlings at 277 sample sites and collected physical habitat information at each site. Based on logistic regression, we found that the probability of fish presence was greater in unaltered shoreline habitats than in riprap habitats. Substrate size was the most important factor in determining fish presence, with dominant substrates larger than 256 mm having the lowest probability of fish presence. Water velocity, also included in our model due to its... Categories: Publication; Types: Citation; Tags: North American Journal of Fisheries Management
Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook salmon. Juvenile American shad were abundant and represented over 98% of the trawl catch in late summer. The five major taxa collected in zooplankton tows were Bosmina longirostris, Daphnia, cyclopoid cope-pods, rotifers, and calanoid copepods. We evaluated total crustacean zooplankton abundance and Daphnia biomass in... Categories: Publication; Types: Citation; Tags: Northwest Science
Effects of summer flow augmentation on the migratory behavior and survival of juvenile Snake River fall Chinook salmon. Annual report 2002 Abstract not available Categories: Publication; Types: Citation

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