Chapter 1, a dichotomous key for the identification of nine salmonids of the Inland Northwest using six diagnostic skull bones; and associated equations to estimate total length and weight form bones ingested by piscivores or found in archeological sites; Chapter 2, Utilization of acoustic biotelemetry to define the movements of Lake Roosevelt Redband trout, oncorhynchus mykiss gairdneri
Date of Award
Master of Science (MS) in Biology
"The fish skull is a complex anatomical structure, comprised of numerous bones that are often unique to the fish's genera or species. These unique qualities allow researchers to use bone to identify and quantify fish in piscivore and archeological investigations. Due to the high degree of similarity among skull bones of salmonids, adequate descriptions for keying out most salmoinds is limited in the available literature. To address this, eight different bones from a sample of 273 fish, representing nine salmonid species, were observed and measured. Observations and measurements were used to construct dichotomous keys and regression models for identifying and quantifying each the nine salmonids when a single bone is present. Of the eight bones, the premaxillary, maxillary, dentary, cleithra, preopercle and opercle displayed species specific qualities for all nine species. These unique qualities have been used to construct a dichotomous key. The remaining two bones, the pharyngeal arch and vertebra, were not different enough to key out these bones from each species. All eight bones provided a precise single or multilinear regression model usable to back calculate fish total length from the length of a single bone"--Leaf 2.;"The upper Columbia River Basin once produced annual runs of 1 to 3 million salmon and steelhead (8-12% of Columbia River run; UCUT 1985) and provided habitat for lamprey, sturgeon and other fish species. Today, resident redband rainbow trout and kokanee salmon, potential remnant populations of anadromous runs, remain in Lake Roosevelt. To better understand how naturally occurring redband rainbow trout currently use the reservoir, 51 acoustic tags were surgically implanted into wild Lake Roosevelt redband rainbow trout across several size classes (155-616mTL) in 2013. Tagging efforts were divided across five tributary groups, to infer whether each stock utilizes the reservoir in a distinctive pattern, or if they all rely upon key areas. Condition factor for all redbands averaged at 0.878 (SD, 0.121), with no statistical difference among tributary groups. The movements, generalized distribution, and entrainment rates of redbands were passively monitored between April and August, using 61 acoustic receivers permanently moored in the Sanpoil and Spokane Rivers and across 263km of the mainstem Columbia from Rufus Woods Lake to Huge Keenleyside Dam, British Columbia. Monthly kernel density plots were constructed to provide visual representations of fish movement and occupancy across the reservoir. Minimum displacement per hour (MDPH) was calculated and associated with daily values for reservoir elevation, inflow, discharge, water retention time, and temperature collected from the forebay at Grand Coulee Dam to asses the effects of reservoir operation on redband movement. Though there was a small amount of overlap between the tributary groups, we observed a general trend for tributary groups to reside in distinctive areas. Alder Creek redbands (n=5) ranged across the largest portion of the reservoir, Burbot Creek to Kettle Falls, but were most frequently found between Hunters and Castle Rock. Big Sheep Creek redbands (n=14) generally remained between the Little Dalles Eddy and Big Sheep Creek, with a number of fish remaining exclusively in this zone through August. Outside of this area, Big Sheep redbands were found from the international border to Bis-sell Island. Sanpoil redbands utilized the lower reservoir, particularly Spring Canyon, more than any other tributary group, however, they were most frequently found to remain in the Sanpoil and Keller Ferry region, with some fish remaining exclusively in this area through August. Only five of the total Spokane River redbands (n=13) left the Spokane River during this study. Of these five redbands, three ranged downstream to Spring Canyon, and two ranged upstream of Hunters. Redbands from Big Sheep Creek were the only group that displayed a marginal amount of correlation between MDPH and reservoir inflow (rÂ²=0.122, p<0.001), discharge (rÂ²=0.087, p<0.001), water retention time (rÂ²=0.052, p=0.003), and temperature (rÂ²=0.061, p=0.002). Sanpoil River redbands were the only group that lost tagged fish due to entrainment (n=3). All entrained fish were large (386-521mm TL) adults that left the reservoir between May and July 2013"--Leaf 133.
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Stroud, Aaron and Scholz, Allan T., "Chapter 1, a dichotomous key for the identification of nine salmonids of the Inland Northwest using six diagnostic skull bones; and associated equations to estimate total length and weight form bones ingested by piscivores or found in archeological sites; Chapter 2, Utilization of acoustic biotelemetry to define the movements of Lake Roosevelt Redband trout, oncorhynchus mykiss gairdneri" (2015). EWU Masters Thesis Collection. 323.