Brook trout invasion into bull trout streams is variable, and likely influenced by a suite of biotic and abiotic factors. Field observations revealed that brook trout dominated the fish community over bull trout in warmer sites that had undercut banks; in contrast, bull trout dominated in colder sites that had a high amount of large substrate cover, and where alternate non-native species were present. Laboratory studies of competition between the two species revealed that bull trout use a scramble foraging tactic, whereas brook trout use a territorial tactic. Bull trout outcompeted brook trout when fish density was low and habitat complexity was high, as this scenario reduced the effectiveness of the aggressive territorial foraging strategy of brook trout. Bull trout from a migratory population competed more successfully against brook trout and had higher rates of oxygen consumption than those from a resident population. This combined field-lab study points to some of the abiotic and biotic factors that affect competition between the two species, and may influence the outcome of brook trout invasion into bull trout streams. / xiv, 184 leaves : ill. ; 29 cm

Reclamation on the Cardinal River and Gregg River coal mines includes the construction of mine pit lakes connected to stream environments. Key physical, chemical and biological parameters of these “truck and shovel” lakes and their streams were investigated, and hypotheses regarding ecosystems and populations were tested. Findings include: Sphinx Lake and Pit Lake CD exhibit meromictic (partial-mixing) tendencies, but still function in a similar fashion to shallower, natural sub-alpine lakes. Elevated selenium concentrations as high as 16 ug/g (dry weight) were recorded in Rainbow trout (Oncorhynchus mykiss) eggs taken from gravid Sphinx Lake and Pit Lake CD fish. Potential detrimental effects associated with the bioaccumulation of selenium on fish reproduction were not observed. Stream water temperatures downstream of Sphinx Lake and Pit Lake CD were significantly warmer than in inlet streams and streams without pit lakes. Streambed concretions caused by calcite precipitation were documented and found to affect portions of the upper Gregg River basin. Remediation of this concretion is important for sustainability of trout populations. Aquatic communities including fish, invertebrates, zooplankton and aquatic plants are present in these pit lake systems. Athabasca Rainbow trout populations are self-propagating (spawning at the outlets) with higher densities downstream than there were prior to lake reclamation. The development of sub-alpine mine-pit lakes connected to the stream environment appears to be an appropriate and beneficial reclamation technique in this area. / xvi, 224 leaves : col. ill., map ; 28 cm

Many communities are currently seeking to balance urban water needs with preservation of sensitive fish habitat. As part of that effort, CE-QUAL-W2, a hydrodynamic and temperature model, was developed for Chester Morse Lake and the lower Cedar River, WA. Chester Morse Lake is approximately 10 km long with a maximum depth at full pool of 40 m. The Cedar River model started immediately downstream of the Chester Morse dam and ended 21 km downstream at Landsburg, where drinking water is diverted for the City of Seattle. This water quality model was coupled with a fish habitat and bioenergetics model for bull trout and was calibrated to temperature data between 2005 and 2008. Bull trout fish bioenergetics parameters were provided by the USGS. The CE-QUAL-W2 model was found to be highly accurate in modeling temperature variation in the lake - at most locations having an average absolute mean error of between 0.5 and 0.8 oC. The Cedar River model had an average absolute mean error of 0.7oC. This tool is designed to allow managers and operators to estimate the impact to fish habitat and growth potential from various management decisions including extent of drawdown, timing/volume of flows, and various pumping operations. Future studies could include incorporating further water quality parameters such as nutrients, algae, and zooplankton as they relate to fish productivity.