Theses and Dissertations at Montana State University (MSU)
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Item Feasibility assessment for translocation of imperiled bull trout populations in Glacier National Park, Montana(Montana State University - Bozeman, College of Letters & Science, 2014) Galloway, Benjamin Thomas; Co-chairpersons, Graduate Committee: Christopher S. Guy and Clint MuhlfeldTranslocations are becoming an important tool for conservation and recovery of native fishes. However, many translocations have been unsuccessful likely due to inadequate feasibility assessments of abiotic and biotic factors influencing translocation success prior to implementation. This study provides a framework developed to assess the feasibility of translocating threatened bull trout Salvelinus confluentus into novel stream and lake systems in Glacier National Park, Montana (GNP). Populations of bull trout in GNP are at risk of extirpation in several lakes due to the establishment of nonnative invasive lake trout S. namaycush. Drainage-specific translocations of extant bull trout populations have been proposed as a possible management solution to these declines, but the suitability of translocation sites is unknown. This study evaluated the suitability of spawning, rearing, foraging, and overwintering habitats in three isolated headwater stream and lake systems (Logging, Camas, and Lincoln sites) to determine their suitability for bull trout translocation. A scoring framework was developed to compare the suitability of proposed translocation sites based on three major components: potential for the recipient habitat to support a translocation; potential for the translocation to negatively impact native aquatic biota; and ability of within-drainage donor populations to support a translocation. Scoring criteria were developed based on abiotic and biotic characteristics known to influence translocation success, including water temperature, habitat quantity and quality, habitat complexity, species composition, and the possibility of conducting within-drainage translocation. Based on the framework, the Camas site is the most suitable for translocation because it contains physical and biological conditions comparable to other systems supporting bull trout. The Logging site is the second most suitable site for translocation, whereas the Lincoln site is least suitable because it contains a minimal amount of stream habitat (< 300 m) and nonnative brook trout. These results will be used to prioritize and plan potential translocation strategies for imperiled bull trout populations in GNP and provide a framework for evaluating the feasibility of conducting translocations elsewhere.Item Identification of life history variation in salmonids using otolith microchemistry and scale patterns : Implictions for illegal introductions and for whirling disease in Missouri River Rainbow trout(Montana State University - Bozeman, College of Letters & Science, 2004) Munro, Andrew Roy; Chairperson, Graduate Committee: Thomas E. McMahon; Alexander V. Zale (co-chair)Proper conservation and management of wild salmonid populations requires correct identification of the array of life histories present and their contribution to adult recruitment. I used otolith microchemistry to identify natal origin and scale patterns to determine outmigration age in Missouri River rainbow trout where whirling disease could potentially cause a population collapse. First, I reviewed the otolith microchemistry literature and concluded that there have been a limited number of freshwater studies, and there has been limited rigorous testing of the many instruments used. Second, I tested the efficacy of time-of-flight secondary ion mass spectrometry (ToF-SIMS) and found that Sr:Ca could be precisely measured in an otolith 'standard', there is a strong relation between qualitative ToF-SIMS results and concentrations measured with an electron microprobe, and the ambient water strongly influences otolith composition. Third, I analyzed the chemical composition of lake trout otoliths to identify the likely source of illegally transplanted lake trout in Yellowstone Lake. Changes in otolith microchemistry of suspected transplants accurately (>90%) determined the likely source of the introduction, and transect analyses indicated that lake trout have possibly been in Yellowstone Lake since as early as the mid-1980s. Finally, I used otolith microchemistry to identify natal origin and scale patterns to identify outmigration age in Missouri River rainbow trout. Otolith microchemistry was not an effective technique for this particular system because of similarities between the two major rainbow trout producing tributaries. However, I demonstrated a technique that uses the relation between otolith and water Sr:Ca to estimate sample sizes required to detect differences between streams. This can be used in future studies as a preliminary test to determine if otolith microchemistry is feasible. Scale patterns revealed that the yearling outmigration life history contributed most (88%) to adult recruitment in the mainstem fishery and the proportion of young-of-the-year to yearling outmigrants did not change post-whirling disease. Rainbow trout in the Missouri River have two obstacles to overcome: 1) severe whirling disease infection if the natal stream has Myxobolus cerebralis; and 2) low probability of surival if they manage to avoid severe infection but leave the stream too early.