Theses and Dissertations at Montana State University (MSU)
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Item Vital rates, annual abundance, and movement of white sharks in the northeastern Pacific(Montana State University - Bozeman, College of Letters & Science, 2020) Kanive, Paul Edward; Chairperson, Graduate Committee: Jay J. Rotella; Jay J. Rotella, Salvador J. Jorgensen, Taylor K. Chapple, James E. Hines, Scot D. Anderson, Barbara A. Block were co-authors of the article, 'Size-specific apparent survival rate estimates of white sharks using mark-recapture models' in the journal 'Canadian journal of fisheries and aquatic sciences' which is contained within this dissertation.; Jay J. Rotella, Taylor K. Chapple, Scot D. Anderson, Timothy White, Barbara A. Block and Salvador J. Jorgensen were co-authors of the article, 'Estimation of regional annual abundance and evidence for increasing numbers of white sharks off California' which is contained within this dissertation.; Jay J. Rotella, Taylor K. Chapple, Scot D. Anderson, Mauricio Hoyos-Padilla, Barbara A. Block, Salvador J. Jorgensen were co-authors of the article, 'Connectivity between the central California and Guadalupe Island white shark populations' which is contained within this dissertation.Reliable estimates of populations' vital rates and abundance are fundamental requirements for making assessments and informed management decisions regarding any species. For large marine fish species whose movements are extensive throughout ocean basins, data for individuals are difficult to acquire. Without empirical data, large assumptions must be made about a species' vital rates (i.e. survival and fecundity) to make population assessments, which can potentially lead to erroneous results. Using mark-recapture and acoustic-telemetry data, I conducted analyses estimating vital rates, annual abundance, and coastal movement for white sharks (Carcharodon carcharias) off California, US. First, I used a novel approach to estimate size-specific annual apparent survival rates and to test for differences in survival between sexes after accounting for imperfect sex assignment. Our results provide little evidence for differences in sex-specific survival rates. However, I estimated the first size-specific annual apparent survival rates for sub-adult and adult white sharks. Second, I estimated annual abundance for four white shark demographic groups off the coast of California over an eight-year study period. The estimated total annual population of sub-adult and adult white sharks increased from 180 to 266 individuals during the study. Additionally, group-specific population growth rate point estimates were all > 1.00, which indicates that all groups had positive annual positive growth during the study period, although, uncertainty around those estimates were greater for sub-adults than adults and does not rule out other possibilities for population trajectories. Finally, through collaboration between Mexico and the US, I was able to analyze a comprehensive acoustic telemetry dataset that explored connectivity between two main aggregation sites that form the northeastern Pacific population of white sharks. I found that movement between the two regions was rare and more probable to be sub-adult sharks. These analyses underscore the value of collecting and analyzing empirical data to develop reliable estimates of vital rates for a top marine predator. The work also illustrates the ongoing need to cultivate international research collaboration to include data from both the US and Mexico to make accurate population inferences for the northeastern Pacific population of white sharks.Item The effects of climate-warming on solitary bees and their interactions with plants(Montana State University - Bozeman, College of Letters & Science, 2019) Slominski, Anthony Hayden; Chairperson, Graduate Committee: Laura Burkle and Jia Hu (co-chair)The ecological consequences of anthropogenic climate-warming remain poorly understood for pollinators. In order to better understand these consequences, and thus the consequences of climate-warming for pollination services, we must determine how pollinator life histories mediate responses to climate-warming. To help address these research needs, we conducted three studies. First, we used field-collected solitary bee species (i.e., Osmia spp. and Megachile spp.) to investigate how overwintering life stage (i.e., adult versus prepupae), body size, and sex influenced solitary bee survival, weight loss prior to emerging, and timing of emergence in response to manipulated seasonal temperature and the durations of seasons. Second, we manipulated the amount of asynchrony (days) between female solitary bee emergence and flowering periods. We used a mesocosm-based experimental design to investigate the effects of phenological asynchrony on the female lifespan, female interaction rates with flowers, and reproductive success. In a third study, we manipulated the amount of phenological difference between conspecific male and female solitary bees (i.e., the degree of protandry; males emerging prior to females), and investigated the influence of sex-specific phenological responses to temperature on male-female interactions and reproductive success. Our main findings and subsequent conclusions were that i) compared to bees that overwinter as prepupae, patterns in weight loss prior to emergence, adult longevity, and timing of emergence suggested that post-emergence fitness in adult-wintering bees may decrease under climate-warming as a result of increased energy depletion at the time of emergence, increasing asynchrony with flowering periods, and sex-specific phenological responses, ii) asynchrony between a spring-active female solitary bee species (i.e., Osmia cornifrons) and flowering periods caused reductions in offspring body size and reduced interaction rates between females and flowers, which could have consequences for both bee and plant reproductive success, and iii) when the degree of protandry was either reduced or increased from an intermediate level, the probability of female offspring production tended to decrease. This suggests that changes in the degree of protandry may influence the fitness tradeoffs associated with protandry, resulting in consequences for current and future solitary bee reproductive success.Item Assessment of non-lethal tools to assign sex, stage of maturity, and reproductive condition in Burbot Lota lota(Montana State University - Bozeman, College of Letters & Science, 2019) McGarvey, Lauren Marie; Chairperson, Graduate Committee: Christopher S. Guy; Molly A. H. Webb (co-chair); Christopher S. Guy and Molly A. H. Webb were co-authors of the article, 'Description of gametogenesis and assessment of non-lethal tools to assign sex, stage of maturity, and reproductive condition in burbot Lota lota' which is contained within this thesis.; Christopher S. Guy and Molly A. H. Webb were co-authors of the article, 'Assessment of gonad size measured by ultrasound to assign stage of maturity and reproductive condition in burbot Lota lota' which is contained within this thesis.; Christopher S. Guy and Molly A. H. Webb were co-authors of the article, 'The assessment of non-lethal tools to identify mass ovarian follicular atresia in burbot Lota lota' which is contained within this thesis.Non-lethal tools (plasma sex steroid concentrations and ultrasound) were assessed to assign sex, stage of maturity, and reproductive condition (non-reproductive and reproductive) in Burbot Lota lota from Lake Roosevelt, Washington. Gonadal tissue, plasma samples, and gonadal sonograms were collected from Burbot. Gonadal tissue was processed for histological analysis to describe gametogenesis and confirm sex, stage of maturity, and reproductive condition. Plasma testosterone (T) and estradiol-17beta (E2) concentrations were measured by radioimmunoassay. Plasma 11-ketotestosterone (11- KT) concentrations were measured by liquid chromatography-mass spectrometry. Gametogenesis was described by gonadal histology during the entire reproductive cycle. Plasma sex steroid profiles, gonadosomatic index, and ovarian follicle diameter were also described during the entire reproductive cycle. Plasma 11-KT concentrations were used to assign sex with 81% accuracy during the entire reproductive cycle, and plasma 11-KT and E2 concentrations were used to assign sex with 98% accuracy during the reproductive phase (i.e., November to March in Lake Roosevelt). In females, plasma T concentration, plasma E2 concentration, and month were used to assign stage of maturity with 87% accuracy, and plasma T concentration and plasma E2 concentration were used to assign reproductive condition with 98% accuracy. In males, plasma 11-KT concentration, girth at the urogenital pore, and month were used to assign stage of maturity with 73% accuracy, and plasma T concentration was used to assign reproductive condition with 90% accuracy. Ultrasound was used to assign sex with 97% accuracy, and ultrasound measurements of gonad size were a promising tool to assign stage of maturity and reproductive condition. Non-lethal tools (plasma sex steroid concentrations, gonad size measured by ultrasound, and ovarian follicle diameter) were also assessed to identify mass ovarian follicular atresia in female Burbot. Plasma T concentrations and ovarian follicle diameter were promising tools to identify mass ovarian follicular atresia. Nonlethal tools to assign sex, stage of maturity, and reproductive condition will enable fisheries biologists to assess indices of reproductive potential for the Burbot population in Lake Roosevelt. Indices of reproductive potential can be used characterize and monitor population demographics, improve models of population growth, establish sustainable harvest regulations, monitor the effects of management actions, and monitor the effects of environmental stressors.