Theses and Dissertations at Montana State University (MSU)
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Item Relationships among swimming performance, behavior, water velocity, temperature, and body size for sauger Sander canadensis and longnose dace Rhinichthys cataractae(Montana State University - Bozeman, College of Letters & Science, 2015) Dockery, David Russell; Chairperson, Graduate Committee: Thomas E. McMahonMigration barriers and resulting habitat fragmentation are a major conservation concern for freshwater fishes. Characterizing the swimming abilities of fish is vital for fishway design and identifying potential movement barriers. The objective of this study was to assess the swimming performance of two of the most widely distributed prairie fishes, the large-bodied, large river sauger Sander Canadensis, and the small-bodied, small stream longnose dace Rhinichthys cataractae. Swimming performance for both species was assessed using a variety of metrics (passage success, maximum ascent distance, maximum sprint speed) in an open channel flume over a range of velocities (sauger, 51, 80, 93 cm/; dace, 39, 64, 78, and 90 cm/s), temperatures (sauger, 10.0, 14.3, 18.3°C; dace, 10.7, 15.3, and 19.3°C ) , and body sizes (sauger, 34.0-43.9 cm; dace, 4.6-12.4 cm). Passage success of sauger was surprisingly high (91%) over all test velocities, as was the mean maximum sprint velocity (mean, 219 cm/s). Contrary to expectations, water temperature and body size had little effect on swimming performance. Video observation showed that sauger transitioned from steady sustained swimming (aerobic metabolism) to unsteady, burst-glide or steady burst swimming (anaerobic metabolism) at 97 cm/s. Additional testing of sustained time of burst swimming by sauger in a swim tunnel (critical velocity, U sprint) showed they are capable of short term maximum bursts of 124 cm/s over a 15 second duration before fatigue. Longnose dace had high passage success in the test flume (95%) at test velocities of 39 and 64 cm/s, but success rate dropped markedly at higher velocities (66% at 78 cm/s and 19.7% at 90 cm/s). Dace swam along the bottom of the flume at all test velocities, but increased position-holding as velocity increased. Their maximum sprint velocity (139 cm/s) was about half that of sauger. Dace swimming performance generally increased with water temperature and body size.Item Observations on the life history and taxonomy of the sauger (Stizostedion canadense Smith) in Garrison reservoir, North Dakota(Montana State University - Bozeman, College of Letters & Science, 1960) Carufel, Louis H.Item Community structure and habitat associations of fishes of the lower Tongue and Powder rivers(Montana State University - Bozeman, College of Letters & Science, 2000) Trenka, Ryan JosephItem Competition potential between sauger and walleye in non-native sympatry : historical trends and resource overlap in the middle Missouri river, Montana(Montana State University - Bozeman, College of Letters & Science, 2006) Bellgraph, Brian Joseph; Chairperson, Graduate Committee: Christopher S. GuySauger Sander canadensis populations throughout Montana and North America have exhibited declines over the past few decades. Sauger population abundance declined in the middle Missouri and Yellowstone rivers of Montana in the mid-1980s following a period of drought. Higher flows resulted in a rebound of the lower Yellowstone River population; however, the middle Missouri River population has remained at low abundance. Various factors may contribute to the reduced population abundance of sauger in the middle Missouri River, including interspecific competition with walleye Sander vitreus. Historical trend data of sauger and walleye were assessed to determine long-term trends of sauger and walleye fitness. To assess competition potential, seasonal migrations, habitat use, and diets of both species were compared in the middle Missouri River. Trophic position of sauger was also compared between the middle Missouri and Yellowstone rivers to evaluate the trophic status of sauger in sympatry and allopatry with walleye. Sauger and walleye were tracked using radio telemetry to establish and compare seasonal migrations. Habitat use was compared at three hierarchical scales, diets were collected on fish sampled using electrofishing, and diet overlap was calculated.Item An empirical assessment of factors precluding recovery of Sauger in the lower Yellowstone River : movement, habitat use, exploitation, and entrainment(Montana State University - Bozeman, College of Letters & Science, 2004) Jaeger, Matthew Edward; Chairperson, Graduate Committee: Alexander V. ZaleSauger (Sander canadensis) were designated as a critically imperiled Species of Special Concern in Montana because of declines in distribution and abundance. Migratory barriers, habitat loss, entrainment in irrigation canals, and overexploitation, especially at times when sauger were aggregated, were suggested to explain the failure of Yellowstone River sauger to return to historical abundances. I characterized seasonal movement patterns, habitat use, and aggregation of sauger and estimated movement, exploitation, and Intake Canal entrainment rates to test these hypotheses. Seasonal movement, aggregation, and habitat use were investigated by telemetering and tracking 30 fish in 2001, 31 fish in 2002, and 30 fish in 2003. Exploitation and entrainment rates were assessed by tagging 957 sauger with reward tags. Tag-shedding rate (2.1%) was estimated by double-tagging and non-reporting rate (61.5%) was estimated using postcards as tag surrogates. Sauger aggregated near spawning areas in spring and subsequently dispersed 5 to 350 km to upstream home river locations where they remained for the rest of the year. During the spawning period, terrace and bluff pools, which are unique geomorphic units associated with bedrock and boulder substrate, were positively selected while all other habitat types were avoided. Tributary use during spawning was rare. Following movement to home river locations, sauger used most habitat types in proportion to their availability but selected reaches of specific geologic types. Exploitation occurred primarily in early spring and late autumn. Annual survival was high (61.3%). Entrainment in irrigation diversions may have accounted for more than half of non-fishing mortality. Migratory barriers, habitat loss, and overexploitation of adult sauger likely are not preventing sauger recovery, but the effects of these factors may be more pronounced for juvenile sauger. Habitat alteration and interactions with non-native walleye and smallmouth bass may also preclude recovery.