Colorado State University
Cammack, Daniel L.
Thermal impacts on the early life history of Sauger (Sander canadensis).
Degree: MS(M.S.), Fish, Wildlife, and Conservation Biology, 2019, Colorado State University
Sauger (Sander canadensis), a large North American member of the family Percidae, often exhibit sporadic recruitment governed by a variety of biotic and abiotic factors. This episodic reproductive success is emblematic in Percids, as it has been documented across a wide geographic area for multiple Percid species. Temperature, the most influential abiotic variable, directly affects Percid recruitment, physiology, and distribution, while simultaneously modifying many other factors that govern population dynamics such as food abundance. The Wind and Bighorn River drainages of Wyoming, among the highest elevation tributaries of the Missouri River basin, remain a stronghold for two native Sauger populations. These populations are among the slowest growing and longest lived in the entire native range and provide an important recreational angling resource. While recent population trends have been positive (2011-2016), conditions in the past decade have resulted in poor recruitment, with only older age classes present in the annual Wyoming Game and Fish Department (WGFD) surveys of the Wind River population (2002-2011). Agency concern over poor recruitment resulted in the initiation of artificial spawning operations in both drainages, with the aim of bolstering these populations. Sauger hatch percentages from these spawning efforts were highly variable, and generally low across all years (0-75%). One hypothesis advanced to explain the observed variable egg survival was that river temperatures leading up to and during the spawn were outside of optimal ranges. Our research explored how temperature affects multiple stages in reproduction including adults, embryos, and prolarvae. Specifically, we tested the effect of temperatures in the range of 10-24°C on the survival and rates of development of Sauger embryos and prolarvae (phase I and II). In the incubation experiment, hatch rates were low for all treatments (<22%). Sauger embryos displayed appreciable thermal plasticity and no differences in hatch percentage were detected in the range of 12.2-18.9°C. Statistically lower hatch rates were detected for our 10°C and diel fluctuating (17-22°C) treatments compared to all others. Hatch timing and duration was inversely related with temperature. We developed a regression model to estimate temperature units (TU's) necessary to reach hatching and duration of hatch (days) based on average temperature. Our results indicate that optimal incubation temperature for Sauger is near 14.5°C. Sauger prolarvae survived at high rates (>90%) to the onset of exogenous feeding in all treatments ≥ 18°C, although pronounced mortality associated with the time that yolk was completely absorbed, suggested that starvation occurred, despite offering brine shrimp (Artemia nauplii) daily. Prolarvae in the 12 and 15°C treatments survived at a statistically lower rate to the onset of exogenous feeding and fed poorly after. We suggest that optimal temperature for prolarvae survival is in the range of 18-24°C with the caveat that rapid mortality can result…
Advisors/Committee Members: Myrick, Christopher A. (advisor), Johnson, Brett M. (committee member), Ghalambor, Cameron K. (committee member).
Subjects/Keywords: Sauger; Reproduction; Temperature
to Zotero / EndNote / Reference
APA (6th Edition):
Cammack, D. L. (2019). Thermal impacts on the early life history of Sauger (Sander canadensis). (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/195295
Chicago Manual of Style (16th Edition):
Cammack, Daniel L. “Thermal impacts on the early life history of Sauger (Sander canadensis).” 2019. Masters Thesis, Colorado State University. Accessed July 20, 2019.
MLA Handbook (7th Edition):
Cammack, Daniel L. “Thermal impacts on the early life history of Sauger (Sander canadensis).” 2019. Web. 20 Jul 2019.
Cammack DL. Thermal impacts on the early life history of Sauger (Sander canadensis). [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2019 Jul 20].
Available from: http://hdl.handle.net/10217/195295.
Council of Science Editors:
Cammack DL. Thermal impacts on the early life history of Sauger (Sander canadensis). [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/195295