Growth rates and diet patterns for sympatric pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus throughout the Missouri River and lower Mississippi River were examined. Pallid sturgeon growth in the Great Plains Management Unit (GPMU) was slower than in other river reaches until age 9 and pallid sturgeon from the Interior Highlands Management Unit (IHMU) and Coastal Plain Management Unit (CPMU) did not differ. No differences in growth between management units were detected for shovelnose sturgeon. Observed differences in growth between pallid sturgeon and shovelnose sturgeon were generally dependent upon which growth model was used, but pallid sturgeon were typically larger after age 4. Diet is considered a primary driver of growth. Stable isotopes are capable of examining diet over longer time periods than gut content studies, but that time frame is dependent on which tissue is selected. Using fin clips, diet of both pallid sturgeon and shovelnose sturgeon was evaluated via stable isotopes. Pallid sturgeon and shovelnose sturgeon trophic position (TP) was influenced by management unit. There was a slight, but not significant, latitudinal trend with pallid sturgeon TP increasing by approximately one full TP between the GPMU and CPMU. Pallid sturgeon growth was negatively related to TP but was unrelated to δ13C in the Missouri River. Shovelnose sturgeon growth was not related to TP, but was negatively related to δ13C in the Missouri River. Dissimilarity in TP combined with differences in δ13C between species suggests low diet overlap between these sympatric species, and neither species should be used as a surrogate for the other for prey consumption studies. Further, pallid sturgeon differences between the GPMU and the rest of the management units suggest that individuals from the GPMU could be managed separately from those in other management units.
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-4712 |
| Date | 25 November 2020 |
| Creators | DeVries, Robert Jason |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
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