Diets of Longnose Sucker in Yellowstone Lake, Yellowstone National Park, USA

• Published in: Journal of Freshwater Ecology
• Main Authors: Kaitlyn M. Furey, Hayley C. Glassic, Christopher S. Guy, Todd M. Koel, Jeffrey L. Arnold, Philip D. Doepke, Patricia E. Bigelow
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2020
• Subjects: diet composition; catostomus catostomus; longnose sucker; yellowstone lake; non-native fish; stomach content analysis; feeding ecology; envir; socio; Catostomus catostomus; Longnose sucker; Copepods
• Online Access: https://doi.org/10.1080/02705060.2020.1807421; https://doaj.org/article/ef81ede48afb47cea9607dc6ab1e14fb

Invasive species introduction and expansion is the second greatest threat to global biodiversity decline after habitat degradation. Introduced in the 1930s, the benthivorous Longnose Sucker (Catostomus catostomus) became established in Yellowstone Lake, Wyoming, USA, and used tributary streams for spawning. With this introduction, concerns were raised regarding their possible competition for food resources with native adfluvial Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri). Additionally, insufficient literature exists on Longnose Sucker feeding habits throughout their range, and there has been no comprehensive study of Longnose Sucker diet in Yellowstone Lake. The need exists for understanding the community ecology and food web dynamics in Yellowstone Lake, especially as non-native Lake Trout (Salvelinus namaycush) have caused declines in Yellowstone Cutthroat Trout through predation. The objectives of this study were to examine possible size-specific shifts in feeding habits, evaluate feeding strategy, and compare historical and contemporary diet data of Longnose Suckers in Yellowstone Lake. Diet data collected during summer of 2018 were analyzed by length-class to test for size-specific diet shifts. As Longnose Sucker length increased, copepods (Diacyclops bicuspidatus thomasi, Leptodiaptomus ashlandi or Hesperodiaptomus shoshone) decreased in proportion by weight. In contrast, dipterans (Chironomidae) and amphipods (Hyalella spp. or Gammarus spp.) varied in proportion by weight in the diet across length classes. We assessed the feeding strategy by evaluating the relationship between prey-specific abundance and percent frequency of occurrence. This assessment indicates that Longnose Suckers have a heterogeneous diet and generalized feeding strategy as all prey items had a prey-specific abundance value of <50%. Diet composition differed significantly between historical and contemporary samples, likely related to the differences in sampling locations and possibly due to a Lake Trout-induced ...