Feeding ecology of three freshwater mussel species (Family: Unionidae) in a North American lentic system

• Published in: Hydrobiologia Vol. 850; no. 2; pp. 385 - 397
• Main Authors: Fogelman, Kaelyn J., Stoeckel, James A., Miller, Jonathan M., Helms, Brian S.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 2023; Springer; Springer Nature B.V
• Subjects: Aquatic ecological zones; Benthos; Biomedical and Life Sciences; Carbon; Carbon 13; Catabolism; Drawdown; Ecology; Endangered species; Feeding; Feeding behavior; Filter feeders; Food; Food resources; Fresh water; Freshwater; Freshwater & Marine Ecology; Freshwater ecology; Freshwater molluscs; Inland water environment; Internal energy; Interspecific; Lakes; Life Sciences; Littoral environments; Littoral zone; Mollusks; Mussels; Natural sciences; Nitrogen; Nitrogen isotopes; Organic matter; Particulate organic matter; Primary Research Paper; Survival; Suspended particulate matter; Threatened species; Wildlife conservation; Zoology; Benthic food web; Catabolism; Stable isotopes; Feeding ecology; Lake management; Unionidae
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-022-05080-8

Freshwater mussels are typically considered to be primarily filter-feeders with an ability to pedal feed, however there is limited information regarding interspecific differences in food resources and feeding modes. The objective of this study was to investigate interspecific variation in food resource usage among mussels in a lentic system associated with a reservoir drawdown. We quantified carbon-13 and nitrogen-15 isotopic signatures for three mussel species, including a Federally Threatened species, and their potential food resources in Gantt Lake, Alabama, USA. For all species, carbon-13 derived from limnetic, benthic fine particulate organic matter (FPOM) contributed on average 99% to the mussel diet. Paradoxically, mussels collected from the littoral zone relied primarily on food resources from the limnetic zone, although this spatial disconnect may have been an artifact of the sampling regime. Carbon-13 associated with littoral FPOM, limnetic and littoral suspended particulate organic matter (SPOM) and coarse particulate organic matter (CPOM) contributed < 1%.
Elliptio pullata
(Lea, Proceedings of the Academy of Natural Science 8: 262, 1856) collected live but emersed for 8 weeks were enriched in nitrogen-15, providing evidence of catabolism during emersion. Results suggest that benthic sources can be a dominant food resource for unionids and that stranded unionids rely on internal energy stores to survive emersion.