Hypoxia modifies planktivore–zooplankton interactions in Lake Erie

• Published in: Canadian journal of fisheries and aquatic sciences Vol. 69; no. 12; pp. 2018 - 2028
• Main Authors: POTHOVEN, Steven A, VANDERPLOEG, Henry A, HÖÖK, Tomas O, LUDSIN, Stuart A
• Format: Journal Article
• Language: English
• Published: Ottawa, ON NRC Research Press 01.12.2012; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Bythotrephes longimanus; Environmental aspects; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fish; Fishes, Fresh-water; Fresh water ecosystems; Freshwater; Freshwater zooplankton; Fundamental and applied biological sciences. Psychology; Hypoxia; Hypoxia (Aquatic ecology); Invertebrates; Lakes; Leptodora kindtii; Notropis atherinoides; Osmerus mordax; Plankton; Predation; Synecology; Lake Erie; Great Lakes of America; North America; America; Canada; Canada, Ontario, Erie L; Freshwater environment; Planktonophagous; Aquatic environment; Hypoxia; Zooplankton; Interaction
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/cjfas-2012-0144

We evaluated vertical distributions of fish and zooplankton, planktivore consumption, and prey production in Lake Erie during 2005 to determine how hypolimnetic hypoxia alters fish (i.e., rainbow smelt (Osmerus mordax) and emerald shiners (Notropis atherinoides)) and invertebrate planktivore (i.e., Bythotrephes longimanus and Leptodora kindtii) relationships with their mesozooplankton prey. Hypoxia concentrated 45%–76% of fish into a narrow (<2 m) metalimnetic layer, but only 3%–13% of zooplankton production was in this layer. The epilimnion may have served to some degree as a refuge for mesozooplankton because high temperatures may have excluded rainbow smelt. High concentrations of fish above the hypolimnion likely resulted in increased competition for large prey (i.e., predatory claodcerans). Although hypoxia did not result in overall high predation demands by planktivores relative to total zooplankton production, planktivore consumption rates within the metalimnion exceeded zooplankton production in that layer.