Benthic ctenophores (Platyctenida: Coeloplanidae) in South Florida: predator–prey interactions |
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| Authors: | Peter W Glynn Brian Coffman Karim D Primov Shannon G Moorhead Jeongran Vanderwoude Rachel N Barrales Megan K Williams Robert P Roemer |
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| Institution: | 1. Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA;2. Department of Biological Sciences, Southeast Environmental Research Center, Florida International University, Miami, Florida, USA;3. Undergraduate Marine and Atmospheric Science Program, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Coral Gables, Florida, USA;4. Department of Marine Ecosystems and Society, Shark Research and Conservation Program, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA;5. Ecosystem Science and Policy Program, College of Arts and Sciences, University of Miami, Coral Gables, Florida, USA |
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| Abstract: | The primary goal of this study was to demonstrate, from field observations and laboratory experiments, some key trophic roles of benthic ctenophores as predators and prey in subtropical communities. We examined individuals of two benthic platyctenid species: Coeloplana waltoni, a minute epibiont on octocorals in exposed, open‐water settings; and Vallicula multiformis, an associate of calm‐water biofouling communities and floating Sargassum spp. Laboratory observations of individuals of both ctenophore species revealed frequent capture and ingestion of diverse zooplankton taxa, especially crustaceans. Laboratory predation trials demonstrated the capture of dolphinfish (Coryphaena hippurus) eggs and larvae by both ctenophore species. Dolphinfish eggs and larvae larger than individuals of C. waltoni were captured but not ingested during 2‐h trial periods. These prey items were sometimes purloined and ingested by polyps of the ctenophore's octocoral host. Ingestion of dolphinfish eggs and larvae by individuals of C. waltoni was observed, however, after longer periods of exposure to prey. In predation trials, dolphinfish eggs and larvae were both captured and ingested by larger individuals of the ctenophore species V. multiformis. Field and laboratory observations revealed diverse invertebrate and fish taxa that prey on both ctenophore species. In the laboratory, the mean daily per capita consumption of individuals of C. waltoni by a pomacanthid fish ranged 0.5–2.8 individuals, and ranged 2.6–3.6 individuals for predation by an ovulid mollusc. Field population densities of these predators ranged 0.1–0.7 individuals per m2 for the pomacanthid, and 0.2–1.1 individuals per m2 for the mollusc. Laboratory feeding observations demonstrated frequent consumption of individuals of V. multiformis by a sea anemone, and by three species of brachyuran crabs. Field observations revealed eight fishes that probably feed incidentally on individuals of V. multiformis. These findings add to the limited knowledge base of predator–prey dynamics in both C. waltoni and V. multiformis. |
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| Keywords: | ctenophore feeding predators zooplankton fish larvae biofouling community |
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