Trophic behaviour of juvenile reef fishes inhabiting interlinked mangrove–seagrass habitats in offshore mangrove islets |
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Authors: | A Vaslet D L Phillips C A M France I C Feller C C Baldwin |
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Institution: | 1. Smithsonian Marine Station at Fort Pierce, Fort Pierce, FL, U.S.A.;2. U.S. Environmental Protection Agency, National Health & Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR, U.S.A.;3. Smithsonian Museum Conservation Institute, Suitland, MD, U.S.A.;4. Smithsonian Environmental Research Center, Edgewater, MD, U.S.A.;5. National Museum of Natural History, Smithsonian Institution, Washington, DC, U.S.A. |
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Abstract: | Stable isotope (δ13C and δ15N) and gut content analyses were used to investigate size‐related feeding habits of four reef fishes (the beaugregory Stegastes leucostictus, the french grunt Haemulon flavolineatum, the schoolmaster snapper Lutjanus apodus and the yellowtail snapper Ocyurus chrysurus) inhabiting an offshore (non‐estuarine) mangrove islet off Belize, Central America. Comparisons of isotopic niche space and Schoener diet similarity index suggested a low to moderate degree of niche overlap between fish size groups. The δ13C gradient between mangrove and seagrass prey as well as results of Bayesian mixing models revealed that sampled fishes relied mostly on seagrass prey items. Only small and large juveniles of the carnivorous species L. apodus derived a part of their diet from mangroves by targeting mangrove‐associated Grapsidae crabs and fish prey, respectively. Isotopic niche shifts were particularly obvious for carnivorous fishes that ingested larger prey items (Xanthidae crabs and fishes) during their ontogeny. The utilization of mangrove food resources is less than expected and depends on the ecology and life history of the fish species considered. This research highlights that mangrove‐derived carbon contributed relatively little to the diets of four fish taxa from an offshore mangrove islet. |
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Keywords: | fish foraging habitats gut contents marine ecosystems SIAR SIBER stable isotopes |
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