title: Trophic behaviour of juvenile reef fishes inhabiting interlinked mangrove-seagrass habitats in offshore mangrove islets.
abstract: Stable isotope (δ(13)C and δ(15)N) 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 δ(13)C 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.
authors.affiliation: Smithsonian Marine Station at Fort Pierce, 701 Seaway Dr., Fort Pierce, FL, 34949, U.S.A.
authors.forename: A
authors.initials: A
authors.lastname: Vaslet
authors.affiliation: U.S. Environmental Protection Agency, National Health & Environmental Effects Research Laboratory, Western Ecology Division, 200 SW 35th St, Corvallis, OR, 97333, U.S.A.
authors.forename: D L
authors.initials: DL
authors.lastname: Phillips
authors.affiliation: Smithsonian Museum Conservation Institute, 4210 Silver Hill Rd, Suitland, MD, 20746, U.S.A.
authors.forename: C A M
authors.initials: CA
authors.lastname: France
authors.affiliation: Smithsonian Environmental Research Center, Edgewater, MD, 21037, U.S.A.
authors.forename: I C
authors.initials: IC
authors.lastname: Feller
authors.affiliation: National Museum of Natural History, Smithsonian Institution, P. O. Box 37012, Washington, DC, 20013-7012, U.S.A.
authors.forename: C C
authors.initials: CC
authors.lastname: Baldwin
mesh_terms: D000818:Animals; D032407:Avicennia; D001499:Bayes Theorem; D001531:Belize; D002247:Carbon Isotopes / Q000032:analysis; D004032:Diet / Q000662:veterinary*; D017753:Ecosystem; D020387:Food Chain; D005766:Gastrointestinal Contents; D062312:Islands; D008962:Models, Theoretical; D009587:Nitrogen Isotopes / Q000032:analysis; D010473:Perciformes / Q000502:physiology*; D043982:Rhizophoraceae
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes
keywords: SIAR; SIBER; fish foraging habitats; gut contents; marine ecosystems; stable isotopes