title: Prey composition and ontogenetic shift in coastal populations of longnose gar Lepisosteus osseus.
abstract: Longnose gar Lepisosteus osseus were collected from May 2012 to July 2013 in the Charleston Harbor and Winyah Bay estuaries (SC, U.S.A.). This study examined trends in stomach fullness, described major prey components and their importance in the diet of L. osseus, compared stomach content-based trophic level estimates with the stable-isotope-based proxy: δ(15) N and tested for the occurrence of an ontogenetic diet shift using stomach content analysis and stable C and N isotopes (δ(13) C and δ(15) N). Dominant prey families were Clupeidae, Sciaenidae, Penaeidae, Fundulidae and Mugilidae, with the highest consumption rates in autumn. Trophic levels calculated using stomach contents did not correspond to δ(15) N (P > 0·05). Stomach contents and stable-isotope signatures indicate ontogenetic prey composition shifts from low trophic level benthic prey (fundulids) to higher trophic level pelagic prey (clupeids) as the fish grow between 400 and 600 mm in standard length. Due to their biomass, abundance and top predator status, L. osseus play a significant ecological role in the estuarine community composition, although this effect has often been overlooked by past researchers and should be considered in future estuarine community studies.
authors: Grice Marine Laboratory, College of Charleston, 205 Fort Johnson Road, Charleston, SC, 29412, U.S.A.
authors: M
authors: M
authors: Smylie
authors: Department of Biology and Geology, University of South Carolina Aiken, 471 University Parkway, Aiken, SC, 29801, U.S.A.
authors: V
authors: V
authors: Shervette
authors: Marine Resources Division, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, SC, 29422, U.S.A.
authors: C
authors: C
authors: McDonough
mesh_terms: D000818:Animals; D018533:Biomass; D002247:Carbon Isotopes / Q000032:analysis; D004032:Diet; D005399:Fishes / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D020387:Food Chain; D005766:Gastrointestinal Contents / Q000737:chemistry; D009587:Nitrogen Isotopes / Q000032:analysis; D011157:Population Dynamics; D011235:Predatory Behavior; D012621:Seasons
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes
keywords: estuarine communities; piscivore; stable isotopes; stomach contents; trophic level