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Prey composition and ontogenetic shift in coastal populations of longnose gar Lepisosteus osseus
Author(s) -
Smylie M.,
Shervette V.,
McDonough C.
Publication year - 2015
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/jfb.12759
Subject(s) - trophic level , biology , predation , sciaenidae , clupeidae , pelagic zone , ecology , estuary , isotope analysis , benthic zone , bay , polychaete , ontogeny , apex predator , fishery , zoology , oceanography , fish <actinopterygii> , geology , genetics
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.