Environmental Biology of Fishes

, Volume 91, Issue 2, pp 203–217

Trophic polymorphism in introduced pumpkinseed (Lepomis gibbosus) inhabiting Iberian reservoirs

  • Yakuta Bhagat
  • Michael G. Fox
  • Maria Teresa Ferreira
Article

DOI: 10.1007/s10641-011-9773-7

Cite this article as:
Bhagat, Y., Fox, M.G. & Ferreira, M.T. Environ Biol Fish (2011) 91: 203. doi:10.1007/s10641-011-9773-7

Abstract

Introduced pumpkinseed in Iberian reservoirs display marked external morphological differentiation along two simultaneous dimensions of flow and trophic structure. We assessed the degree of internal morphological differentiation using gill rakers, pharyngeal jaws and the levator posterior muscle among pumpkinseeds occupying four different habitats and determined whether prey consumption accounted for any discernible differences in feeding structures among ecomorphs. Results showed significant differentiation by habitat based on pharyngeal muscle and jaw dimensions in all study reservoirs, with pelagic pumpkinseeds having smaller jaws than littoral pumpkinseeds in four of the five reservoirs. Gill rakers, however, differentiated morphs in only three of the five reservoirs, corresponding to differences in zooplankton consumption among pelagic and littoral individuals in those reservoirs. Based on all internal morphological traits, greater divergence was seen along the littoral-pelagic trophic axis in the lacustrine zones of reservoirs compared to the fluvial zone. Overall differences noted in internal morphology are likely the result of phenotypic plasticity; the ability of this species to readily adapt to changing physical environments may explain the success of the pumpkinseed in its introduced range.

Keywords

EcomorphIntroducedInternal morphologyGill rakersPharyngeal jawsPharyngeal muscles

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Yakuta Bhagat
    • 1
    • 2
  • Michael G. Fox
    • 3
  • Maria Teresa Ferreira
    • 4
  1. 1.Environmental and Life Sciences Graduate ProgramTrent UniversityPeterboroughCanada
  2. 2.Annis Water Resources InstituteGrand Valley State UniversityMuskegonUSA
  3. 3.Environmental and Resource Studies Program and Department of BiologyTrent UniversityPeterboroughCanada
  4. 4.Forest Research CentreTechnical UniversityLisbonPortugal