Environmental Biology of Fishes

, Volume 97, Issue 9, pp 999–1012

A genetic technique to identify the diet of cownose rays, Rhinoptera bonasus: analysis of shellfish prey items from North Carolina and Virginia

  • Lyndell M. Bade
  • Christopher N. Balakrishnan
  • Erik M. Pilgrim
  • Susan B. McRae
  • Joseph J. Luczkovich
Article

DOI: 10.1007/s10641-014-0290-3

Cite this article as:
Bade, L.M., Balakrishnan, C.N., Pilgrim, E.M. et al. Environ Biol Fish (2014) 97: 999. doi:10.1007/s10641-014-0290-3

Abstract

Cownose rays are implicated in the consumption of commercially important shellfish on the U.S. East Coast. We tested this assumption by developing a molecular technique for species identification from cownose ray gut contents. Digestive tracts sampled from 33 rays in Pamlico Sound, NC and Chesapeake Bay, VA contained pieces of partially-digested tissue, well-digested tissue, fluid, and minute shell fragments which made visual identification to the species level nearly impossible. We sequenced the cytochrome oxidase subunit I (COI) for seven locally acquired bivalve species, chosen for their commercial and ecological importance in NC and VA. Sequences were used to design species-specific primers for each bivalve species to amplify polymerase chain reaction (PCR) products. We designed primers such that PCR products were sufficiently different in size to be distinguishable from one another when resolved on an agarose gel, and multiplexing of several species in one reaction was possible. Digestive tract sample testing revealed that cownose rays in Chesapeake Bay ate stout tagelus and soft shell clams. There was no evidence of the rays in the study consuming commercially important oysters, hard clams, and bay scallops. Further sampling over an extended period of time and additional locations is required to confirm these results. Our diagnostic tests could easily be expanded to elucidate the impact of cownose ray predation on prey populations.

Keywords

Elasmobranch Diet Feeding ecology Molecular techniques COI 

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Lyndell M. Bade
    • 1
    • 3
  • Christopher N. Balakrishnan
    • 1
  • Erik M. Pilgrim
    • 2
  • Susan B. McRae
    • 1
  • Joseph J. Luczkovich
    • 1
  1. 1.Department of BiologyEast Carolina UniversityGreenvilleUSA
  2. 2.Ecological Exposure Research Division U.S. EPACincinnatiUSA
  3. 3.Departments of Biology and ChemistryBates CollegeLewistonUSA