Trophic inferences of blue shark in MexicoPublished online on 04. June 2012
Trophic inferences of blue shark (Prionace glauca) in the Mexican Pacific from stable isotope analysis in teeth
Polo-Silva, C. J., Galván-Magaña, F. and Delgado-Huertas, A.
Isotopic analysis of biogenic tissues such as teeth of elasmobranchs has been well recognized as an important method to interpret present and past environmental conditions. However, few studies on shark teeth have focused their attention on making trophic inferences or reconstruction of diet.
We analyzed the carbon (δ13C) and nitrogen (δ15N) isotope composition of the tooth crown and root from blue sharks Prionace glauca caught in southern Baja California using a continuous-flow system by means of an elemental analyzer combined with a Delta Plus XL mass spectrometer, to describe their feeding ecology, considering sex and maturity stage.
Significant differences in δ13C values for tooth root were found between immature and mature males, with depleted values of 13C in immature individuals. No statistical differences were found between maturity stages in females for both the C and N isotopes in any part of the tooth, which suggests that females were consuming the same prey in the same area. In addition, we observed significant differences in δ15N values between the tooth crown and root.
Isotopic analysis in the tooth crown (dentin) and root may represent a new tool to describe the feeding ecology of different species of elasmobranchs, showing dietary change over a short timescale. Copyright © 2012 John Wiley & Sons, Ltd.
Rapid Commun. Mass Spectrom., 26: 1631–1638. doi: 10.1002/rcm.6275