Trophic ecology of the blue shark (Prionace glauca) based on stable isotopes (δ13C and δ15N) and stomach content

Sandra Berenice Hernández-Aguilar, Ofelia Escobar-Sánchez, Felipe Galván-Magaña, Leonardo Andrés Abitia-Cárdenas

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Occupying the upper levels of trophic webs and thus regulating prey at lower levels, sharks play an important role in the trophic structure and energy dynamics of marine ecosystems. In recent years, the removal of these individuals from upper trophic levels as a result of overfishing has negatively affected ecosystems. We analysed the diet of blue sharks (Prionace glauca) caught off the west coast of Baja California Sur, Mexico, during the months of February-June in 2001, 2005 and 2006. We employed both stomach content and stable isotope analyses as each method provides distinct yet important information regarding the role of blue sharks in marine food webs, allowing us to estimate the relative contribution of different prey items to this predator's diet. Of the 368 stomachs analysed, 210 contained food (57%) and 158 (43%) were empty. Based on stomach contents and the index of relative importance (IRI), the pelagic red crab (Pleuroncodes planipes) was the most important prey, followed by the squids Gonatus californiensis (34.1%) and Ancistrocheirus lesueurii (10.4%). The mean (±SD) values for δ15N (16.48 ± 0.94‰) and δ13C (-18.48 ± 0.63‰) suggest that blue sharks prefer feeding in oceanic waters. The trophic level based on stomach content analysis was 4.05, while that based on the stable isotope analysis was 3.8, making blue sharks top consumers in the marine ecosystem of Baja California Sur, Mexico.

Original languageEnglish
Pages (from-to)1403-1410
Number of pages8
JournalJournal of the Marine Biological Association of the United Kingdom
Volume96
Issue number7
DOIs
StatePublished - 1 Nov 2016
Externally publishedYes

Keywords

  • Food habits
  • Mexican Pacific
  • sharks
  • stable isotopes
  • stomach contents

Fingerprint

Dive into the research topics of 'Trophic ecology of the blue shark (Prionace glauca) based on stable isotopes (δ13C and δ15N) and stomach content'. Together they form a unique fingerprint.

Cite this