Environmental Biology of Fishes

, Volume 98, Issue 6, pp 1609–1622

Characterizing the bull shark Carcharhinus leucas habitat in Fiji by the chemical and isotopic compositions of their teeth

  • László Kocsis
  • Torsten W. Vennemann
  • Alex Ulianov
  • Juerg M. Brunnschweiler
Article

DOI: 10.1007/s10641-015-0386-4

Cite this article as:
Kocsis, L., Vennemann, T.W., Ulianov, A. et al. Environ Biol Fish (2015) 98: 1609. doi:10.1007/s10641-015-0386-4

Abstract

Bull sharks Carcharhinus leucas use estuarine and riverine systems as nursery habitat. The Shark Reef Marine Reserve (SRMR) on the southern coast of Viti Levu, Fiji, is well-known for its adult bull shark population. The species’ seasonal departure from the SRMR is related to reproductive activity, but nursery grounds have not yet been identified on the southern coast of Viti Levu. In order to further identify and characterise bull shark habitats in Fiji, 49 teeth were collected from bull sharks encountered at the SRMR and measured for their trace element concentrations, and 22 of them for oxygen isotopic composition in the phosphate group of bioapatite. The trace element analyses yielded relatively high Na, Mg, Sr, and F and low Ba concentrations for all the teeth supporting formation in marine environment. The phosphate oxygen isotope data concur with this result and the data evidently show that these teeth developed under marine condition relating to the temperature and oxygen isotopic composition of Fiji’s coastal waters. Therefore, the investigated teeth show no signs of freshwater habitat. Our results do not support the hypothesis that bull sharks enter freshwater habitats, at least not for longer time periods, during their absence from the SRMR. Additionally, the bull shark teeth had unexpectedly high zinc concentration at the very edge of the enameloid. This cannot be explained by environmental factors; therefore the high Zn content is interpreted here as a result of biological process, a reflection of enzyme (i.e., KLK4) related organic matter removal and enhanced crystallization during tooth maturation.

Keywords

Shark teeth Trace elements Oxygen isotopes in phosphate Zinc concentration Shark Reef Marine Reserve 

Supplementary material

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ESM 1(MOV 6266 kb)
10641_2015_386_MOESM2_ESM.pdf (227 kb)
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10641_2015_386_MOESM3_ESM.pdf (27 kb)
ESM 3(PDF 26 kb)
10641_2015_386_MOESM4_ESM.pdf (1.3 mb)
ESM 4(PDF 1329 kb)

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  • László Kocsis
    • 1
    • 4
  • Torsten W. Vennemann
    • 2
  • Alex Ulianov
    • 1
  • Juerg M. Brunnschweiler
    • 3
  1. 1.Institute of Earth Sciences, UNIL-GEOPOLISUniversity of LausanneLausanneSwitzerland
  2. 2.Institute of Earth Surface Dynamics, UNIL-GEOPOLISUniversity of LausanneLausanneSwitzerland
  3. 3.ZurichSwitzerland
  4. 4.Geology Group, Faculty of ScienceUniversiti Brunei DarussalamGadongBrunei Darussalam