Short-term shifts of stable isotope (13C, 15N) values in juvenile sharks within nursery areas suggest rapid shifts in energy pathways Academic Article uri icon

abstract

  • 2015 Elsevier B.V. We quantified temporal changes in blood plasma 13C and 15N values collected from recaptured juvenile blacktip reef sharks (Carcharhinus melanopterus, n=14) and sicklefin lemon sharks (Negaprion acutidens, n=4) at liberty in Moorea, French Polynesia for 10-50days, and juvenile bull sharks (Carcharhinus leucas, n=7) at liberty in the Florida Coastal Everglades for 34-127days to investigate shifts in assimilated biomass from energy reserves and consumed biomass. Blacktip reef and bull sharks exhibited significant changes in plasma 13C as they grew, with a mean 13C/cm total lengthSD of 0.41/cm0.72 and-0.82/cm0.67. While low sample sizes precluded statistical analyses, sicklefin lemon exhibited a change of 0.49/cm0.77. Blacktip reef sharks and bull sharks also exhibited significant shifts in 15N values-mean 15N/cm TLSD=-0.23/cm0.59, and -0.24/cm0.20; shifts in 15N values for sicklefin lemon sharks averaged 0.19/cm0.52. When data were normalized across species (accounting for species-specific difference in 13C and 15N ranges), no significant difference were found in the rate of 15N change between bull and blacktip reef sharks, but mean changes in 13C/day among blacktip reef and sicklefin lemon sharks (~1%/day) were twice as fast as bull sharks (~0.5%/day). Comparisons between plasma and muscle isotope values in bull sharks yielded similar results to comparisons of plasma isotope values - rapid changes in 13C and 15N. The magnitude and direction of changes in 13C and 15N values, however, were not uniform among individuals within each species, suggesting intraspecific variation in trophic interactions within the shark nurseries studied. Further studies quantifying shifts in energy pathways may contribute to elucidating the factors that shape foraging development in sharks and variation in trophic interactions within shark nurseries.

published proceedings

  • Journal of Experimental Marine Biology and Ecology

altmetric score

  • 8.25

author list (cited authors)

  • Matich, P., Kiszka, J. J., Heithaus, M. R., Mourier, J., & Planes, S.

citation count

  • 16

complete list of authors

  • Matich, Philip||Kiszka, Jeremy J||Heithaus, Michael R||Mourier, Johann||Planes, Serge

publication date

  • April 2015