ESR 54:277-284 (2024)  -  DOI: https://doi.org/10.3354/esr01341

ABSTRACT: The great hammerhead shark Sphyrna mokarran and the scalloped hammerhead shark S. lewini are marine top predators with global distributions. However, limited information is available on the trophic ecology of hammerhead sharks in the Indian Ocean. In this study, we measured stable nitrogen and carbon isotopes in the muscle tissues of neonates and juveniles of S. mokarran and S. lewini from the waters of the western Arabian Gulf. In general, values of δ¹⁵N were lower in S. mokarran (10.8-18.7‰) than in S. lewini (12.2-18.7‰), indicating a reliance on food sources with low nitrogen values. Isotopic niche similarities were observed between female and male S. mokarran. We further observed considerable ontogenetic changes in the δ¹⁵N values of both S. mokarran and S. lewini neonates (a reduction from 19 to 12‰), reflecting the maternal effect. The effects of total length and sex on the nitrogen and stable isotope values were nonsignificant in S. mokarran juveniles. The western Arabian Gulf likely serves as a key feeding ground for both the neonates and the juveniles of S. mokarran. By contrast, S. lewini appears to have a low level of reliance on this region.

KEY WORDS: Hammerhead shark · Sphyrna · Arabian Gulf · Trophic ecology · δ¹⁵N · δ¹³C

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Cite this article as: Lin Y-J, Hsu HH, Nazeer Z, Panickan P and others (2024) Resource use by Sphyrna mokarran and S. lewini (Chondrichthyes) neonates and juveniles in the western Arabian Gulf: a stable isotope analysis. Endang Species Res 54:277-284. https://doi.org/10.3354/esr01341 Export citation Share:    Facebook - - linkedIn