Overcoming multi-year impacts of maternal isotope signatures using multi-tracers and fast turnover tissues in juvenile sharks

• Published in: Chemosphere (Oxford) Vol. 269; p. 129393
• Main Authors: Niella, Yuri, Raoult, Vincent, Gaston, Troy, Peddemors, Victor M., Harcourt, Robert, Smoothey, Amy F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2021
• Subjects: Animals; Carbon Isotopes; Humans; Infant, Newborn; Juvenile elasmobranch; Liver; Maternal signatures; Muscles; Nitrogen Isotopes; Sharks; Stable isotope analysis; Tissue turnover; Trophic ecology; Juvenile elasmobranch; Stable isotope analysis; Trophic ecology; Tissue turnover; Maternal signatures
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.129393

Stable isotopes are often used to determine the ecological role of different age classes of animals, but particularly for young animals this approach may be compromised. During gestation and or incubation body tissues of the young are derived directly from the mother. In neonates or post hatching, there is a period of transformation as the young grow and forage independently, but during this period different organs will continue to reflect the maternal isotopic signature as a function of their turnover rate. How long this maternal hangover persists remains poorly understood. We applied a multi-tracer approach (δ15N, δ13C and δ34S) to stable isotope signatures in juvenile bull sharks (Carcharhinus leucas) up to 6.5 years post parturition. We found that maternal provisioning was detectable for up to 3.5 years after birth in muscle but only detectable in young-of-the-year for liver. Inclusion of sulphur revealed when maternal signatures disappeared from low-turnover tissue, while also identifying the spatial and trophic ecology patterns from fast-turnover tissue. These results reveal the importance of sampling fast turnover tissues to study the trophic ecology of juvenile elasmobranchs, and how the use of only δ15N and δ13C isotopes is likely to make maternal patterns more difficult to detect. •Muscle of juveniles retained evidence of maternal influence for up to 3.5 years.•Liver of juveniles were no longer influenced by maternal input after one year.•Fast turnover tissues more accurately reflect the ecology of juvenile elasmobranchs.•Multiple tracers can improve the capability to identify maternal signatures.