MEPS 599:147-156 (2018)  -  DOI: https://doi.org/10.3354/meps12626

Natural tags reveal populations of Conservation Dependent school shark use different pupping areas

M. N. McMillan1,*, C. Huveneers2, J. M. Semmens3, B. M. Gillanders1

1Southern Seas Ecology Laboratories, School of Biological Sciences and Environment Institute, University of Adelaide, Adelaide 5005, Australia
2School of Biological Sciences, Flinders University, Bedford Park 5042, Australia
3Institute for Marine and Antarctic Studies, University of Tasmania, Taroona 7053, Australia
*Corresponding author:

ABSTRACT: Knowledge of reproductive movements and sources of recruitment in highly mobile species is important to understand population-level resilience and to manage recovery in populations depleted by human interference. Management of the school shark Galeorhinus galeus (Linnaeus, 1758), a Conservation Dependent species in Australia subject to a national recovery strategy after stock collapse from overfishing, has long assumed obligate female migration to pupping areas in the southeast of their range. We used post-natal elemental signatures of individuals from 3 cohorts born in 1996 to 1998 as a proxy to test whether females use common pupping areas. Environmental or biological factors that differ among pupping areas can give rise to unique trace element signatures in shark vertebrae that act as natural tags and can be used to assess relative contributions from recruitment sources to adult populations. We compared post-natal signatures from sharks caught in 2 regions, South Australia in the northwest of the species’ range and Bass Strait in the southeast, using laser ablation inductively coupled mass spectrometry. Signatures were similar between regions for 1 cohort, suggesting high use of shared or similar pupping areas, but differed for the 2 remaining cohorts. Region of capture could also be accurately predicted (>75%) based on post-natal signatures, refuting the long-held view that all females use common pupping areas. We conclude that female movements and reproductive strategies are likely more plastic than previously assumed, highlighting the need to clarify them and their potential effects on resilience and conservation.


KEY WORDS: Behavioural plasticity · Laser ablation inductively coupled mass spectrometry · LAICP-MS · Partial migration · Reproductive strategies · Recovery · Resilience


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Cite this article as: McMillan MN, Huveneers C, Semmens JM, Gillanders BM (2018) Natural tags reveal populations of Conservation Dependent school shark use different pupping areas. Mar Ecol Prog Ser 599:147-156. https://doi.org/10.3354/meps12626

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