MEPS 554:115-128 (2016)  -  DOI: https://doi.org/10.3354/meps11807

Intraspecific variability in diet and implied foraging ranges of whale sharks at Ningaloo Reef, Western Australia, from signature fatty acid analysis

Lara Marcus1,*, Patti Virtue1,2,3, Heidi R. Pethybridge1,2, Mark G. Meekan4, Michele Thums4, Peter D. Nichols2

1Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tasmania 7001, Australia
2CSIRO Oceans & Atmosphere, GPO Box 1538, Hobart, Tasmania 7000, Australia
3Antarctic Climate & Ecosystems Cooperative Research Centre, Private Bag 80, Hobart, Tasmania 7001, Australia
4Australian Institute of Marine Science, c/o UWA OI (MO96), 35 Stirling Highway, Crawley, Western Australia 6009, Australia
*Corresponding author:

ABSTRACT: We examined the feeding ecology of whale sharks by analyzing the signature fatty acids of their sub-dermal tissue and those of an extensive set of potential prey collected at Ningaloo Reef, Western Australia, in 2013, 2014 and 2015. Sub-dermal tissue of whale sharks was low in lipid content (4.0 mg g-1 dry mass) and dominated by phospholipids (72% of total lipids), with a calculated energy density of 18.7 kJ g-1 dry mass. There was significant intraspecific variability in fatty acid profiles of whale sharks, with cluster analysis identifying 4 distinct groups in 2013 and 5 groups in 2014. As this variability was not related to sex or size-class, we suggest that it may be attributed to differences in the feeding habitats used by these groups of whale sharks. Variation in dietary patterns was also observed between years, likely due to changes in the primary and secondary producers. Examination of food web interactions showed that fatty acid profiles of whale sharks and their presumed prey were significantly different, suggesting that sharks fed over a wide range of habitats, including deep waters. Our findings show that signature fatty acids of sub-dermal tissue can be used to examine broad trophic pathways and to identify spatial and temporal changes in the diet of these large and wide-ranging animals.


KEY WORDS: Biochemical analysis · Chondricthyans · Elasmobranchs · Feeding ecology · Fatty acids · Lipids


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Cite this article as: Marcus L, Virtue P, Pethybridge HR, Meekan MG, Thums M, Nichols PD (2016) Intraspecific variability in diet and implied foraging ranges of whale sharks at Ningaloo Reef, Western Australia, from signature fatty acid analysis. Mar Ecol Prog Ser 554:115-128. https://doi.org/10.3354/meps11807

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