The trophic role of a large marine predator, the tiger shark Galeocerdo cuvier

作者：Ferreira, Luciana C.^*; Thums, Michele; Heithaus, Michael R.; Barnett, Adam; Abrantes, Katya G.; Holmes, Bonnie J.; Zamora, Lara M.; Frisch, Ashley J.; Pepperell, Julian G.; Burkholder, Derek; Vaudo, Jeremy; Nowicki, Robert; Meeuwig, Jessica; Meekan, Mark G.

来源：Scientific Reports, 2017, 7(1): 7641.

DOI：10.1038/s41598-017-07751-2

• STABLE-ISOTOPE ANALYSIS
• HABITAT USE
• INDIVIDUAL SPECIALIZATION
• DISCRIMINATION FACTORS
• LOGGERHEAD TURTLES
• WESTERN-AUSTRALIA
• SEASONAL-CHANGES
• MUSCLE-TISSUE
• NICHE WIDTH
• DIET

Tiger sharks were sampled off the western (Ningaloo Reef, Shark Bay) and eastern (the Great Barrier Reef; GBR, Queensland and New South Wales; NSW) coastlines of Australia. Multiple tissues were collected from each shark to investigate the effects of location, size and sex of sharks on delta C-13 and delta N-15 stable isotopes among these locations. Isotopic composition of sharks sampled in reef and seagrass habitats (Shark Bay, GBR) reflected seagrass-based food-webs, whereas at Ningaloo Reef analysis revealed a dietary transition between pelagic and seagrass food-webs. In temperate habitats off southern Queensland and NSW coasts, shark diets relied on pelagic food-webs. Tiger sharks occupied roles at the top of food-webs at Shark Bay and on the GBR, but not at Ningaloo Reef or off the coast of NSW. Composition of delta C-13 in tissues was influenced by body size and sex of sharks, in addition to residency and diet stability. This variability in stable isotopic composition of tissues is likely to be a result of adaptive foraging strategies that allow these sharks to exploit multiple shelf and offshore habitats. The trophic role of tiger sharks is therefore both context- and habitat-dependent, consistent with a generalist, opportunistic diet at the population level.

• 出版日期2017-8-9
• 单位东南大学