Resource use of great hammerhead sharks (Sphyrna mokarran) off eastern Australia

Raoult, Vincent; Broadhurst, Matt K.; Peddemors, Vic M.; Williamson, Jane E.; Gaston, Troy F.

Title: Resource use of great hammerhead sharks (Sphyrna mokarran) off eastern Australia
Creator: Raoult, Vincent; Broadhurst, Matt K.; Peddemors, Vic M.; Williamson, Jane E.; Gaston, Troy F.
Relation: Journal of Fish Biology Vol. 95, Issue 6, p. 1430-1440
Publisher Link: http://dx.doi.org/10.1111/jfb.14160
Publisher: Wiley-Blackwell
Resource Type: journal article
Date: 2019
Description: Great hammerhead sharks Sphyrna mokarran are the largest member of Sphyrnidae, yet the roles of these large sharks in the food webs of coastal ecosystems are still poorly understood. Here we obtained samples of muscle, liver and vertebrae from large S. mokarran (234–383 cm total length; L_T) caught as by‐catch off eastern Australia and used stable‐isotope analyses of δ¹⁵N, δ¹³C and δ³⁴S to infer their resource use and any associated ontogenetic patterns. The results indicated large S. mokarran are apex predators primarily relying on other sharks and rays for their diet, with a preference for benthic resources such as Australian cownose rays Rhinoperon neglecta during the austral summer. Teleosts, cephalopods and crustaceans were not significant components of S. mokarran diets, though some conspecifics appeared to rely on more diverse resources over the austral summer. Ontogenetic shifts in resource use were detected but trajectories of the increases in trophic level varied among individuals. Most S. mokarran had non‐linear trajectories in ontogenetic resource‐use shifts implying size was not the main explanatory factor. Stable isotope values of δ¹³C and δ³⁴S in muscle suggest S. mokarran span coastal, pelagic and benthic food webs in eastern Australia.
Subject: 34S; diet; ecological niche; MixSIAR; stable isotopes; sulphur; vertebrae
Identifier: http://hdl.handle.net/1959.13/1421801
Identifier: uon:37768
Identifier: ISSN:0022-1112
Language: eng
Full Text
Reviewed

Hits: 2415
Visitors: 2802
Downloads: 409

		Thumbnail	File	Description	Size	Format
View Details Download			ATTACHMENT02	Author final version	9 MB	Adobe Acrobat PDF	View Details Download