Evaluation of biopsy systems for sampling white shark Carcharodon carcharias (Lamniformes: Lamnidae) muscle for stable isotope analysis

Manual biopsy methods are typically used to obtain samples from free-swimming sharks but have had limited or varied success rates for different types of tissues. Muscle is the tissue desired when biopsies are used, however many methods fail to collect muscle and only collect dermis. The use of 3 different dart systems was described for manual biopsies and the success rate and tissue yield from white sharks at Isla Guadalupe, México was evaluated. Results suggest that the Reeb & Best biopsy system (RB dart) was best to biopsy muscle tissue because this dart was able to penetrate the dermal layer of white sharks is ~1.0 cm. Stable isotope analysis revealed no significant difference between outer and deeper muscle regions. A biopsy of 5.0 cm or less would be sufficient to obtain enough muscle for stable isotope and other kinds of analysis.