Initial Data Analysis is In: Biopsies don’t Bother White Sharks

5th November 2015 | by

Remember in previous blog post Taking Tiny Pieces of the Great White Shark, when I said that the sharks aren't bothered when we take biopsies from them? Well now it's scientific fact!

Initial Data Analysis is In: Biopsies don’t Bother White Sharks

My good friend and colleague Simone Rizzuto (www.carcharesearch.wordpress.com) analysed the behaviour of the sharks that we took samples from and presented the results at the European Elasmobranch Association Conference, held in October in Peniche, Portugal.

Authors: Simone Rizzuto1 · Georgia French2,3 · Marlene Sturup2 · Alison Towner4· Letizia Marsili5 · William Hughes 2· Johannes H. van Wyk1

Affiliations:

1 University of Stellenbosch

2 University of Sussex

3 SharkStuff www.sharkstuff.co.uk www.facebook/GeorgiaSharkStuff @GeorgiaSharky

4 Dyer Island Conservation Trust www.dict.org.za

5 University of Siena

Here you can read a summary of the work done and the results:

ABSTRACT: White sharks are protected in several countries under national legislation through the Convention of Migratory Species (CMS) and the Convention of the International Trade in Endangered Wild Flora and Fauna (CITES), considered as vulnerable by the International Union for Conservation of Nature (IUCN). The conservation status of this top predator calls for increased research effort to support effective management of white shark populations. For this purpose, it is necessary to develop minimally invasive methods, such as obtaining biopsies, as an alternative to sacrificing animals or relying on naturally deceased ones, to study physiological, genetic and toxicological endpoints. In 2015, dermis and muscle tissue biopsies were collected from 32 white sharks (from 2.5 to 4.6 m total length) in the licensed Gansbaai shark cage diving area (South Africa). We evaluated the success rate of “Finn Larsen Ceta Darts” sampling probes. Dermis success rate (DSR) and Muscle Success Rate (MSR) is defined as the percentage of biopsy samples containing the respective tissues. The results showed high DSR (84.61%) and MSR (79.49%), suggesting that probes (4 cm length and 0.9 cm diameter) are able to penetrate white shark dermal layer (0.99 ± 0.05 cm) collecting sufficient muscle tissue (1.64 ± 0.11 cm) for a variety of analyses. We also evaluated the behavioral responses of the sharks to biopsy in addition to the time period between the biopsy and the moment the shark was sighted again. The most observed behavior (N=18), was “no reaction”, followed by an increase in speed and/or change of direction (N=14). Of the 32 sampled sharks, 29 were sighted again following the biopsy event in an average of 19 minutes, and the other 3 were seen again not more than a day later. This study supports the hypothesis that tissue biopsy is not only a useful method to collect high quality tissue samples (including dermis an muscle tissue), but also minimally affects the behaviour of white sharks.

Back to all News

Keen to learn more? SharkStuff would love to hear from you!

Contact us
Website by EDNA - Design For Wildlife
© Copyright 2021 SharkStuff - All Rights Reserved.
SharkStuff is a legally constituted, UK-based Small Charity. All rights reserved.