26 August 2014

Woolworths supports sevengill shark research

Alison Kock and Helen Lockhart

With thanks to Woolworths, the Two Oceans Aquarium recently handed over R150 000 to Dr Alison Kock, research manager for the Shark Spotters, who is leading an exciting five-year research project on broadnose sevengill sharks (Notorynchus cepedianus, also known as cowsharks).

The money was generated from the sales of the “shark/seventy-four” Ocean Promise reusable shopping bag, produced by Woolworths in collaboration with the Aquarium. In addition to this funding, the Aquarium has also provided logistical expertise and funding for a satellite tag.

Says Ralph Jewson, of Woolworths: “To be able to make a difference, something that is at the heart of what we do, is rewarding in itself, but to be at the forefront of what ultimately will inform conservation thinking of a species is really exciting and really urges us to do more, if and where we can. We appreciate that in order to conserve or protect a species, we first need to understand more about it.”

Ralph Jewson of Woolworths, Dr Alison Kock of Shark Spotters and Michael Farquhar, our curator. Photo courtesy of Reneé Leeuwner

The research project commenced in March 2013 with the intention of tracking sevengill sharks from False Bay, using acoustic tags and receivers, in order to learn more about the their behaviour.

Project achievements to date

To date the team has acoustically tagged 25 sevengills (so far all female, as the males are rarely encountered) and used pop-off archival satellite transmitters (PAT tags) to tag three more. PAT tags are programmed to collect and archive data such as depth and temperature before the tag releases from the animal at a pre-programmed time. The tag floats to the surface and the GPS position of the release location and archived data are sent to satellites passing overhead.

A diver and a sevengill shark. Photo courtesy of Morne Hardenberg

All three PAT tags have released from the sharks: two released prematurely and the third one released on schedule. The three sharks made totally different movements:

  • Shark 1 moved into deeper waters about 200km off the south coast of South Africa,on the Agulhas Bank. This shark spent most of its time at depths between 10 and 60m
  • Shark 2 remained within False Bay and recorded most of its time at depths of between 40 and 60m, which indicates that it spent most of its time outside of the aggregation area, which has a maximum depth of 12m
  • Shark 3 moved approximately 200km up the west coast, near Silverstroomstrand. This shark spent most of its time between 10 and 40m depth, with a maximum depth of 130m
PAT tag recovery. Photo courtesy of Dr Alison Kock

A member of the Aquarium’s collections team, Dean Hill, found the actual PAT tag on the beach near Silverstroomstrand, which was a stroke of luck as we are able to retrieve more information from the tag than is sent to us via satellite.

With an expected 10-year battery life for the acoustic tags, the research team is hoping to give the project a long-term focus, and extend this out of False Bay to other areas of South Africa.

“The funding from Woolworths and the Two Oceans Aquarium will allow us to purchase more acoustic transmitters and upgrade the acoustic receivers, which are necessary for the long-term monitoring objectives,” says Dr Kock. “We also now have enough funds to have two dedicated MSc students working on the project, which will allow us to achieve more consistent sampling.”

“I am delighted that we could help in such a way with such an important project, especially from a local perspective. I look forward to receiving the MSc proposals and staying more involved,” says Michael Farquhar, the Aquarium’s curator.

The Aquarium hopes to display cowsharks in its forthcoming dedicated shark exhibit, which is scheduled to open towards the end of 2015.

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