A couple weeks ago, we had the pleasure of welcoming Dr. Adam Barnett to the lab for more than a week. Adam has been doing some really interesting work on sevengill and tiger sharks, and hopefully we can get some projects going together soon! He also has been working on a great website with lots of information. Check it out at http://www.oceansiq.com!
I'll turn it over to him for a brief update of what he's been up to!
Among other projects, I have been working on
sevengill sharks Notorynchus cepedianus in
the temperate waters of south-east Australia and South Africa, and tiger sharks
Galeocerdo cuvier in north-east
Australia (see our research projects at oceansiq.com),
effectively studying two important apex predators in the two differing systems.
The sevengill shark work in Tasmania Australia has been quite comprehensive,
using a range of methods to show their habitat use patterns and the important
role they play in coastal ecosystems. The study in South Africa has only
recently begun and our focus site is False Bay, where we will also be
identifying habitat use, the importance of the aggregation site in False Bay
and the sevengill sharks’ role in the ecosystem. We will also examine if this
role varies when they share the coastal system with white sharks Carcharodon carcharias. White sharks and sevengill sharks are widely distributed in temperate waters
around the world, and these two co-occurring apex predators consume the same
prey (e.g. fur seals and other sharks). Adult sevengill sharks (up to 3 metres in
length) in coastal systems generally have little threat of predation, and any
predation would be expected to come from the larger white sharks (up to 6 m).
Despite this overlap in distribution and prey consumption, the relationship (if
any) between these two apex predators is unknown. The work in South Africa will
also provide the chance for cross regional comparisons in sevengill shark
ecology.
To date, our tiger shark work has focused on the
movement patterns of this species at Raine Island, the largest green turtle
nesting site in the world.
A diver coming face to face with a
sevengill shark at the aggregation site in False Bay, South Africa (photo
credit Morne Hardenberg)
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Taking blood from a sevengill alongside the boat (Photo Alison Kock) |
Underwater view of sevengill restrained alongside boat (Photo Adrian Hewitt) |