Presentation #1: Satellite Tagging Tiger Sharks
Tiger shark (Galeocerdo cuvier) movement patterns and habitat use determined by satellite tagging in eastern Australian waters.
This study was designed to determine which areas of Eastern Australian Coast line that tiger sharks are inhabiting. They wanted to determine whether the sharks were sticking mainly to one location but with seasonal shifts or if they were migrating out into unprotected waters.
In order to track these animals, satellite tags are necessary because the sharks move around a lot and swim to depths that would be very difficult for humans to follow. The researchers used two different types of tags; PAT(pop-up archival tag) and SPOT5 tags(Smart Postioning and Temp. Transmitting Tag). The study used the satellite tags to track the path, depth and temperature that the sharks were swimming at. This information was then broken down into representative graphs of percentage of time spent at certain depths and temperatures.
Graphs shown above.
The two figures above are a combination of the data that the researchers collected ontop of a bathymetry map, which displays the depth of the water in the areas of interest. By mapping the paths of each tiger shark, the researchers were able to figure out where these animals were spending a majority of their time.
The graph shown above is another bathymetry graph but instead of the individual paths of the sharks, this graph shows what percentage of time that the sharks spent as a group in the areas around east Australia. With this information the researchers were able to determine whether the sharks were entering unprotected waters, like those off of the NSW(New South Wales) coast, where sport fishing and commercial fishing threaten tiger sharks every summer.
Citation of Journal Article: Holmes, B., Pepperell, J., Griffiths, S., Jaine, F., Tibbetts, I., & Bennett, M. (2014). Tiger shark (Galeocerdo cuvier) movement patterns and habitat use determined by satellite tagging in eastern Australian waters. Marine Biology, 161(11), 2645-2658.