In the next few weeks, we will deploy a number of tags to bull sharks in Fiji. This includes pop-up satellite archival tags as well as acoustic tags. The satellite tags will be attached externally by approaching the shark underwater using SCUBA and a simple speargun. The tags are programmed to stay on the sharks for a few weeks up to three months. Experience from previous years tells me that this might be challenging! Bull sharks are good in getting rid of pop-up tags! Some of them only were attached to the sharks for a few days before they detached prematurely for unknown reasons. So keep your fingers crossed that they stay on the sharks for as long as they are programmed this time!
Acoustic tags will be either attached externally (same method as described above) or fed to the sharks. Stomach tagging allows to get information on stomach temperature at the same time and it is the least invasive method of tag attachment. However, the sharks eventually regurgitate the tags and therefore, tracking time is rather short with this method. The externally attached acoustic tags seem to work well and I have several bull sharks that have had the tags attached for several months now.
Despite tagging new sharks, I will also bring up all the acoustic receivers for downloading stored data and maintenance. Plus, we of course will continue our direct observation of fish in Shark Reef Marine Reserve which will include adding more species to the fish list I’m sure! And there are the remoras to keep an eye on! Lots of interesting stuff.
Watch this space for updates on how it goes!