Lots of things have happened in Fiji since my last blog entry in September last year and I apologise for not keeping you updated. I was busy finishing a manuscript reporting the results from interviewing the locals living along the rivers. In the meanwhile, the paper has been accepted for publication by Environmental Conservation and will soon be available. Needless to say that we were happy learning that locals see and sometimes catch sharks in all the major rivers in Fiji. On the other hand, we were a bit surprised that nobody could tell us what species of shark they catch further upriver in low salinity/fresh water (there were some reports of hammerhead sharks, tiger sharks and other species from the river mouths). The names they used to describe the sharks were “baby shark” or “small shark”. So we set out to learn more about sharks in Fijian rivers and went fishing in the Navua River which is the one closest to the Shark Reef Marine Reserve. From acoustic monitoring we know that some of the large bull sharks we see (and tagged) at the Shark Reef Marine Reserve regularly show up at the mouth of the Navua River and we suppose that some of the large female bull sharks we see on Shark Reef give birth at the end of the year in this particular river. It would therefore be no surprise to find juvenile bull sharks in the Navua River. (more…)
9 February 2010
Fishing for sharks in Fijian rivers
3 September 2009
Sharks in Fijian rivers
One of the main goals of the Bull Shark Tagging Programme has been to locate the nursery grounds of the bull sharks encountered at the Shark Reef Marine Reserve in Fiji. From visual observations made over the years it became obvious that the sharks leave Shark Reef in September/October each year and start returning back to the site in December. Interestingly, female bull sharks that are clearly pregnant before they leave return non-pregnant and we also see quite a few females with fresh mating scars when they turn up in December/January at the site. So we are confident that reproduction takes place when they cannot be encountered in the Shark Reef Marine Reserve. Which also means that we should try to find their nursery grounds and movement corridors that link the protected area with habitats where they reproduce. In order to achieve this, I have been pop-up satellite tagging adult bull sharks at Shark Reef just before they leave the site in September. Unfortunately, there’s a lot of issues with externally attached pop-up satellite tags and this approach most likely will not tell us where the Fijian nursery grounds are.
14 August 2009
Rusi
His hallmark is his yellow hood he always wears when diving at the Shark Reef Marine Reserve. He knows more about sharks than anybody I know. Maybe not the hard scientific facts, but he spent his entire life diving in Beqa Lagoon off Fiji spending thousands of hours in the water with bull, tiger, lemon and all sorts of other sharks. He is the one that feeds the acoustic transmitters to the sharks and without his skills and knowledge I would know a lot less about bull sharks.
Comments (0)3 August 2009
The Shark Reef Marine Reserve: a marine tourism project in Fiji involving local communities
Shark Reef marine reserve in Fiji
It is with great pleasure that I announce the publication of a paper published in the Journal of Sustainable Tourism that reports on the concept, implementation and success of the Shark Reef Marine Reserve in Fiji. The Save Our Seas Foundation has been supporting this small-scale conservation project in the South Pacific almost from the beginning through the funding of the Bull Shark Tagging Programme that uses Shark Reef Marine Reserve as a superb site for field work.
Comments (0)18 June 2009
Tracking bull sharks with hand-fed intra-gastric acoustic tags
In principle, there are two ways to equip sharks with acoustic tags: you can either attach the tags externally or internally. For both methods there are good examples to be found in the scientific literature. If done internally, you would usually catch the fish for surgical tag implantation. An alternative method can be feeding acoustic transmitters to sharks. 
Stomach tagging can be an interesting option and it allows you to, for example, monitor the stomach temperature of the animal in addition to obtaining presence-absence data. However, the indigestible tag will eventually be regurgitated, most likely via stomach eversion, and therefore tracking time is limited. In order to feed a tag to a shark, all you need is the tag wrapped in bait and a site where you know you can attract the sharks close enough to a feeder. There’s no better place than the Shark Reef Marine Reserve in Fiji to test the feasibility of stomach tagging and to estimate tag retention time. And so we did. The superb photograph on the right (taken by Klaus Jost) gives you an idea of how it looks when you hand-feed a tag to a good-sized bull shark in Fiji.
