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.
