First scientific paper published | Shark aggregation area in Fiji
Finally, after more than a years work excluding the actual fieldwork itself, my first scientific publication was published yesterday in Ecology & Evolution. Titled "Discovery of a multispecies shark aggregation and parturition area in the Ba Estuary, Fiji Islands", it is the outcome of my research there in 2015/2016. It has been a rough ride until here but I am more than happy that we managed to publish the work in a great journal and as open access, meaning everyone can have access to the information we provide.
While I didn't particularly care about which journal it would be in and the impact factor (veeeery important criteria in the science world), the one condition I had, was to publish it as open-access. Where is the use of providing information which might be vital for future decisions and conservation in the Fiji Islands, if the people have no access to it? Not much, in my eyes and thus I am grateful that it has worked out.[su_youtube url="https://www.youtube.com/watch?v=GNCRDHXoazE" width="400" height="300"]
The Ba Estuary - a shark aggregation area
Basically what I did was a fishery-independent survey (i.e. we fished ourselves and didn't rely on fishery statistics) to sample a bay in north-western Viti-Levu, the main island of the Pacific island nation of Fiji. I wanted to find out what sharks occur in the shallow waters, how old they might be, and where they occur within the bay. Together with Stefan, I came up with a sampling scheme that divided the relatively large area into seven sampling areas, that I then repeatedly visited to "fish" for sharks with a bottom-set gillnet and a longline.
Baby sharks of at least three species
If we (myself and my crew of fishermen) caught a shark, I quickly examined them for species, gender, the condition of the umbilical scar (which gives us insights into their age), measured them and took a DNA sample for later analysis back in Germany (to confirm the species) before releasing them back into the ocean.
After about five months and many, many hours on the 7m fiberglass boat in the Ba Estuary, my team and I had captured more than 100 sharks consisting of three different species:
- Blacktip sharks (Carcharhinus limbatus)
- Scalloped hammerhead sharks (Sphyrna lewini)
- Great hammerhead sharks (Sphyrna mokarran)
Interestingly, we only captured juveniles and new-born sharks, suggesting that this area might be used for parturition (giving birth) and might be subsequently utilized as a nursery area (an area where young sharks spend the first few months of their lives before moving on to different habitats). The study thus offers valuable first insights into the occurrence of sharks in Fiji. This study is particularly interesting as the two hammerhead shark species are considered "Endangered" by the International Union for Conservation of Nature (IUCN) making it even more important to identify these essential habitats for their reproduction and eventually ensure their protection. [pt_view id="6d325e77qk"]In theory, that sounds easy, but in practice, this is quite hard. There are a number of fishing villages that depend on these fishing grounds for their survival and a simple declaration as protected waters and a fishing ban would at the same time mean to rob them of the resources they need to survive. Thus, a middle-ground has to be found with one possibility being a temporary ban of the hotspots within the bay during parturition season when the abundance of baby sharks is the highest. We shall now just have to wait and see if our recommendations are somehow implemented...I hope you enjoy the read, and if there are any questions please do not hesitate to contact me!
Tom Vierus | Stefan Gehrig | Juerg M. Brunnschweiler | Kerstin Glaus | Martin Zimmer | Amandine D. Marie | Ciro Rico - Discovery of a multispecies shark aggregation and parturition area in the Ba Estuary, Fiji Islands
Big thanks again to Sharkproject e.V., Stop-Finning e.V., the KELLNER & STOLL Foundation, and all anonymous donors to the crowdfunding campaign that made this project possible.