Almost two months have passed since my first post about my project on a shark nursery here on Fiji. Time is literally flying and so much has happened since then. In the last weeks I have decided in accordance with my supervisor to concentrate on the Ba River only and to leave the Vitogo area sampling for now. Of course, it is tempting and the data would be just as good, but I rather collect more data around the Ba region and spend my remaining time “fishing” there. I have been to the village for several times by now, have a permanen room in the headman’s house and established excellent relationships with the fisherman, the fish market people and the inhabitants. Everyone in my team knows what to do, we’ve spent several days at sea if you combine all our sampling nights and work goes smootly.
The time in the village is interesting and full of wonderful moments and experiences, but at the same time it can be exhausting and very tiring. During my sampling days we areone the water for 7-9 hours, sometimes only coming home at 3am in the morning. Usually I do not get too much sleep, since life can be loud from a very early point in the morning and there is not much time for napping during the day. Village life usually starts around 5:30am and people do not make an effort to be particular quite. After my morning coffee and my daily vegan breakfast (which I happily introduced here), I usually digitalize my data from the previous night and then leave to town to visit the fish market, to do the necessary shopping and to get the fuel for the coming evening. Back in the village I do have some time to daze in the sun (it is very very hot in this area) or lie on my bed in the wind of the fan (which I have most of the time), play with the dogs, hang out with the villagers and snap some images around the village. There are no fences or whatsoever here and children happily run from one house to the other. Similar to my my time in South Africa, doors are always open and anyone seems to be welcome at any time (of course, if you are a stranger you should NOT just walk into a village and into houses – mind the local traditions and ceremonies!)
Depending on the tides and the fisherman we leave between 4pm and 7pm and then usually sample for six hours. Of course, we need time to get into the rivermouth area and to our sites which takes approximately 20-40 minutes and then to move in-between the sites, as I usually spend only two hours/night at one. Thus, six hours of fishing effort may mean eight or nine hours on the water. And that can be pretty long. Thanks god I have the little rechargable radio (which still works fine inspite of rusting slowly away) and thanks god for BULA FM. Nevertheless more understanding if Fijian would be very useful, since not all the guys are good at english (actually the majority isn’t).
After having explored the area for quite some time (meaning fishing at a lot of different sites for a short amount of time) and comducting a few questionnaires with the local fisherman fishing in the Ba river area, I have now come up with a plan for the coming weeks with areas where I’ll be concentrating the fishing effort and data collection. With the help of a good friend (thanks bro!!) and some very enriching talks about my project with several people, I have chosen eight areas differing in environmental conditions (e.g. shallow to deeper water edge, close proximity to rivermouth, shallow area…). At each site I collect environmental parameters like salinity, depth, turbidity (a measurement to determine how much particles are in the river: a rule of thumb says, the closer to the rivermouth the more turbid the water is – pH of the water and surface water temperature). Additionally conditions like weather, time and tide are noted down. And of course not to forget the main targets in this whole project: the sharks!
We have caught and tagged around sixty sharks so far plus additional ones I was able to process on the fishing market. Besides scalloped hammerheads (S. lewini), I am catching mostly potential spinner sharks (C. brevipenna) and have had a few great hammerheads (S. mokarran), too! Super exciting and incredibly beautiful animals which a huge dorsal fin! We are not sure whether the sharks I catch are blacktip sharks (C. limbatus) or as I mentioned Spinners – a DNA analysis will bring clear results. But I am pretty positive, what I find are the latter (which are not recorded here on Fiji yet) – looking forward to find out the truth!
Just around five days ago, one of the fishers in my village came to my house in the morning to tell me about some sharks he wanted to show me. In the very early day hours he had deployed his gillnet just a couple of hundred meters way from our village and deep within the river (around 15minutes boats drive to the rivermouth). One of the sharks had already been cut and processed to be cooked, but the other two were just gutted and could have a good look at them. Clearly, I had some bull sharks lying here. I was very excited to see them, the first ones I had ever seen in my life. I collected DNA samples from their pectoral fins, snapped a few images for identification and measured them before the fisherman continued to prepare them for their food. Great! This proves that we do have bulls within the river – another species added to the at least three species that we have been catching and tagging so far.
The one or other might condemn these people for eating the sharks, but honestly, there is little to prevent that. They have been fishing here for a very long time and shark bycatch is just a part of that. As they set out their gillnets for long periods of time, the sharks are usually dead when the net is hauled in. It is just logical to then utilize the shark meat instead of discarding it after the damage has already been done. Problems do occur though, when the number of operating fisherman and thus fishing pressure keeps increasing. There will be a tipping point where the natural birth rate and the number of females coming to shore to give birth to the pups is too low to compensate for the amount of baby sharks taken out the sea and river.
Just yesterday I returned to Ba, is a six hour bus ride from Suva, to sample another four nights and then spend the weekend on Ovalau, an island east of Viti Levu with my girlfriend and some friends. Looking forward to our “catches” this week and even more to releasing them back into their habitat hoping they have a long life, grow to big important predators and fulfill their role in our marine environment!
Stay tuned for the next part, where I will explain how I process the juvenile sharks and how we use a gillnet and a longline to catch them!
Tom is a marine biologist, photographer, and filmmaker specializing in conservation imagery and film. His scientific background is a strong asset in creating appealing imagery, articles, and short films. Tom has won several awards and nominations with his images and films, such as the German Prize for Science Photography in 2016/2017. Tom’s images and articles have been published in international magazines and newspapers such as The Guardian, Welt am Sonntag, Diver, Tauchen, In-flight magazines, Bild der Wissenschaften and more. In 2017 he launched www.tomvierus.com for a wider portfolio and business requests.
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