Well – it has been an interesting few days down here in Eleuthera. The rainy season is finally here after months of near drought conditions and as such we have spent a large portion of our time on the water dodging tropical deluges and lighting bolts. The rain is good news for our fresh water cisterns – our only source of fresh water at the Cape Eleuthera Institute – and also seems to be good news for sharks.
The last couple of days has seen the usual assortment of Caribbean reef sharks and nurse sharks but we have also been seeing some really big lemon sharks – the smallest at two meters but the four others at 2.6m – more like submarines than sharks. What I really need to see though is one more 2 meter plus tiger shark for another aspect of our research that I did not mention in my last post. It is our acoustic tracking program, a pilot study this year with the hope of expanding it in 2009/2010. We have an array of 56 under water acoustic hydrophones from the shallow waters of the mangrove creeks out to the pelagic waters of the Exuma Sound. We have surgically implanted thirteen, ten year acoustic transmitters which the hydrophone listen for and we have one more to put out – the last big tiger.
We did catch a the perfect candidate last Thursday – an beautiful female at about 2.5 meters – unfortunately she managed to get herself very tangled in the longline to the point that we had to cut her free. She was not doing very well when we released her and sunk to the bottom – we all feared the worse. I jumped in with some scuba gear to see how she was doing and as I approached her – cautiously as you can imagine – I could see she was still ventilating strongly. I turned her the right way up and tried to lift her off the bottom to pass more water over her gills which would help her recover. I was spectacularly unsuccessful in moving her due to her considerable bulk but just the act of righting her and shuffling her along the sea bed seemed to help and she started swimming off strongly. I returned to the surface and got back on the boat from where we followed her for 10 minutes until we were satisfied that she was going to be fine – much to the relief of the whole of the team.
It is a tough position to be in when we are doing all we can to protect these magnificent animals but though the assessment methods we use we might actually do them harm. I believe that the risk is worth the rewards – the greater good and all that – however it reinforced for me the need to develop and test alternative assessment techniques that can answer similar ecological questions less invasively – exactly what we are trying to do with this years project.