Sadly a really really poor experience at GVI Seychelles, please don't be duped into spending your money here. Maybe I just got unlucky, but I am surprised to see so many good reviews considering the feeling of the volunteers whilst I was there.
From a research point of view- there was nothing to do, and far far too many volunteers to spread the little amount of work out between. There was very very little in terms of education or learning, not regular presentations and lectures as promised. None of the results of the limited data collected was shared with the volunteers. I left with the feeling that all I did for the environment was pollute the air with CO2 on my flight over. You basically just pay to hike around the (very lovely) surroundings and stand aimlessly around on beach for a bit.
The diet is extremely limited and poor (although it is hard for the staff to source good food in the Seychelles as it is limited). Any basic extras, or to even leave the island, you had to pay for yourself. The levels of hygiene in the kitchen was horrendous- there was a fridge that wouldn't even stay on so food would rot. There were rats running through the camp (and in people's beds) at night (although rats are a hard pest to control in an island environment). I did not go with expectations of any kind of luxury, but the standards were a joke (some volunteers had beds under a roof that leaked water onto your face every time it rained).
It was clear that there had been absolutely no investment in the base in a very long time; the fridge, cooker and kitchen area was abysmal, the solar panels were unable to provide any power past about 9pm, there was no fans to cool down the rooms. It is an absolute joke that GVI also tried to charge me £200 for 'cleaning expenses' on base (a plastic box with hand gel in- which we had to use as communal for the toilets).
I am left feeling ripped off, and with a sinking feeling in my stomach when I think about how much money I wasted on what was supposed to be a once in a lifetime trip. The volunteers pay thousands of pounds to be there, and I cannot see where the money goes because it is not going towards conservation, it is not going on investing in the base and it is not going towards staff salaries.
Overall, GVI is a for profit company, and the bottom line will always be profit. If you would like to do good in the world, get in touch with local organisations directly any bypass the middlemen such as GVI and don't fall for scams on the internet like I did.