Tapachula ,Mexico

Please I need some advice . What would the best non-slr super zoom digital camera for taking wildlife photoes. I need to take photoes of wild otters as part of research and some photoes may be at dawn and dusk, with maybe some low light conditions. I'm looking for a minimum of 400-500mm telephoto and prepared to buy a telephoto converter if available. So far I am inclining towards the Panasonic FZ30, Canon SIS or maybe the Fuji Fine Pix S9000(great for low light but no image stabilizer and lower telephoto capability.) . After reading conflictive reviews i'm even more undecided! What is noise exactly and is it really that bad on the FZ 30? My price range is between 400 and 600 dollars

Muchas gracias!