Reef Diaries is the very young blog maintained by Red Mangrove Eco Adventures in Belize. My wife and I loved our honeymoon in Belize, and this sort of nature-oriented blog is always refreshing. What I think is so cool about Reef Diaries in particular is the thoughtful and circumspect treatment of the bull shark issue posted less than a month after the blog was launched. The writers treated the subject with seriousness and showed great respect for their readers; this is the only approach that allows those of us living in (for example) inland, cold, freshwater climes to appreciate the difficulties and challenges of the sensitive reef ecosystem.
I have added Reef Diaries to the sidebar, and you should check it out.