A team of 32 scientists have released a report that summarized 48 research project covering 318 reefs and 273 reef fish species during the period 1955-2007. The decline started about 1995. The scientists say the half of the fish species groups studied are decreasing at 2.6 to 6% loss per year. This loss rate is equal to 22 to 43 percent over 10 years. Because the species groups span game and commercial fish species as well as non commercial and non game fish species, over fishing is not the problem.
What is happening is a result of coral reef decline due to climate change, put more succinctly, "…drastic recent degradation of reef habitats… indicate that Caribbean fishes have begun to respond negatively to habitat degradation." Corals cover has been reduced "drastically" across the Caribbean region since the mid-1970s. The reduction is estimated to be 80% (Gardener 2003).
The reason that the team believe that the fish decline did not coincide with the reef decline is that coral skeletons persist for decades. It is the structure of the reef that provides much of the benefits of the reef habitat. After several decades, this structure starts to disintegrate an so goes the fish population.