Ecology of reef fishes
This is part 5 of the essay about coral reefs.
The number of fish species that can be found on coral reefs exceeds all other environments on earth and most of them are also brilliantly coloured. Reef areas in the Philippines have the greatest number of species, over 2000. As for coral, the numbers of species in Atlantic reefs are significantly lower, perhaps 500.
There are several explanations to why there is such diversity among reef fishes. The reef provides numerous habitats such as areas of sand, caves and crevices but this alone cannot explain this explosion of species.
Reef fish at Richelieu Rock
Generally speaking, there are four models and although none of them can be said to be the ultimate explanation, they do provide a solution that may be part of the explanation. More research must be made in order to fully understand the enormous diversity
The competition model (Smith and Tyler, 1972) is the perhaps most classical. This model suggests that all species are highly specialized and all species have a set of adaptations that give it a competitive advantage in at least one situation on the reef.
The lottery model (Sale, 1977, 1980) is based on the large number of larvae produced by most coral reef fishes. These larvae are dispersed as plankton. Also, this theory states that fish are not specialized which means that there is active competition among the species. If one species is successful, it is the result of chance more than anything else.
The predation-disturbance model (Tabot, Russel, Anderson, 1978) suggests that the fish populations do not reach equilibrium. Unpredictable events and predation ensure that populations never become large enough to undergo competitive exclusion, which could explain the high diversity.
The recruitment limitation model (Victor, 1983 and Doherty 1982) claims that larval supply is never sufficient for the adult population to reach carrying capacity. The adult population reflects variation in the larval recruitment.
[...] The next section is about the ecology of reef fishes. [...]