Background:The estimated number of fishes on Moorea is around 550 species. We have sequenced >85% (483 taxa) of the estimated fish diversity in Moorea, and virtually all of the ecologically important and relevant species. This achievement was possible because of a partnership forged between MBP and the Laboratory of Analytical Biology (LAB) at the Smithsonian Institution. One significant fraction of marine vertebrate diversity was not captured in the pilot phase (the extent of which will be partially revealed in larval fish surveys – see 3.2.1) is the deep reef fauna (>40m), generally inaccessible by traditional diving methods.
Across the Indo-West Pacific (IWP), this region has rarely been explored but is the source of umerous newly described fish species. It is estimated that there might be 150-200 species still to be found at these depths in Moorea. We have recruited Richard Pyle and his team of deep diving researchers to assist in sampling the deep reef communities around Moorea. Pyle has found as many as 12 new species per hour of collecting time, at a newspecies rate as high as 50% of overall assemblage. In Vanuatu he collected 134 specimens of about 70-75 species in 3 weeks of diving, but that was all at one general area, and with a lot of time spent collecting invertebrates. With two 3-week trips, with more diverse sites, these numbers could be doubled for Moorea.
Significance:Specimens from these deeper habitats will be of great scientific value for several reasons. Based on past results, we can expect as many as 50% of the fish species collected to be new to science, and perhaps a higher proportion of collected invertebrates will likely be new. The survey will also allow comparison with shallow-reef material, both in terms of species richness, and in terms of phylogentic affinities (e.g., are deep-reef species generally more closely-related to other deep-reef species; or are the deep-reef species generally recently divergent off-shoots from the shallow-reef species). This will also represent the first deepreef survey of this sort in French Polynesia, allowing for interesting biogeographic comparisons with other surveyed deep reefs elsewhere in the Pacific. One of the emerging patterns from previous work of Pyle and colleagues is an apparent lack of any diversity attenuation moving eastward across the Pacific in the deep sea fauna. This contrasts to the well-documented biodiversity gradient observed at shallower depths and on land. Thus, whereas the shallow fauna in Moorea is no doubt much less than that of Vanuatu; the deep fauna might be comparable in both places. This is one of the hypotheses the MBP will test.