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The ecology of reef fish varies with depth, although patterns in diversity remain largely undescribed, in particular the complementarity of their taxonomic, functional and phylogenetic facets. In the present study we investigated patterns of taxonomic, functional and phylogenetic diversity of fish on 21 reefs, at depths ranging from 3 to 31 m, at Prı'ncipe Island (Gulf of Guinea). Taxonomic and functional diversity decreased monotonically with depth; the pattern was less accentuated for phylogenetic diversity. Functional diversity was saturated at high levels of taxonomic diversity, reflecting redundancy in species traits, particularly at the shallower reefs. Functional diversity increased linearly with phylogenetic diversity; thus, increasing niche availability seems to translate into a larger diversity of phylogenies. Dissimilarities in the structure and composition of fish assemblages among reefs were correlated with differences in depth, including a progressive turnover in species. Depth affected the functional traits of nearshore reef fish. Trophic breadth decreased with depth; carnivores and planktivores increased with depth, whereas herbivores decreased with depth. Smallsized fusiform fish dominated on the shallowest reefs. In summary, the present study demonstrated decays in biodiversity, from different perspectives, of reef fish with depth, which are connected with shifts in fish traits. [ABSTRACT FROM AUTHOR]

In this study, patterns in the taxonomic richness and composition of the fish fauna inhabiting Cymodocea nodosa seagrass meadows were described across their entire distribution range in the Mediterranean Sea and adjacent Atlantic Ocean. Specifically, the study tested whether there are differences in the composition of fish assemblages between those ecoregions encompassed by the distribution range of C. nodosa, and whether these differences in composition are connected with differences in bioclimatic affinities of the fish faunas. A literature review resulted in a total of 19 studies, containing 22 fish assemblages at 18 locations. The ichthyofauna associated with C. nodosa seagrass meadows comprises 59 families and 188 species. The western Mediterranean ( WM) Sea has the highest species richness (87 species). Fish assemblages from the Macaronesia-Canary Islands, the Sahelian Upwelling, South European Atlantic Shelf and the WM differ, in terms of assemblage composition, relative to other ecoregions. In contrast, the composition of the fish fauna from the central and eastern Mediterranean overlaps. There is a significant serial correlation in fish assemblage composition between adjacent ecoregions along the distribution range of C. nodosa. Dissimilarities in assemblage composition are connected with the geographical separation between locations, and the mean minimum annual seawater temperature is the environmental factor that explains most variation in fish assemblage composition. [ABSTRACT FROM AUTHOR]

The present knowledge of the marine phanerogams of the Canary Islands is poorly documented. Earlier studies of the marine phytobenthos along the Canarian coasts provides little information on seagrass ecosystems and their distributional patterns. This contribution summarizesthe available information about the three species reported for the islands: Cymodocea nodosa (Ucria) Ascherson, Halophila decipiens Ostenfeld and Zostera noltii Hornemann; and their distributional records is analized in relation with the main oceanographic and geomorphological conditions. Cymodocea nodosa and Halophila decipiens are present in shallow subtidal areas on diverse mobile substrata, whereas Zosteranoltii has been reported for intertidal communities in one eastern locality of Lanzarote Island, with historical records in Fuerteventuraand Gran Canaria Islands. At present, the latter species is not found in any of the mentioned localities and probably its has disappeareddue to anthropogenic activities (urban pollution, sediments disturbances). Most of the localities with seagrass communities are located in the eastern and southern coasts of the islands, always in shelteredareas, protected against Trade Winds. The vertical distribution of Cymodocea nodosa meadows ranges from (0.3) 2 to 35 m depth, whereas Halophila decipiens meadows are present between 6 to 40 m depth. [ABSTRACT FROM AUTHOR]