[The feeding activity of herbivorous fishes and their impact on coral reefs with different levels of anthropogenic degradation].

The feeding activity of three herbivorous fishes (Sparisoma viride, Scarus iserti and Acanthurus coeruleus) and its impact on two coral reefs were studied during the dry (February) and rainy (August) seasons of 2006 in Cuba. One of the reef stations is at the "Acuario" dive point in the Guanahacabibes National Park, and is relatively pristine. The second one is located at the north coast of Havana City facing the Instituto de Oceanología (IdO) and is subject to pollution and fishing pressures.

[Changes in fish communities of coral reefs at Sabana-Camagüey Archipelago, Cuba].

A comparison of fish community structure in the Sabana-Camagüey Archipelago (1988-1989 and 2000) using visual census surveys (eight belt transects 2x50 m in each site) suggests a notable decrease on species richness, and a two thirds reduction in fish density and biomass on coral reefs. This decrease in fish populations may be related to the alarming decrease of scleractinian coral cover, and an enormous proliferation of algae, which currently covers 70-80% of the hard substrate, impeding the recovery of corals and other benthic organisms. High coral mortalities occurred between the study periods, which correlate with the high temperatures caused by the ENSO events of 1995, 1997 and 1998.