Relación de la densidad e intensidad de pastoreo de los peces herbívoros (Scaridae y Acanthuridae) con las macroalgas en el Occidente de Cuba

The fish families Scaridae and Acanthuridae are herbivorous that control algal growth on corals. Their exclusion due to illegal fishing and coastal development quickly leads to the dominance of macroalgae on the reef. To estimate the density and intensity of grazing of Scaridae and Acanthuridae and their relationship with macroalgae cover, two terraces were selected in the Guanahacabibes National Park (PNG) and one in Havana (LH), the latter with high anthropic degradation. Video-quadrants of 1 m2 were used to obtain the density of fish (individuals/m2) and grazing intensity (bites/5 minutes*m2) and quadrants of 25x25 cm for the relative abundance of macroalgae. Ten species were identified, Scaridae predominated in PNG and Acanthuridae in LH. The loss of Scaridae in LH implies that Acanthuridae represents an excess of a functional group that does not provide the bare substrate for coral recruitment. There was a strong positive correlation between the density and intensity of grazing of Scaridae with Halimeda, since in PNG this alga is favored and constitutes a recurrent and efficient food for Scaridae. In LH, eutrophication bioindicator algae such as Stypopodium predominated and only showed a positive correlation with Acanthuridae. These fish consume the epiphytes on Stypopodium, and their grazing rates are higher, which contributes to the cultivation of turf algae, strong competitors for space with corals. Hence the importance of presenting more equitable communities with different functional groups of herbivorous fish that contribute to a more effective control of macroalgae.