Assessing the effects of parrotfish grazing and macroalgal competition on coral cover in the middle Florida Keys


Meeting Abstract

75.3  Tuesday, Jan. 6 10:45  Assessing the effects of parrotfish grazing and macroalgal competition on coral cover in the middle Florida Keys SMITH, K/M*; CHILDRESS, M/J; Clemson University kylie4@clemson.edu http://childresslab.blogspot.com/

Coral cover in the Caribbean has drastically decreased over the past several decades. Previous studies have found evidence of competition between macroalgal species and reef building coral species. Studies have also found that reefs with higher parrotfish abundance tend to have higher coral cover. These studies suggest that parrotfish graze on this competitive macroalgae, indirectly having a positive influence on coral health. In the middle Florida Keys, coral reef ecosystems have also experienced a decline in overall coral heath and cover. We conducted surveys of reef substrate composition and parrotfish density across fourteen reefs in the Florida Keys National Marine Sanctuary. Our results show no evidence for linear relationships between coral cover, macroalgae abundance or overall parrotfish abundance. However, we did find significant regional differences in coral cover and individual species interactions. The abundance of striped parrotfish, Scarus iserti, was positively correlated with coral cover while turf algae was negatively correlated with coral cover. Additional research is being done to better understand the dietary preferences of each species of parrotfish, as well as the competitive relationship between corals, turf algae, macroalgae, sponges and octocorals. By understanding the characteristics of sites where corals are currently most abundant, we hope to identify the conditions that are essential for successful coral restoration.

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