Utilization of smaller grouper species (Cephalopholis cruentata, Cephalopholis fulva, Epinephelus guttatus, Epinephelus adscensionis) densities as a coral reef health indicator
Serranidae, the grouper family, are common carnivorous fish that inhabit Bonaire’s coral reefs. Smaller grouper species are commonly spotted along the lower layers and crevices under the complex coral reef structure. These carnivores control population levels of lower trophic level omnivores (e.g. damselfish). Four smaller grouper species (Cephalopholis cruentata, Cephalopholis fulva, Epinephelus guttatus, and Epinephelus adscensionis) densities were used as indicator to evaluate current coral reef health on Bonaire. Maximum reef relief was estimated to evaluate for consistency in reef complexity across box transects. AGGRA fish methodology was used to survey densities of targeted Serranidae species. Recorded densities were compared to previously reported grouper densities from 2003 to 2011. A significant increase in density for C. cruentata (9.58 individuals/100 m2 ) and E. guttatus density (4.17 individuals/100 m2 ) was found since 2011. E. adscensionis and C. fulva densities were found to be consistent since 2003. Overall, a healthy coral reef was supported by the evidences of an increase in C. cruentata and E. guttatus since 2011. This increase in Serranidae density is controversial to commonly proposed competition between lionfish and native carnivores. Lionfish removal efforts are hypothesized to positively affect smaller Serranidae density, leading to a higher density in 2013. A biocontrol mechanism is proposed as a long-term solution following lionfish invasion. Future directions are discussed in regards to maintaining a resilient Serranidae population on Bonaire’s coral reef by establishing marine reserves and continued removal of Pterois spp. individuals.