Boring Sponge (Cliona spp.) Population Surveys on Coral Reef Sites in Discovery Bay, Jamaica
E. Markowitz and G. Taylor
The boring sponges (Cliona spp.) bioerode live coral and coral rubble by excavating the calcium carbonate from the substrates by chemically etching it away (Holmes 2000). They are known to grow in higher abundances in areas that are experiencing stress. An analysis of species composition showed that distances, and depths within the reefs, on the back reef, and areas not in the reef zone had an effect on clionid community composition (Holmes 2000). Sponge abundance is more greatly effected by factors affecting the reefs as a whole (Holmes 2000). A local anthropogenic stress to coral reefs is believed to be the Bauxite mill in Discovery Bay because of the small sediment discharge and human activity in the area. The boring sponge and coral percent coverages are hypothesized to reflect their proximity to the site. To assess a proxy for stress, sediment size, water clarity, coral percent coverage, boring sponge percent coverage, and coral species richness from each site were analyzed. Sites down the long shore current from the Bauxite mill included Discovery Bay lagoon, Blue hole within the lagoon, and various sites on the Discovery Bay reef crest, sites up the longshore current from the Bauxite mill, and Columbus Park. Sites within the lagoon were at 1.524m (5 feet), Blue hole was taken at 4.572m (15 feet), and all other sites were taken at 9.144m (30 feet). Sites were analyzed for percent coverage by taking photos of a half meter quadrats on a 10 meter transect line. Photos were later analyzed with Coral Point Count with Excel Extensions 4.1 (CPCe 4.1) for boring sponge and coral percent coverage. Sediment will be analyzed for size through ImageJ 1.47v. All samples were analyzed from 17 January 2014 to 21 January 2014. Boring sponge (Cliona spp.) populations will be higher at sites with smaller bottom sediment particle size, lower coral coverage and lower coral species richness. It was found that very small amounts of boring sponge were found in Columbus park where abundances of coral were expected to be lower while boring sponge abundance was expected to be higher. Further analysis and studies can be done to determine the reason for low boring sponge abundance with low coral abundance.
GraceAnne reachcing into the tool bag for bottles to collect a sediment sample at Columbus Park.