Beginning in 1996, CSA International, Inc. (CSA) developed a series of options for biologically enhancing a newly created salt water lagoon in the Berry Islands, Bahamas. Following site visits made to assess conditions within the lagoon, possible courses of action were outlined and a number of options were presented. These potential options included transplanting various locally-procured stony corals, soft corals, and sponges onto large carbonate rock structures placed within the lagoon.
The lagoon was formed following the dredging of an approximately 5-acre, landlocked, shallow hypersaline pond on Alder Cay to a depth of 2 to 3 m. Two entrance channels were cut after the removal of muddy sediments from the pond, allowing tidal circulation through the basin. Approximately 300 carbonate boulders (ranging in size from 1 to 3 tons) were then positioned within the lagoon, creating 29 individual rock structures as a base habitat for corals and sponges.
Heavy wire mesh fences were erected across the two lagoon entrance channels to prevent large predator access and to retain introduced fishes. Nearly 1,700 stony corals from 26 species, more than 2,300 soft corals from 18 species, and approximately 100 sponges then were transplanted onto the rock structures over a 2-year period. Following the initial transplantation, large numbers of reef fishes were added to the already existing fish population of the lagoon.
A monitoring program was established to measure the effectiveness of the project, and CSA scientists conducted annual monitoring surveys over a period of 5 years. The health, growth, and survival rates of corals on structures within the lagoon were compared to those of corals on adjacent hard bottom and reef areas selected as reference sites. Survival rates varied, with corals in areas of higher water movement exhibiting up to a 90% survival rate. Most coral mortality was associated with direct impacts of Hurricane Floyd, which passed over the cay, over-washed the lagoon basin, and buried nearly a third of the rock structures and corals with sediments.
The lagoon was formed following the dredging of an approximately 5-acre, landlocked, shallow hypersaline pond on Alder Cay to a depth of 2 to 3 m. Two entrance channels were cut after the removal of muddy sediments from the pond, allowing tidal circulation through the basin. Approximately 300 carbonate boulders (ranging in size from 1 to 3 tons) were then positioned within the lagoon, creating 29 individual rock structures as a base habitat for corals and sponges.
Heavy wire mesh fences were erected across the two lagoon entrance channels to prevent large predator access and to retain introduced fishes. Nearly 1,700 stony corals from 26 species, more than 2,300 soft corals from 18 species, and approximately 100 sponges then were transplanted onto the rock structures over a 2-year period. Following the initial transplantation, large numbers of reef fishes were added to the already existing fish population of the lagoon.
A monitoring program was established to measure the effectiveness of the project, and CSA scientists conducted annual monitoring surveys over a period of 5 years. The health, growth, and survival rates of corals on structures within the lagoon were compared to those of corals on adjacent hard bottom and reef areas selected as reference sites. Survival rates varied, with corals in areas of higher water movement exhibiting up to a 90% survival rate. Most coral mortality was associated with direct impacts of Hurricane Floyd, which passed over the cay, over-washed the lagoon basin, and buried nearly a third of the rock structures and corals with sediments.
