Genetic diversity and connectivity of populations on the Saba bank

From 19-27 October 2013, IMARES (Wageningen UR) organized a research expedition to the Saba Bank, to investigate the ecological functioning of the Bank. The expedition is a follow up of a survey of the bank in 2011 and is part of the “The Saba Bank Research Program 2011-2016” initiated by the Dutch Ministry of Economic Affairs (EZ). The bank is the largest submarine atoll in the Caribbean Sea, spanning an area of 2200km2. It is a Marine Protected Area and is acknowledged by the Convention of Biological Diversity as an Ecologically and Biologically Significant Area. The project is part of the implementation of the Exclusive Economic Zone management plan for the Dutch Caribbean.

If the Saba Bank is to serve as a source of healthy larvae for the neighboring reefs, a key question is how populations of reef organisms on the bank are connected with populations in the region and in the Wider Caribbean. The aim of the current report is to investigate the health status and the population genetic structure of two common native benthic species, Xestospongia muta (giant barrel sponge) and Montastrea cavernosa (great star coral), and an invasive species, Pterois volitans (lionfish). With the aidof molecular techniques and species assessments, we aim to assess:

• the level of genetic diversity within the populations of two common benthic species (X. muta and M. cavernosa) on the Saba Bank;
• the degree of genetic connectivity between populations on Saba Bank and surrounding reefs, based on newly obtain genetic sequences and sequences obtained from GenBank from populations across the Wider Caribbean;
• the current density and health status of the populations of X. muta and M. cavernosa on Saba Bank.
• the genetic connectivity, population size and the dispersal direction of the invasion of the lionfish on the Saba Bank, in relation to the Eastern Caribbean populations.