Saba Bank; health status 2010. Cruise report
The main conclusion from this study is that the health of the reefs of the Saba Bank has deteriorated since the first observations in 1972, 1996, and 2002. The general impression is that the Bank is still recovering from the 2005 bleaching disaster, but there is not enough data to exclude other reasons (e.g. overfishing, anchor damage, hurricanes).
- In 1996, Meesters et al. estimated coral cover at 7 locations to lie between 60 and 90%. These percentages were nowhere observed this time. The best site visited had an estimated coral cover of around 50%.
- There is now a high cover of algae (mainly Dictyota spp. and Lobophora spp.) on the reefs of the Bank.
- The present absence of important grazers such as the black sea urchin are likely to slow down recovery.
- Fish numbers appeared to be lower than previously observed, though sharks were observed on almost every dive, indicating a still intact food chain. The low numbers of fish may be a seasonal effect, a result of the presence of predators, or a result of changes that followed from the 2005 bleaching event.
However, corals appear healthy and the reefs of the Saba Bank are probably slowly recovering to their previous grandeur.
- Very few coral colonies with diseases were observed.
- Some colonies were bleached as result of the seasonal high water temperatures, but there appeared to be almost no mortality among these bleached colonies.
Begin to regularly monitor the health of the Bank’s coral reefs and the impact of human activities such as fishing as soon as possible (permanent video transects are planned to be installed in 2011 at a number of sites on the Bank).