Kai Wulf of the Saba Conservation Foundation reports on a recent research diving expedition on the Saba Bank:
From November 12th to 22nd , a team of eight scientists and conservation practitioners from Holland, Martinique, Bonaire and Saba came together on Saba for a mapping expedition to the Saba Bank. The expedition forms part of a joint project called CARIBSAT, between Martinique, Saba and Bonaire, to test a way to use satellite images to map the life on the bottom of the ocean. Both Bonaire and the Saba Bank need a good map of bottom life, showing different types of coral reefs, seaweed fields and sand bottom. In Martinique a detailed map was made a few years back, which was then compared to satellite images showing various colors reflected back from the bottom, which can be translated into corals, seaweeds, rocks and sand. Once this translation was made for Martinique, it could in theory also be applied to satellite images from other areas such as the Saba Bank, providing a map of the bottom. To ensure that this map resulting from satellite imagery would in fact be correct, the expedition went out to the Saba Bank to get video imagery of as many parts of the Bank as possible and measure the exact spectrum of light reflected back from the bottom. A total of 200 camera “drops” were made, lowering a camera from the boat to film a few tens of meters of the bottom, while measuring the light both at the bottom and at the surface. A number of dives were also made to film longer video transects, in order to carefully describe everything growing on the bottom. The dives were also used to count lobsters, conch and fish species.
This same exercise will also be undertaken on Bonaire, which has much shallower coral reefs and a different bottom structure. Once al the work has been analyzed it will result in a map for the Saba Bank and for Bonaire that will show various types of marine habitats.
The scientists expressed concern for the amount of dead coral reef they found at many places, presumably killed as a result of the 2005 Caribbean wide coral-bleaching event, attributed to global climate change. They also noted a paucity of fishes.
Get more information at the Dutch Caribbean Nature Alliance blog.