Since the establishment of the Flanders Marine Data and Information Centre (VMDC) we have been working on a central species register, ‘Aphia’, to support all other biological applications of the data centre. Taxonomic information including synonymy and higher classification is stored in a single relational database. At the moment, Aphia holds around 20,000 taxa for a geographical range roughly corresponding to the North Sea, including adjacent areas such as estuaries and the English Channel. The information is primarily retrieved from authoritative publications, but has also come from experts and other databases (with a total of 1,200 sources). We recently started screening grey literature and historical data from publications dating back to the mid nineteenth century. Some attempts have been made recently (Cattrijsse and Vincx, 2001; Kerckhof and Houziaux, 2003) to provide a picture of Belgium’s marine biodiversity. However, none of these were fully satisfactory as no attempt was made to list all the information that has been recorded by our prominent and most notable Belgian taxonomists (a.o. Van Beneden, Leloup, Gilson, Adam,…) in the last 150 years till the intensive sampling campaigns from the 1970s on. Bearing in mind May’s (1988) pertinent question of how many species there are on earth, we are far from knowing of what exactly occurs and was found in the North Sea and along our coasts. Last year the number of taxa stored in our register increased with 32%. Of the newly entered species, 27% are redundant names that were relegated to synonymy. We were still able to add 33% valid species names (reaching a total of ~8,150 valid species) with no less than 77% increase for species mentioned from Belgian marine waters. The total for Belgium now stands at 2,700 valid species. Clearly, our mission is not accomplished yet, and this is still very much a work-in-progress that requires more input, quality control and close collaboration with the experts in the field. May be within a few years we’ll have a full scope ...