There is no monitoring or reporting framework for the global aquarium trade. This means that the best source of quantitative data are the wholesale import and export companies who link the supply and retail ends of the business. As a matter of routine business practice companies keep records of their sales, either as paper copies of their invoices or on company computer databases. The exact nature of these records varies, but all record the quantity of any individual species bought or sold, the date of each transaction and the source or destination of the shipment. Company sales records are therefore an excellent source of data on marine aquarium species in trade, and the only source for species not recorded under any other process (e.g. CITES). UNEP-WCMC and MAC have established good working relationships with such companies from all around the world. They have provided us with access to their sales records which are the core data in GMAD. These data have been through a careful and methodical period of data conversion (e.g. paper based records have been computerised) and formatting (e.g. data from different electronic systems have been placed into a single standardised format). Data from 45 representative wholesale exporters and importers of marine aquarium species have been harmonised by this process into a single Global Marine Aquarium Database. GMAD is now a legacy database, with the project having ended. Species+ and the CITES Trade Database (see 'related resources' below) both which provide additional, up-to-date information on species trade.