Southern blue fin tuna have been released since 1959 using conventional tags. This is where the tag database has its origins and therefore a large amount of the data held in the database consists of conventional (dart) tags releases of this species in Australian waters. In recent times the data base has evolved to include many more species of pelagic and benthic fish, sharks and turtles. The advent of electronic tags, some with satellite and/or acoustic tracking ability has added to the complexity of the database. Not only do these electronic tags require additional fields for setup options before release, but also require tables to support the complex range of data retrieved from these tags. The data has been grouped into a number of projects. The purposes behind each such project are many and range from the collection of data required for population analyses (the estimation of mortality rates and growth rates), to the investigation of large and fine scale movements, feeding patterns as revealed by the use of ‘smart tags’. Also for many tagging programs there have been changes in tagging ability between skilled and novice taggers. Individual projects thus reflect these criteria so that each Marlin entry contains as nearly as possible a homogenous data set in terms of: 1. Species 2. Tag type 3. Taggers used, in particular the use of CSIRO or non CSIRO personnel 4. Period of coverage to ensure that particular variants of tag type were used 5. Specific project aims 6. Specific geographical area 7. Lead agency ( to ensure that appropriate permission is obtained before access to the data base is permitted) Thus all the species specific data contained in the CSIRO data base has been grouped into discrete Marlin metadata units. Tag data for a particular species may also be covered by multiple Marlin units. The CSIRO database manager has a full listing of the species numbers contained in all Marlin units. Species where more than 200 individuals have been tagged in individual or multiple projects are listed in the descriptive keyword section. Keywords: Tag, Conventional, Archival, Acoustic, Pop-Up, Satellite, Tuna, Swordfish, Shark, Pelagic Fish, Demersal Fish, Turtles.