This survey was undertaken at the request of FAO in 1996. The evaluation is based upon a survey of the scientific literature, on unpublished data made available to us by several researchers or institutions, and on a questionnaire on biological and fishery data on shark sent out to national institutions. Because of the wide or cosmopolitan ranges of many species of sharks, and because of the lack of fisheries data, in most cases it was not possible to assess a species as a whole.
Much of the data used in this report is of Australian or of North American origin. This is simply a reflection of the effort spent in shark research and management in Australia and, in the last few years, in the United States.
As a survey of the status of all the shark species, this work can be considered only as a preliminary assessment, as it reflects our fragmentary knowledge of sharks and the paucity of fisheries data that was available to the authors. Many species are simply listed as being Category 1, corresponding to exploited species for which biological or fishery data are few or non existent. It is hoped that this preliminary assessment will encourage others to make the relevant data available to FAO for inclusion in future revisions.