The IUCN Red List measures the change of global diversity and acts to conserve that biodiversity through assessments of individual species and identifying and carrying out actions to address concerns. Species assessments evaluate the chances of extinction in the foreseeable future based on past and expected future trends. They help to prioritize where action is most urgently needed and also to identify the major threats.
Collectively, the groupers and wrasses include almost 1,000 species, many of which are important commercially and relatively well-studied. To identify major threats to groupers, the International Union for Conservation of Nature (IUCN) Red List criteria were applied to all 163 species. Red List assessments show that 20 species (12%) risk extinction if current trends continue, and an additional 22 species (13%) are considered to be Near Threatened. The Caribbean Sea, coastal Brazil and Southeast Asia contain a disproportionate number of Threatened species, while numerous poorly documented and Near Threatened species occur in many regions. In all, 30% of all species are considered to be Data Deficient. Work by many GWSG members is addressing, in particular, the threatened species identified and we aim to also be able to assess Data Deficient species in the near future. For the wrasses, work continues but we have a particular focus on the Humphead (=Napoleon) wrasse because it is listed on CITES Appendix II.
The assessment procedure requires that each species be judged under 5 sets of criteria (A-E) that have been chosen to cover all scenarios that might increase a species' vulnerability to extinction. Each criterion will produce an assessment of the species that is (in order of most to least threatened) Critically Endangered, Endangered, Vulnerable, Lower Risk or Data Deficient. The most threatened rating that is obtained from any one of the 5 criteria is the one used to categorize the species. The 5 criteria in brief are "Declining Population" (A), "Small Distribution and Decline or Fluctuation" (B), "Small Population Size and Decline" (C), "Very Small or Restricted" population (D) and "Quantitative Analysis" (E) which uses techniques such as Population Viability Analysis (PVA). Most groupers and wrasses that have been assessed so far have received their most threatened rating from "Declining Population" (A).