Problem statement: Seahorse populations are declining globally as a result of overexploitation, habitat destruction and bycatch.  Conservation assessments, planning and controls were constrained by a lack of clarity on seahorse taxonomy: one name could apply to many different species, one species could be known by more than one name, or the species might be unnamed.

Methods: A review of the entire seahorse genus (Hippocampus) was undertaken. This involved locating/translating original species descriptions, then visiting 23 museums in 9 different countries to check type specimens, examine large numbers of other specimens from as wide a geographic range as possible, take morphological measurements and, where feasible, take material for genetic analysis. The data were used to identify species boundaries, distinctive features for the different species, and appropriate names for each.

Outcomes and impacts: The publication of a revised taxonomy of seahorses and identification guide enabled communication among researchers and conservationists and led directly to conservation assessments (e.g. IUCN Redlist assessments) and species-specific international trade controls (e.g. through listing on Appendix II of CITES, the Convention on International Trade in Endangered Species of Wild Flora and Fauna).  The CITES listing was a landmark for marine species of commercial importance that has led to similar constraints on trade in other species.

The study has also stimulated additional research on seahorses around the world, including the description of new species, the compilation of information on each species (such as distribution and population status) and genetic studies of connectivity among populations thereby furthering conservation efforts at local and regional levels.

Lessons: Updating and clarifying seahorse taxonomy was critical to the implementation of effective conservation measures including new controls of trade. The new identification guide has allowed the status of seahorse populations to be reliably assessed.