This guide is intended to help with the provisional identification of the first dorsal fins of five shark species:
. oceanic whitetip
. porbeagle
. scalloped hammerhead
. smooth hammerhead
. great hammerhead

The guide focuses on dried, unprocessed first dorsal fins because these are the most easily identified of the traded fins for these species.

In law enforcement and national border customs situations, this tool could provide probable cause to hold questionable fins, so that expert opinion could be sought or genetic testing could be conducted to confirm the field identification.

The five species covered by this guide are globally distributed, large-bodied and their fins are traded internationally in large numbers.  Four of the species have at least one population listed as Endangered or Critically Endangered by the International Union for Conservation of Nature (IUCN).  In addition, four of the species are subject to conservation and management measures in one or more regional fisheries management organizations.  All of these species have also at some point been proposed for inclusion on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

More than 500 dorsal fins from over 40 shark species were examined in developing this guide. Although there are more than 450 species of sharks, most of them (65%) are small-bodied (less than 1 meter in length as adults) and their dorsal fins are too small to be confused with the dorsal fins from the large-bodied species covered in this guide.   We suggest caution when using this guide to identify fins less than 10 cm across the base.  Only the fins of very young oceanic whitetip, porbeagle and the three hammerhead sharks would be that small.