Definition: A taxon is Vulnerable when the best available evidence indicates that it meets any of the
criteria A to E for Vulnerable, and it is therefore considered to be facing a high risk of extinction in the wild.
Comment: "Small" is ambiguous. For details on "Small rivers" (e.g. the Salween river) see http://worldwildlife.org/biomes/small-river-ecosystems. This class will be replaced with a less ambiguous class.