respond to environmental triggers. Silurids (another catfish family) follow next with three
species (9% of the species belonging to the family), then cyprinids with nine species,
representing 3% of the 285 species of this family found in the Mekong (Figure 4).
Thus among the 18% of migratory fish for which the triggers have been documented,
catfishes, with 15 species listed, are by far the group most sensitive to triggers, particularly
bearing in mind that many of these species are sensitive to several triggers at once (see
Annex 1 for details).