The documentation for each IMMA includes a list of the qualifying marine mammal species that occur and that are fundamental to satisfying each criterion used in the IMMA identification. Supporting species are marine mammal species that occur within the IMMA but which are not fundamental to satisfying the criteria. Figure 2 shows the number of qualifying species listed for each IMMA. The majority were identified on the basis of one or two qualifying species.
Fifty-eight different marine mammal species have been used as the qualifying species for an IMMA. As shown on Figure 3, humpback whales (Megaptera novaeangliae), dugongs (Dugon dugon), Indo-pacific bottlenose dolphins (Tursiops aduncus), Sperm whales (Physeter macrocephalus) and spinner dolphins (Stenella longirostris) were the most commonly represented species.