EN

Endangered

A1ad

3.1

The cause of the population reduction in this species (commercial whaling) is reversible, understood, and is not currently in operation. For this reason, the species is assessed under criterion A1, not under A2, A3 or A4. The global mature population is estimated to have declined by about 80% over the last three generations (Figure 1 in linked PDF document). This is supported by observed declines in abundance in several regions. Most of this decline is attributable to the southern hemisphere. While a higher intrinsic rate of increase than that given in Table 1 (in linked PDF document) may be possible and could result in a less threatened category, a precautionary approach is to use the value given in Table 1, which, based on the available data, is plausible for sei whales, particularly given the absence of direct evidence of any increase in the population.