Why is the kilo of Beluga caviar so extremely expensive?

due to the fact that this animal species is on the edge of extinction

It is a fairly old species that was isolated in the Caspian Sea bordering Iran and the former USSR, and because it is a slow reproducing animal, it is in heat for a long time, resulting in few animals, few eggs (caviar), and the species was not allowed to recover when they were exploited…