Beluga 500 kg. The Sea of Azov. 1956. The Azov beluga is a subspecies that is on the verge of extinction. It is included in the Red Book of the Russian Federation. Azov beluga is the fastest growing and early maturing intraspecific form of beluga. It reaches a length of 4.6 m and a weight of 750 kg. It has 2 forms: winter and spring. Females mature at 16-17 years old, males at 12-14 years old. Distribution: the Azov Sea basin. It is found in the sea and rivers where it comes to spawn (the Don River, much less the Kuban River). Fishing: in the past, the most valuable commercial fish. In the 20th century, the maximum catches were reached in the late 30s and reached 1000-1200 tons. Protection measures: since 1986, azov beluga fishing in the Azov has been prohibited, only catching producers for artificial breeding is allowed.