 After blue, humpback and southern right (the USSR took 3,368 southern rights and reported only 4) whales were depleted, the shift began to sei whales.While seis at the time were still largely intact due to being smaller and less valuable than blue and fin whales, commercial whaling beginning in 1962–63 was intense.Catches of sei whales continued to climb until 1966–67, when 3,500 were killed by the three Soviet fleets, particularly "Sovetskaya Rossiya".