Although commercial hunting of whales began in the 18th century, the majority of reported kills took place between 1950 and 1980 when harpoon guns became more widely used. As a result of commercial whaling, the humpback whale herd around New Zealand and Australia was exterminated by 1966. Six years later, the sei herd in the Indian Ocean was destroyed, and by 1975 the sperm whales north of Hawaii had all but vanished. Hunting of the right whale had been banned in 1930, and the blue whale in 1965.
Despite the 1986 moratorium against whaling, a process of "scientific whaling" has been continued by Norway, Japan and Iceland. This is stated to signify the killing of whales to assess their age and sex so that stocks can be calculated. The whales are nevertheless processed in the usual way so that there is strong suspicion that the term is merely a cover-up for normal commercial whaling practices. To compensate for the reduction in supplies of whale meat, the hunting of porpoises has increased since 1986. Thus in three years, Japanese fishermen have killed 70% of the estimated population of 105,000 Dall's porpoises in Japanese waters. It was revealed in 1994 that the former Soviet Union had continued to systematically hunt whales since 1977, selling the meat to the Japanese for hard currency. In the course of the previous 40 years, they had systematically grossly underreported catches by such large amounts that the International Whaling Commission is forced to recalculate all its statistics and recovery rates for the great whale species.
An estimated 500,000 small whales, porpoises and dolphins are killed annually by hunting or through being caught in nets. Most evident is the destruction of whales and dolphins, although the latter are often killed inadvertently in the process of netting tuna or through the use of drift nets.