Sei and Fin Whales
The sei whales have been protected since the imposition of a 1979 ban on sei whale hunting from the International Whaling Commission. The population of these whales suffered greatly, with as many as 20,000 individuals harpooned and killed in 1964 and 1965 alone.
The fin whale also saw its numbers decline due to being hunted by countries such as Norway, the United States, Russia and Japan. The fin whale is the second largest whale in terms of sheer size and as such became a magnet for whalers seeking to make money by killing these whales for its blubber, baleen and the barrels of oil manufacturers could make from them. The fin whale fell victim to whalers seeking to exploit its meat and oil, with almost 29,000 killed in the early part of the 1960s. Protected since 1976, the fin whale has rebounded somewhat with as many as 100,000 now existing.
With some specimens as long as 100 feet and weighing 150 tons, the blue whale has the title of largest animal to ever live. Its size did not stop the whaling fleets of the various nations of the world from hunting it and the species neared extinction as whalers slaughtered them for their meat, baleen and oil. The blue whale received a break when a 1966 ban on hunting it came from the International Whaling Commission and it remains a protected species. According to the Antarctic Connection website, there may have been as many as 200,000 blue whales living in the entire world's oceans before the ban. Estimates now place the blue whale population at perhaps 11,000 whales.
The right whale obtained its strange name because it lacked speed, had plenty of blubber and oil and floated after it was dead. This made it the "right" whale to go after and was easy pickings for whalers in the early portion of the 19th century. This brought the right whale into such peril that despite having over 50 years of protection the whale has yet to recover in numbers.
Other Baleen Whales
The humpback whale--is the target today of friendly whale watchers but in previous decades it was the target of profit-seeking hunters--exists in only a fraction of its former abundance. As few as 20,000 are left after heavy hunting which eventually gave rise to a 1963 ban on persecuting the species.
The bowhead whale, a creature of the northern polar oceans, had an estimated population of 50,000 at one time that dropped to around 3,000 by the 1920s.
The Eskimos that hunt the Bering, Beaufort and Chukchi Seas harvest a small quota of bowfin whales for their own sustenance and this hunting is under close monitoring from such agencies as the Alaska Whaling Commission.
The gray whale had some of the earliest protection from hunters, with a ban in the 1930s helping this depleted species.
The sperm whale had the misfortune of being a source of ambergris, a substance that was a vital ingredient in perfume. Even the sperm whales' teeth worked against it as whalers prized them since they resembled ivory and people could carve elaborate patterns on them.
The 16-foot long beluga whale, a white whale of northern oceans, has thick skin that people tan and turn into leather. This use led to its becoming an endangered species.