Why are Humpback Whales Endangered?

Why are Humpback Whales Endangered?

By 18th century, the commercial value of humpback whales increased and that made them a preferred target for hunters.
 
During 19th century, many nations were hunting heavily humpback whales and the increasing sophistication of weapons caused a great decline in humpback whale population by the beginning of 20th century, reaching alarming levels as low as 700 individuals in the North Atlantic.
 
Reaching around 1966 a population worldwide as low as 5,000 individuals, the Whaling Commission issued a desperate ban on humpback whales to prevent extinction.
 
This protection has recovered the population from an historic 1,500 whales before the banning to around 20,000 individuals today.