What threatens the humpback whale?

Answer 1

Humans. Man has severely affected humpback whale populations by killing them for years. By the 19th century, many nations (USA in particular), were hunting the animal heavily in the Atlantic Ocean, and to a lesser extent in the Indian and Pacific Oceans. This widespread hunting sharply reduced whale populations.

It is estimated that during the 20th century, at least 200,000 humpbacks were taken, reducing the global population by over 90%, with North Atlantic populations estimated to have dropped to as low as 700 individuals. To prevent extinction, the International Whaling Commission banned commercial humpback whaling in 1966. By that time the population had been reduced to around 5,000. That ban is still in force