The answer is subsistence. As recently as 1988, humpback whales were listed as endangered by IUCN. Populations have now recovered, due to the introduction of commerical whaling bans. There are still concerns about apparently discrete and small subpopulations of humpback whales, including those in the Arabian Sea, the western North Pacific, the west coast of Africa, and the South Pacific subpopulations in portions of Oceania.
Humans hunted humpback whales commercially for oil, meat, and baleen from the 17th to early 20th centuries. Humpback whales are still hunted in Greenland and by the Bequians of St Vincent and The Grenadines, for subsistence purposes, but only 1-2 per year are caught.