sentences:  The area is cited as one of two known breeding grounds for the humpback whale ("Megaptera novaeangliae") of the Northern Hemisphere.Humpback whales migrate annually from the North Sea to winter around Cape Verde from January to mid-May.The humpback whale population became limited due to severe overfishing during the 19th century and, although the total North Atlantic population of humpbacks had rebounded to more than 10,000 individuals by 1993, the Cape Verde population remained uncertain as of 2009.