"Among the fishermen, the whale regularly hunted for oil is indiscriminately designated by all the following titles: The Whale; the Greenland whale; the black whale; the great whale; the true whale; the right whale.
In fact, there was indeed a difference between the two - Melville's "Greenland whale", or "Greenland right whale", was in fact the modern-day bowhead whale, Balaena mysticetus.