 In the case of some species, in particular the blue whale (which Ishmael calls the "sulphur-bottom whale"), very little was known at the time.The classification is thus heavily weighted toward whales hunted for oil and other uses, and presents a picture of the common knowledge of whales at the time of the novel.Since Melville presents the study within a fictional context, voiced by a fictional character in the narrative, it is arguable whether or not Melville intended the classification as a serious scientific contribution.