The Finback Whale is a species of baleen whale belonging to the RORQUAL family. It is the second largest species of whale, after the blue whale, and is also known as the fin whale. The scientific name for the Finback Whale is Balaenoptera physalus. The Sei Whale is another species of baleen whale belonging to the RORQUAL family. It is the third largest species of whale, after the blue whale and the fin whale. The scientific name for the Sei Whale is Balaenoptera borealis.