Finback Whale - Balaenoptera physalus


The Finback or Fin whale is the second largest animal species alive on earth today. Shaped similar to the Blue whale but more streamlined the Fin whale can achieve a length of 70-75 feet and top out at a weight of 75 tons or about 150,000 pounds. The Finback fell prey to the whalers, but since the moratorium on the killing of this species was set in 1966, the Finback has made a steady recovery. It is believed that around 100,000 individuals are alive today. The Finback is very difficult to identify individually and therefore not an easy species to study. It lacks pigmentation that is discernible. Individuals are dark and occasionally have a blaze or chevron on their right side between the dorsal fin and head that is photographically distinct. Other that this, the Finback has a large dorsal fin (hence the name Fin whale) and on about one in four individuals the trailing edge of this dorsal fin is noticeably nicked or scarred, and in this case individuals also can be identified, though over time these marks may change shape or increase in size. The Finback rarely ever lifts its tail above the water surface while diving thereby robbing the researcher of another possible source of individual identification, that being the pigmentation and shape of the lower or posterior side of the tail or fluke.

In the Sea of Cortez the Finback can be found in winter months almost every day by the trained researcher. It is believed that many Finbacks stay in the Sea of Cortez year round and indeed they have been documented in every month of the year. It is likely that some Finbacks found in these waters are migratory while others call these waters home. Cows with their calves are not uncommon in winter months and often with a hydrophone their vocalizations can be heard, low loud groans. Finbacks are fast swimmers, sometimes called "greyhounds of the sea". In the Sea of Cortez they are often encountered in small groups of 2-4 individuals. Their lower jaws are very white on the right side, and much darker on the left side, their undersides are quite white, and when they roll over this is startling in contrast to their dark upper bodies. From a distance the Finback emits a very tall blow or spout when exhaling and it is quite difficult to differentiate from that of a blue whale. Indeed many people have a difficult time identifying a Finback from a Blue whale.

Back to Marine Life