General Description Fin whales, the second largest creature on earth, are brown/gray in color with a prominent white underside marked with approximately 85 throat grooves that extend to the navel. The coloring on the underside of the jaw area is asymmetrical; the right side is white, while the left side is dark brown/gray. Coloration varies in each and every whale.
Internally, each portion of the jaw contains between 350-400 baleen plates. These plates have been described as hanging vertical venetian blinds that are frayed on the inner edges. They are able to strain food particles from the sea water. The main distinguishing feature of the fin whale is its prominent dorsal fin. This fin is approximately 60 cm long, strongly curved and placed well back on its long and slender body.
The fin whale’s average length ranges between 19-20 meters for males and females alike. The mean weight of a fin whale is 70, 000 kg. Their life span has been estimated at approximately 60 years wherein full physical maturity is reached between 25-30 years.
Fin whales have a tall “blow” jet of moisture which comes from one nostril located on the head. This stream of water can travel 10 m in the air. Fin whales expel moisture after partaking in long and deep dives.
Geographical Distribution and Habitat Requirements Fin whales are found in the Atlantic, Antarctic, Pacific, Indian and Arctic oceans as well as in the Black and Mediterranean seas. This species of whale is not common in the tropics.
Fin whales migrate seasonally. During the spring and summer months the fin whales can be found in cooler high latitude oceans, like the Atlantic. These creatures have most often been sighted in the Bay of Fundy where they are evenly distributed around the mouth of the bay. Throughout the winter months these animals live in warmer waters of a lower latitude.
General Biology Although seasonal variations have been noted in the diet of the fin whale, it basically dines on planktonic animals, crustaceans, squid and fish, namely herring. If these are not available another food source such as shrimp like crustaceans can be used.
Throughout the winter months, while living in the warmer more southerly waters,the whales consume little. During the summer months, while living in the more northerly waters, the whales feast on krill-euphausiid shrimp and small schooling fish, like anchoives.
Fin whales are mostly monogomous but can also be deemed gregarious, as they sometimes travel in pods of 6-7 members. Breeding in fin whale populations occurs during the winter months in the lower latitudes when they reach sexual maturity, (approximately 10 years of age). Mating activity is thought to occur chiefly in December and January. Gestation lasts 11-12 months, at which point one calf is born. Infrequently, multiple birth occur, these can yield up to 6 calves. Upon underwater birth the calves are 6.5m long and are able to rise to the surface.
Fin Whales are one of the fastest cetaceans in the ocean reaching cruising velocities of over 35 kilometers per hour. These aquatic, diurnal animals can reach depths of 230 meters, stay under for approximately 15 minutes and completely lift their bodies out of the water.
Conservation Fin whales have been heavily hunted over the last century. The numbers available for harvest between 1946-65 were greater than 10,000 per year. This predation pressure was not lessened until the International Whaling Commission decreases quotas in the mid 1970’s. Luckily by 1985, the whale quota was decreased to zero. At present the IUCN lists the fin whale as an endangered species which means that is has encountered a decline of at least 50 % over the last 10 years. It is not critically endangered but it has a very high risk of extinction in the wild.