Northern right whale
 
   
   

Eubalaena glacialis

Names

Azores : Raituel - POR : Baleia franca - ITA : Balena franca Boreale - SPAIN : Ballena franca - GB : Northern right whale - GER : Glattwal - NEDER : Noordkaper - NOORS : Liljehval - DEENS : Svarthval - JAP : Semi kujira

Biology

Adults' average size is 15 m, but they can reach a maximum length of 18 m. Weight varies from 30 to 80 tons. Females are larger than males and bear a single calf every 3 to 6 years. Gestation lasts about 1 year. Newborns are about 5 m long and they weigh a ton. They can remain with their mothers for as long as 2 years. The right whales' body is rotund and is dark in colour. The head is large and they have a series of callosities on the rostrum and on the chin and lower lips that are usually infested with parasites. The upper jaw has 220 to 290 pairs of baleen plates. They do not have ventral grooves. They feed exclusively on plankton such as copepods, krill and crustacean larvae. They can live for up to 40 years. The songs of these animals have frequencies that can vary as much as 0.05 to 0.5 kHz, and there are times when they can reach 2.2 kHz.

Observation

The whalers gave the common name of "right whale" to this animal because it was easy to hunt. In fact, perhaps due to this characteristic, they were almost exterminated, and today there is only a relatively small group of a few hundred of these animals in the western North Atlantic. This species seems to have practically disappeared from the eastern North Atlantic. Recent observations (December 1993) near the coast of Coru-a (Spain) seem to indicate that this species may recover from the whale hunting era and eventually re-colonise this region of the North Atlantic. Since the beginning of Espaço Talassa's activities, we have not been able to observe any animal of this species in the Azores; neither have we received any report of their presence in these waters. They are slow and heavy swimmers (speeds of about 2 to 3 knots) and they are presently found in small groups of 2 to 3 individuals. Their average dive lasts for about 5 minutes, but if disturbed they can remain submerged for 30 minutes. Their blow is up to 3 m high, slightly tilted forward and seen from behind it appears mostly as an open V-shape. This species is very friendly, curious, and it easily permits close approximation.

Cetaceans in the Azores