North atlantic right whale
Other names : Northern right whale, black right whale, bone whale, tube whale, Biscay whale, Biscayan right whale
Suborder : Baleen whales (Mysticeti)
Length : 10 to 15 m, up to 17 m
Weight : 30 to 60 t
Social behaviour : Solitary or in small groups
Life expectancy : Probably up to 80 years
Dive time : 6 to 8 minutes, up to 60 minutes
Observations : Occasional in the Gulf of St. Lawrence In the summer of 1998 at least two individuals visited the Estuary.
Global range : Northwest Atlantic, occasional incursions farther east
Global population : Less than 500 individuals
Status in Canada : Endangered
A small population of slow-moving, plump whales
With a critical threshold of a population estimated at less than 500 individuals, this species is the most threatened in the world due to the intensive hunting that had been practised for centuries. Today, every birth represents a glimmer of hope for its survival. This curvaceous whale, with its enormous head covered in outgrowths and its low responsiveness to passing boats, surprises us with its aerial behaviours and group dynamics.
Population, range and habitat
In the St. Lawrence
From July to September, the right whale frequents the shallow coastal waters of the St. Lawrence. Observations remain exceptional, however, even if they have been more regular since 1995. Indeed, some thirty individuals were photographed since that year, most often in the southern part of the Gulf, off the coast of Percé in the Gaspé. Some return year after year, seemingly adopting this region. Since 1998, more and more observations have been reported in the Magdalen Islands, Chaleur Bay, the Lower North Shore and the Estuary.
Highly frequented areas in summer are found in Canada and the United States: the Bay of Fundy and Scotian Shelf, as well as the Gulf of Maine and Cape Cod. Between October and April, North Atlantic right whales migrate south along the East Coast of the US. Pregnant females return to their winter calving grounds off the Florida and Georgia coasts.
In the world
The right whales of the St. Lawrence belong to the North Atlantic population, which is particularly present in the northwest, while the population of the northeast sector is probably extinct. In 2011, the North Atlantic Right Whale Consortium estimated the North Atlantic population at 490 individuals. North Atlantic right whales congregate in regions where food is abundant due to various oceanographic phenomena (thermal fronts, topography and upwellings) and in bays serving as shelters for females accompanied by their calves (Bay of Fundy). Southern right whales and North Pacific right whales are separate species.
The Northwest Atlantic population of the North Atlantic right whale was assessed in 1980, 1985, 1990, 2003 and 2013 by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), which determined its designation to be “endangered” each time. Despite the end to hunting in the 1930s, the North Atlantic right whale does not seem to have recovered. In 2010, the size of the population was estimated at 468 individuals, including 122 to 136 adult females. Between 1991 and 2007, 50% of all mortalities in this species were caused by collisions with ships. Although measures have been implemented in Canada and the United States to reduce such collisions, accidents still occur and shipping traffic is expected to increase considerably in the species’ range in the coming decades. What’s more, adult females seem to be more prone to ship strikes than males. Also, over 75% of individuals have scars attributable to incidental catches in fishing gear.
The North Atlantic right whale is listed in the International Union for Conservation of Nature’s (IUCN) Red List and under the American Endangered Species Act. Lastly, this species appears in the List of threatened or vulnerable species in Quebec under the Act Respecting Threatened or Vulnerable Species.
North Atlantic right whales are skimmers that can feed in deep waters or at the surface. They feed on zooplanktonic crustaceans such as copepods and occasionally krill. They sometimes feed in groups.
On the surface
Right whales spend a great deal of time at the surface and are very slow swimmers. Their low responsiveness to passing boats is an important factor in their mortality. But their aerial feats are impressive: they leap out of the water and land loudly on their back or belly, or slap the surface with their tail and pectoral fins. With their head pointing vertically out of the water, they sometimes spy on boats, a behaviour known as spyhopping. They can also let their head drift down and their tail rise up out of the water. They generally raise their tail when they dive.
Their dives last between 6 and 8 minutes, but can reach up to 60 minutes. Their prey are mostly found within the first 100 m or so below the surface, although they can dive as deep as 200 m.
Rather solitary, they may be seen swimming in pairs or in small loosely knit groups of about 10 individuals, and sometimes even up to 50. Sexual behaviours (fondling, rolling) are observed year round, i.e. outside of the reproduction periods. At the surface, multiple highly dynamic males may jostle one another in pursuit of 1 or 2 females.
Right whales emit essentially low-frequency vocalizations (below 500 Hz): grunts, squeaks, percussive sounds and some high-pitched sounds between 1500 and 2000 Hz. The purpose of these sounds is poorly understood. They appear however to be used for communication and the social life of groups active at the surface.
Sexual maturity is reached between the ages of 5 and 10 years for both sexes. Mating and calving take place between November and February. A female may mate with several males in succession. The size of the testicles (the largest in the animal kingdom, occasionally exceeding 900 kg) suggest that males seeking to inseminate a female engage in a sort of sperm competition. Gestation lasts about 12 months. Nursing lasts between 6 and 7 months, and sometimes up to a year and a half.
About scientific research
Photo-identification is performed based on the pattern of the parasite-covered skin growths that every right whale has on its head. This long-term program is critical for estimating the population. In late 2007, the group of researchers working on this population, the North Atlantic Right Whale Consortium, qualified its renewal rate as “modest”. The species is struggling to recover due to mortalities caused by collisions with boats and incidental catches in fishing gear. Despite the conservation measures taken in Canada and the United States, other causes may hamper its recovery: poor genetic diversity, disease, contaminants, reproductive problems and food resource depletion.
In the news
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