The North Atlantic right whale (Eubalaena glacialis) is a baleen whale, one of three right whale species belonging to the genus Eubalaena, all of which were formerly classified as a single species. Because of their docile nature, their slow surface-skimming feeding behaviors, their tendencies to stay close to the coast, and their high blubber content (which makes them float when they are killed, and which produces high yields of whale oil), right whales were once a preferred target for whalers. At present, they are among the most endangered whales in the world, and they are protected under the U.S. Endangered Species Act and Marine Mammal Protection Act and Canada's Species at Risk Act. There are an estimated 356 individuals in existence in the western North Atlantic Ocean—they migrate between feeding grounds in the Labrador Sea and their winter calving areas off Georgia and Florida, an ocean area with heavy shipping traffic. In the eastern North Atlantic, on the other hand—with a total population reaching into the low teens at most—scientists believe that they may become functionally extinct in the next two decades. Vessel strikes and entanglement in fixed fishing gear, which together account for nearly half of all North Atlantic right whale mortality since 1970, are their two greatest threats to recovery.
Description
Like other right whales, the North Atlantic right whale, also known as the northern right whale or black right whale, is readily distinguished from other cetaceans by the absence of a dorsal fin on its broad back, short, paddle-like pectoral flippers and a long arching mouth that begins above the eye. Its coloration is dark grey to black, with some individuals occasionally having white patches on their stomachs or throats. Other unique features include a large head, which makes up a quarter of its total body length, narrow tail stock in comparison to its wide fluke, and v-shaped blowhole which produces a heart-shaped blow.
The most distinguishing feature for right whales is their callosities: rough, white patches of keratinized skin found on their heads. The right whale's callosities provide habitat for large colonies of cyamids or whale lice, which feed on the right whale's skin as these small crustaceans cannot survive in open water. The relationship between cyamids and right whales is symbiotic in nature but is poorly understood by scientists. Callosities are not caused by the external environment and are present on fetuses before birth. However, Cyamids near the blowhole have been linked to chronic entanglement and other injuries; their presence in this area has been used as measure of individual health in visual health assessments.
Adult North Atlantic right whales average in length and weigh approximately , they are slightly smaller on average than the North Pacific species. On each side of the upper jaw are 200–270 baleen plates. These are narrow and approximately long, and are covered in very thin hairs. The pectoral fin is long. The largest measured specimens have been long and .Whale and Dolphin Conservation, Species guide – North Atlantic right whale Females are larger than males.
Up to forty-five percent of a right whale's body weight is blubber. This high percentage causes their body to float after death due to the fact that blubber has a low density.
There is little data on their lifespan but it is believed to be at least 70 years, although individuals in species closely related to right whales have been found to live more than 100 years. Currently, female North Atlantic Right whales live on average 45 years and males 65 years. Age of right whales can be determined by examining their earwax postmortem. The oldest recorded whale was sighted between March 24, 1935 and August 13, 1995, and is thought to have been as old as 70 years. However, a 2024 study found that the average lifespan was only 22 years, with only 10% of individuals living longer than 47 years, presumably as a result of shortened lifespans due to commercial whaling.
Behavior
Surface activities
Aside from mating activities performed by groups of single female and several males, so called SAG (Surface Active Group), North Atlantic right whales seem less active compared to subspecies in southern hemisphere. However, this could be due to intense difference in number of surviving individuals, especially calves that tend to be more curious and playful than adults, and small amount of observations. They are also known to interact with other baleen whales especially with humpback whalesProvincetown Center for Coastal Studies. 2007. May 2007 . Retrieved on May 13. 2014 or bottlenose dolphins.Harbor Branch Oceanographic Institute. 2015. Julie ALBERT 11/19/14 North Atlantic Right Whales on YouTube. Retrieved on January 02. 2015
Vocalization North Atlantic right whales recordings are available online. Many effective automated methods, such as signal processing, data mining, and machine learning techniques are used to detect and classify their calls.M. Pourhomayoun, P. Dugan, M. Popescu, and C. Clark (2013). Bioacoustic Signal Classification Based on Continuous Region Features, Grid Masking Features and Artificial Neural Network. International Conference on Machine Learning (ICML).
Reproduction North Atlantic right whales are promiscuous breeders. They first give birth at age nine or ten after a year-long gestation; the interval between births seems to have increased since the 1990s, and now averages three to six years. Calves are long at birth and weigh approximately . The North Atlantic right whale's penis can reach at least in length.
Predation The only known predator of the North Atlantic right whale is the killer whale. There is one recorded case of predation.
Feeding Right whales feed mainly on copepods and other small invertebrates such as krill, pteropods, and larval barnacles, generally by slowly skimming through patches of concentrated prey at or below the ocean surface. Sei whales and basking sharks (sometimes minke whales as well) are in positions as food competitors and are known to feed in the same areas, swimming next to each other,O'Donnell E., 2012, Teacher at Sea – There's a Lot of Food in the Ocean and One More Whale to Feed!, National Oceanic and Atmospheric Administration, Retrieved on May 13, 2014 but there have not been any conflicts observed between these species.
Taxonomy
The whale's scientific name is Eubalaena glacialis, which means "good, or true, whale of the ice".
The cladogram is a tool for visualizing and comparing the evolutionary relationships between taxa. The point where a node branches off is analogous to an evolutionary branching – the diagram can be read left-to-right, much like a timeline. The following cladogram of the family Balaenidae serves to illustrate the current scientific consensus as to the relationships between the North Atlantic right whale and the other members of its family.
Another so-called species of right whale, the "Swedenborg whale" as proposed by Emanuel Swedenborg in the 18th century, was by scientific consensus once thought to be the North Atlantic right whale. However, the 2013 results of DNA analysis of those fossil bones revealed that they were in fact those of the bowhead whale.
Whaling
As the "right" whale continued to float long after being killed, it was possible to 'flense' or strip the whale of blubber without having to take it on board ship. Combined with the right whale's lack of speed through water, feeding habits, and coastal habitat, they were easy to catch, even for whalers equipped only with wooden boats and hand-held harpoons.
Basques were the first to commercially hunt this species. They began whaling in the Bay of Biscay as early as the eleventh century. The whales were hunted initially for whale oil, but, as meat preservation technology improved, their value as food increased. Basque whalers reached eastern Canada by 1530. The last Basque whaling voyages were made prior to the commencement of the Seven Years' War (1756–1763). A few attempts were made to revive the trade, but they failed. Shore whaling continued sporadically into the 19th century. It had previously been assumed that Basque whaling in eastern Canada had been the primary cause for the depletion of the sub-population in the western North Atlantic, but later genetic studies disproved this.
Setting out from Nantucket and New Bedford in Massachusetts and from Long Island, New York, Americans took up to one hundred right whales each year, with the records including one report of 29 whales killed in Cape Cod Bay in a single day during January 1700. By 1750, the North Atlantic right whale population was, for commercial purposes, depleted. Yankee whalers moved into the South Atlantic before the end of the 18th century. The population was so low by the mid-19th century that the famous Whitby whaler Rev. William Scoresby, son of the successful British whaler William Scoresby senior (1760–1829), claimed to have never seen a right whale (although he mainly hunted bowhead whales off eastern Greenland, outside the normal range of right whales).
Based on back calculations using the present population size and growth rate, the population may have numbered fewer than 100 individuals by 1935. As it became clear that hunting right whales was unsustainable, international protection for right whales came into effect, as the practice was banned globally in 1937. The ban was largely successful, although violations continued for several decades. Madeira took its last two right whales in 1967.
Threats For the period 1970 to October 2006, humans have been responsible for 48% of the 73 documented deaths of the North Atlantic right whale. A 2001 forecast showed a declining population trend in the late 1990s, and indicated a high probability that North Atlantic right whales would go extinct within 200 years if the then-existing anthropogenic mortality rate was not curtailed. The combined factors of small population size and low annual reproductive rate of right whales mean that a single death represents a significant increase in mortality rate. Conversely, significant reduction in the mortality rate can be obtained by preventing just a few deaths. It was calculated that preventing the deaths of just two females per year would enable the population to stabilize. The data suggests, therefore, that human sources of mortality may have a greater effect relative to population growth rates of North Atlantic right whales than for other whales. The principal factors known to be retarding growth and recovery of the population are ship strikes and entanglement with fishing gear.
Ship strikes
The single greatest danger to this species is injury sustained from ship strikes. Between 1970 and October 2006, 37% of all recorded North Atlantic right whale deaths were attributed to collisions. During the years 1999–2003, incidents of mortality and serious injury attributed to ship strikes averaged 1 per year. For the years 2004–2006, that number increased to 2.6. Additionally, it is possible that the official figures underestimate the actual ship-strike mortality rates, since whales struck in offshore areas may never be sighted due to low search effort.