Yet another species of right whale was proposed by Emanuel Swedenborg in the 18th century—the so-called Swedenborg whale. The description of this species was based on a collection of fossil bones unearthed at Norra Vånga, Sweden, in 1705 and believed to be those of giants. The bones were examined by Swedenborg, who realized they belong to a species of whale. The existence of this species has been debated, and further evidence for this species was discovered during the construction of a motorway in Strömstad, Sweden in 2009. To date, however, scientific consensus still considers Hunterius swedenborgii to be a North Atlantic right whale. According to a DNA analysis conducted, it was later confirmed that the fossil bones are actually from a bowhead whale.
The right whales were first classified in the genus Balaena in 1758 by Carl Linnaeus, who at the time considered all of the right whales (including the bowhead) as a single species. Through the 19th and 20th centuries, in fact, the family Balaenidae has been the subject of great taxonometric debate. Authorities have repeatedly recategorized the three populations of right whale plus the bowhead whale, as one, two, three or four species, either in a single genus or in two separate genera. In the early whaling days, they were all thought to be a single species, Balaena mysticetus. Eventually, it was recognized that bowheads and right whales were in fact different, and John Edward Gray proposed the genus Eubalaena for the right whale in 1864. Later, morphological factors such as differences in the skull shape of northern and southern right whales indicated at least two species of right whale – one in the Northern Hemisphere, the other in the Southern Ocean. As recently as 1998, Rice, in his comprehensive and otherwise authoritative classification listed just two species: Balaena glacialis (the right whales) and Balaena mysticetus (the bowheads).
"Yankee whalers" from the new American colonies replaced the Basques. Setting out from Nantucket, Massachusetts, and Long Island, New York, they took up to a hundred animals in good years. By 1750, the commercial hunt of the North Atlantic right whale was essentially over. The Yankee whalers moved into the South Atlantic before the end of the 18th century. The southernmost Brazilian whaling station was established in 1796, in Imbituba. Over the next hundred years, Yankee whaling spread into the Southern and Pacific Oceans, where the Americans were joined by fleets from several European nations. The beginning of the 20th century saw much greater industrialization of whaling, and the harvest grew rapidly. According to whalers' records, by 1937 there had been 38,000 takes in the South Atlantic, 39,000 in the South Pacific, 1,300 in the Indian Ocean, and 15,000 in the North Pacific. The incompleteness of these records means the actual take was somewhat higher.
Very little is known about the life span of right whales. One of the few well-documented cases is of a female North Atlantic right whale that was photographed with a baby in 1935, then photographed again in 1959, 1980, 1985, and 1992. Consistent callosity patterns ensured it was the same animal. She was last photographed in 1995 with a seemingly fatal head wound, presumably from a ship strike. By conservative estimates (e.g. she was a new mother who had just reached sexual maturity in 1935), she was nearly 70 years to more than 100 years of age, if not older. Research on the closely related bowhead whale exceeding 210 years suggests this lifespan is not uncommon and may even be exceeded.
As it became clear the stocks were nearly depleted, the world banned right whaling in 1937. The ban was largely successful, although violations continued for several decades. Madeira took its last two right whales in 1968. Japan took twenty-three Pacific right whales in the 1940s and more under scientific permit in the 1960s. Illegal whaling continued off the coast of Brazil for many years, and the Imbituba land station processed right whales until 1973. The Soviet Union illegally took at least 3,212 southern right whales during the 1950s and '60s, although it reported taking only four.
A second major cause of morbidity and mortality in the North Atlantic right whale is entanglement in plastic fishing gear. Right whales ingest plankton with wide-open mouths, risking entanglement in any rope or net fixed in the water column. Rope wraps around their upper jaws, flippers and tails. Some are able to escape, but others remain tangled. Whales can be successfully disentangled, if observed and aided. In July 1997, the U.S. NOAA introduced the Atlantic Large Whale Take Reduction Plan, which seeks to minimize whale entanglement in fishing gear and record large whale sightings in an attempt to estimate numbers and distribution.
The last major population review of southern right whales by the International Whaling Commission was in 1998. Researchers used data about adult female populations from three surveys (one in each of Argentina, South Africa and Australia) and extrapolated to include unsurveyed areas and estimated counts of males and calves (using available male:female and adult:calf ratios), giving an estimated 1997 population of 7,500 animals. More recent data from 2007 indicate those survey areas have shown evidence of strong recovery, with a population approaching twice that of a decade earlier. However, other breeding populations are still very small, and data are insufficient to determine whether they, too, are recovering.
In 2000, two studies of DNA samples from each of the whale populations concluded the northern and southern populations of right whale should be considered separate species. What some scientists found more surprising was the discovery that the North Pacific and North Atlantic populations are also distinct, and that the North Pacific species is more closely related to the southern right whale than to the North Atlantic right whale. The authors of one of these studies concluded that these species have not interbred for between 3 million and 12 million years.
The southern right whale, listed as "endangered" by CITES and "lower risk - conservation dependent" by the IUCN, is protected in the jurisdictional waters of all countries with known breeding populations (Argentina, Australia, Brazil, Chile, New Zealand, South Africa and Uruguay). In Brazil, a federal Environmental Protection Area encompassing some 1,560 km (600 sq mi) and 130 km (81 mi) of coastline in Santa Catarina State was established in 2000 to protect the species' main breeding grounds in Brazil and promote whale watching.
In 2001, Brownell et al. reevaluated the conservation status of the North Pacific right whale as a distinct species, and in 2002, the Scientific Committee of the International Whaling Commission (IWC) accepted Rosenbaum's findings, and recommended that the Eubalaena nomenclature be retained for this genus.
The US and Brazil added new protections for right whales in the 2000s to address the two primary hazards. While environmental campaigners were, as reported in 2001, pleased about the plan's positive effects, they attempted to force the US government to do more. In particular, they advocated 12 knots (22 km/h) speed limits for ships within 40 km (25 mi) of US ports in times of high right whale presence. Citing concerns about excessive trade disruption, it did not institute greater protections. The Defenders of Wildlife, the Humane Society of the United States and the Ocean Conservancy sued the NMFS in September 2005 for "failing to protect the critically endangered North Atlantic Right Whale, which the agency acknowledges is 'the rarest of all large whale species' and which federal agencies are required to protect by both the Marine Mammal Protection Act and the Endangered Species Act", demanding emergency protection measures.
Almost all of the 400 North Atlantic right whales live in the western North Atlantic Ocean. In northern spring, summer and autumn, they feed in areas off the Canadian and northeast U.S. coasts in a range stretching from New York to Newfoundland. Particularly popular feeding areas are the Bay of Fundy and Cape Cod Bay. In winter, they head south towards Georgia and Florida to give birth. There have been a smattering of sightings further east over the past few decades; several sightings were made close to Iceland in 2003. These are possibly the remains of a virtually extinct eastern Atlantic stock, but examination of old whalers' records suggests they are more likely to be strays. However, a few sightings have happened between Norway, Ireland, Spain, Portugal, the Canary Islands and Italy; at least the Norway individuals come from the Western stock.
On February 6, 2006, NOAA proposed its Strategy to Reduce Ship Strikes to North Atlantic Right Whales. The proposal, opposed by some shipping interests, limited ship speeds during calving season. The proposal was made official when on December 8, 2008, NOAA issued a press release that included the following:
In 2012, the U.S. Navy proposed to create a new undersea naval training range immediately adjacent to northern right whale calving grounds in shallow waters off the Florida/Georgia border. Legal challenges by leading environmental groups including the Natural Resources Defense Council were denied in federal court, allowing the Navy to proceed. These rulings were made despite the extremely low numbers (as low as 313 by some estimates) of right whales in existence at this time, and a very poor calving season.
The skin is generally black with occasional white blotches on the body, while some individuals have mottled patterns. Unlike other whales, a right whale has distinctive callosities (roughened patches of skin) on its head. The callosities appear white due to large colonies of cyamids (whale lice). Each individual has a unique callosities pattern. In 2016, a competitive effort resulted in the use of facial recognition software to derive a process to uniquely identify right whales with about 87% accuracy based on their callosities. The primary role of callosities has been considered to be protection against predators. Right whale declines might have also reduced barnacles.
In 2020, NOAA published its assessment and found that since the speed rule was adopted, the total number of documented deaths from vessel strike decreased but serious and non-serious injuries have increased. A report by the organization Oceana found that between 2017 and 2020, disobedience of the rule reached close to 90% in mandatory speed zones while in voluntary areas, disobedience neared 85%.