Gray whale

The gray whale is traditionally placed as the only living species in its genus and family, Eschrichtius and Eschrichtiidae, but an extinct species was discovered and placed in the genus in 2017, the Akishima whale (E. akishimaensis). Some recent studies place gray whales as being outside the rorqual clade, but as the closest relatives to the rorquals. But other recent DNA analyses have suggested that certain rorquals of the family Balaenopteridae, such as the humpback whale, Megaptera novaeangliae, and fin whale, Balaenoptera physalus, are more closely related to the gray whale than they are to some other rorquals, such as the minke whales. The American Society of Mammalogists has followed this classification. John Edward Gray placed it in its own genus in 1865, naming it in honour of physician and zoologist Daniel Frederik Eschricht. The common name of the whale comes from its coloration. The subfossil remains of now extinct gray whales from the Atlantic coasts of England and Sweden were used by Gray to make the first scientific description of a species then surviving only in Pacific waters. The living Pacific species was described by Cope as Rhachianectes glaucus in 1869. Skeletal comparisons showed the Pacific species to be identical to the Atlantic remains in the 1930s, and Gray's naming has been generally accepted since. Although identity between the Atlantic and Pacific populations cannot be proven by anatomical data, its skeleton is distinctive and easy to distinguish from that of all other living whales. Many other names have been ascribed to the gray whale, including desert whale, devilfish, gray back, mussel digger and rip sack. The name Eschrichtius gibbosus is sometimes seen; this is dependent on the acceptance of a 1777 description by Erxleben. Taxonomic history A number of 18th century authors described the gray whale as Balaena gibbosa, the "whale with six bosses", apparently based on a brief note by : The gray whale was first described as a distinct species by based on a subfossil found in the brackish Baltic Sea, apparently a specimen from the now extinct north Atlantic population. Lilljeborg, however, identified it as "Balaenoptera robusta", a species of rorqual. realized that the rib and scapula of the specimen was different from those of any known rorquals, and therefore erected a new genus for it, Eschrichtius. were convinced that the bones described by Lilljeborg could not belong to a living species but that they were similar to fossils that Van Beneden had described from the harbour of Antwerp (most of his named species are now considered nomina dubia) and therefore named the gray whale Plesiocetus robustus, reducing Lilljeborg's and Gray's names to synonyms. Charles Melville Scammon produced one of the earliest descriptions of living Pacific gray whales, and notwithstanding that he was among the whalers who nearly drove them to extinction in the lagoons of the Baja California Peninsula, they were and still are associated with him and his description of the species. At this time, however, the extinct Atlantic population was considered a separate species (Eschrischtius robustus) from the living Pacific population (Rhachianectes glaucus). Things got increasingly confused as 19th century scientists introduced new species at an alarming rate (e.g. Eschrichtius pusillus, E. expansus, E. priscus, E. mysticetoides), often based on fragmentary specimens, and taxonomists started to use several generic and specific names interchangeably and not always correctly (e.g. Agalephus gobbosus, Balaenoptera robustus, Agalephus gibbosus). Things got even worse in the 1930s when it was finally realised that the extinct Atlantic population was the same species as the extant Pacific population, and the new combination Eschrichtius gibbosus was proposed. ==Description==

The gray whale has a dark slate-gray color and is covered by characteristic gray-white patterns, which are scars left by parasites that drop off in its cold feeding grounds. Individual whales are typically identified using photographs of their dorsal surface, matching the scars and patches associated with parasites that have either fallen off or are still attached. They have two blowholes on top of their head, which can create a distinctive heart-shaped blow at the surface in calm wind conditions. Gray whales measure from in length for newborns to for adults (females tend to be slightly larger than adult males). Newborns are a darker gray to black in color. A mature gray whale can reach , with a typical range of , making them the ninth largest sized species of cetacean. Notable features that distinguish the gray whale from other mysticetes include its baleen that is variously described as cream, off-white, or blond in color and is unusually short. The beard plate can reach in length. The gray whale's penis can reach at least in length. Its movement speed is slow, about , but it can reach speeds of up to when in danger. but there have been an observation of social behaviors between the two species on Sakhalin. Pacific groups The two populations of Pacific gray whales (east and west) are morphologically and phylogenically different. Other than DNA structures, differences in proportions of several body parts and body colors including skeletal features, and length ratios of flippers and baleen plates have been confirmed between Eastern and Western populations, and some claims that the original eastern and western groups could have been much more distinct than previously thought, enough to be counted as subspecies. Since the original Asian and Atlantic populations have become extinct, it is difficult to determine the unique features among whales in these stocks. However, there have been observations of some whales showing distinctive, blackish body colors in recent years. This corresponds with the DNA analysis of last recorded stranding in China. Differences were also observed between Korean and Chinese specimens. ==Populations==

North Pacific Two Pacific Ocean populations are known to exist: one population that is very low, whose migratory route is presumed to be between the Sea of Okhotsk and southern Korea, and a larger population numbering about 27,000 individuals in the eastern Pacific, traveling between the waters off northernmost Alaska and Baja California Sur. Mothers make this journey accompanied by their calves, usually hugging the shore in shallow kelp beds, and fight viciously to protect their young if they are attacked, earning gray whales the moniker "devil fish." Even a very small number of additional annual female deaths will cause the subpopulation to decline. However, as of 2018, evidence has indicated that the western population is markedly increasing in number, especially off Sakhalin Island. Following this, the IUCN downlisted the population's conservation status from critically endangered to endangered. North Atlantic The gray whale became extinct in the North Atlantic in the 18th century. They had been seasonal migrants to coastal waters of both sides of Atlantic, including the Baltic Sea, the Wadden Sea, the Gulf of St. Lawrence, the Bay of Fundy, Pamlico Sound and possibly Hudson Bay. Radiocarbon dating of subfossil or fossil European (Belgium, the Netherlands, Sweden, the United Kingdom) coastal remains confirms this, with whaling the possible cause for the population's extinction. A 2018 study utilizing ancient DNA barcoding and collagen peptide matrix fingerprinting confirmed that Roman era whale bones east of the Strait of Gibraltar were gray whales (and North Atlantic right whales), confirming that gray whales once ranged into the Mediterranean. Similarly, radiocarbon dating of American east coastal subfossil remains confirm that gray whales existed there at least through the 17th century. This population ranged at least from Southampton, New York, to Jupiter Island, Florida, the latest from 1675. A. B. Van Deinse points out that the "scrag whale", described by P. Dudley in 1725 as one of the species hunted by the early New England whalers, was almost certainly the gray whale. Since the 2010s, there have been occasional sightings of gray whales in the Atlantic Ocean and in the Mediterranean Sea, including one off the coast of Israel and one off the coast of Namibia. These were presumably migrants from the North Pacific population through the Arctic Ocean. That study suggested that over the past 100,000 years there have been several migrations of gray whales between the Pacific and Atlantic, with the most recent large scale migration of this sort occurring about 5,000 years ago. followed by sightings in Algeria and Italy. Pre-whaling abundance Researchers used a genetic approach to estimate pre-whaling abundance based on samples from 42 gray whales, and reported DNA variability at 10 genetic loci consistent with a population size of 76,000–118,000 individuals, three to five times larger than the average census size as measured through 2007. The National Oceanic and Atmospheric Administration has collected surveys of gray whale population since at least the 1960s. They state that "the most recent population estimate [from 2007] was approximately 19,000 whales, with a high probability (88%) that the population is at 'optimum sustainable population' size, as defined by the Marine Mammal Protection Act." They speculate that the ocean ecosystem has likely changed since the pre-whaling era, making a return to pre-whaling numbers infeasible. Factors limiting or threatening current population levels include ship strikes, entanglement in fishing gear, and changes in sea-ice coverage associated with climate change. Integration and recolonization Several whales seen off Sakhalin and on Kamchatka Peninsula have been confirmed to migrate towards eastern side of Pacific and join the larger eastern population. In January 2011, a gray whale that had been tagged in the western population was tracked as far east as the eastern population range off the coast of British Columbia. Recent findings from either stranded or entangled specimens indicate that the original western population have become functionally extinct, and possibly all the whales that have appeared on Japanese and Chinese coasts in modern times are vagrants or re-colonizers from the eastern population. Recent increases in sightings are confirmed in Arctic areas of the historic range for Atlantic stocks, most notably on several locations in the Laptev Sea including the New Siberian Islands in the East Siberian Sea, and around the marine mammal sanctuary of the Franz Josef Land, indicating possible earlier pioneers of re-colonizations. These whales were darker in body color than those whales seen in Sea of Okhotsk. It has been speculated that this whale crossed from the Pacific to the Atlantic via the Northwest Passage, since an alternative route around Cape Horn would not be contiguous to the whale's established territory. There has been gradual melting and recession of Arctic sea ice with extreme loss in 2007 rendering the Northwest Passage "fully navigable". In March 2021, a gray whale was sighted near Rabat, the capital of Morocco. In December 2023, a gray whale was sighted off Sunny Isles Beach, Florida. Genetic analysis of fossil and prefossil gray whale remains in the Atlantic Ocean suggests several waves of dispersal from the Pacific to the Atlantic related to successive periods of climactic warming – during the Pleistocene before the last glacial period and the early Holocene immediately following the opening of the Bering Strait. This information and the recent sightings of Pacific gray whales in the Atlantic, suggest that another range expansion to the Atlantic may be starting. ==Life history==

. Reproduction s of gray whale (1874 illustration) and outline of head showing spouthole Breeding behavior is complex and often involves three or more animals. Both male and female whales reach puberty between the ages of 6 and 12 with an average of eight to nine years. During the breeding season, it is common for females to have several mates. This single ovulation event is believed to coincide with the species' annual migration patterns, when births can occur in warmer waters. In the latter half of the pregnancy, the fetus experiences a rapid growth in length and mass. Similar to the narrow breeding season, most calves are born within a six-week time period in mid January. Feeding , California The whale feeds mainly on benthic crustaceans (such as amphipods and ghost shrimp), which it eats by turning on its side and scooping up sediments from the sea floor. This unique feeding selection makes gray whales one of the most strongly reliant on coastal waters among baleen whales. It is classified as a baleen whale and has baleen, or whalebone, which acts like a sieve, to capture small sea animals, including amphipods taken in along with sand, water and other material. Off Vancouver Island, gray whales commonly feed on shrimp-like mysids. When mysids are abundant gray whales are present in fairly large numbers. Despite mysids being a prey of choice, gray whales are opportunistic feeders and can easily switch from feeding planktonically to benthically. When gray whales feed planktonically, they roll onto their right side while their fluke remains above the surface, or they apply the skimming method seen in other baleen whales (skimming the surface with their mouth open). This skimming behavior mainly seems to be used when gray whales are feeding on crab larvae. Other prey items include polychaete worms, herring eggs, various forms of larvae, and small fish. Gray whales seem to favor feeding planktonically in their feeding grounds, but benthically along their migration route in shallower water. Mostly, the animal feeds in the northern waters during the summer; and opportunistically feeds during its migration, depending primarily on its extensive fat reserves. Another reason for this opportunistic feeding may be the result of population increases, resulting in the whales taking advantage of whatever prey is available, due to increased competition. Feeding areas during migration seem to include the Gulf of California, Monterey Bay and Baja California Sur. Calf gray whales drink of their mothers' 53% fat milk per day. The main feeding habitat of the western Pacific subpopulation is the shallow ( depth) shelf off northeastern Sakhalin Island, particularly off the southern portion of Piltun Lagoon, where the main prey species appear to be amphipods and isopods. Some gray whales have also been seen off western Kamchatka, but to date all whales photographed there are also known from the Piltun area. Range expansions due to recoveries and re-colonization in the future is likely to happen and the predicted range covers wider than that of today. The gray whale undergoes the longest migration of any mammal. Eastern Pacific population Each October, as the northern ice pushes southward, small groups of eastern gray whales in the eastern Pacific start a two- to three-month, trip south. Beginning in the Bering and Chukchi seas and ending in the warm-water lagoons of Mexico's Baja California Peninsula and the southern Gulf of California, they travel along the west coast of Canada, the United States and Mexico. Traveling night and day, the gray whale averages approximately per day at an average speed of . This round trip of is believed to be the longest annual migration of any mammal. By mid-December to early January, the majority are usually found between Monterey and San Diego such as at Morro bay, often visible from shore. Gray whales once ranged into Sea of Cortez and Pacific coasts of continental Mexico south to the Islas Marías, Bahía de Banderas, and Nayarit/Jalisco, and there were two modern calving grounds in Sonora (Tojahui or Yavaros) and Sinaloa (Bahia Santa Maria, Bahia Navachiste, La Reforma, Bahia Altata) until being abandoned in the 1980s. These first whales to arrive are usually pregnant mothers looking for the protection of the lagoons to bear their calves, along with single females seeking mates. By mid-February to mid-March, the bulk of the population has arrived in the lagoons, filling them with nursing, calving and mating gray whales. Throughout February and March, the first to leave the lagoons are males and females without new calves. Pregnant females and nursing mothers with their newborns are the last to depart, leaving only when their calves are ready for the journey, which is usually from late March to mid-April. Often, a few mothers linger with their young calves well into May. Whale watching in Baja's lagoons is particularly popular because the whales often come close enough to boats for tourists to pet them. By late March or early April, the returning animals can be seen from Puget Sound to Canada. Resident groups within residential range. A population of about 200 gray whales stay along the eastern Pacific coast from Canada to California throughout the summer, not making the farther trip to Alaskan waters. This summer resident group is known as the Pacific Coast feeding group. Any historical or current presence of similar groups of residents among the western population is currently unknown, however, whalers' logbooks and scientific observations indicate that possible year-round occurrences in Chinese waters and Yellow and Bohai basins were likely to be summering grounds. two single individuals stayed in Ise Bay for almost two months in the 1980s and in 2012, the first confirmed living individuals in Japanese EEZ in the Sea of Japan and the first of living cow-calf pairs since the end of whaling stayed for about three weeks on the coastline of Teradomari in 2014. One of the pair returned to the same coasts at the same time of the year in 2015 again. . The current western gray whale population summers in the Sea of Okhotsk, mainly off Piltun Bay region at the northeastern coast of Sakhalin Island (Russian Federation). There are also occasional sightings off the eastern coast of Kamchatka (Russian Federation) and in other coastal waters of the northern Okhotsk Sea. Gray whale had not been observed on Commander Islands until 2016. The northwestern pacific population consists of approximately 300 individuals, based on photo identification collected off of Sakhalin Island and Kamchatka. Any records of the species had not been confirmed since after 1921 on Kyushu. in Ine Bay in the Gulf of Wakasa, and in Tsushima. Gray whales, along with other species such as right whales and Baird's beaked whales, were common features off the north eastern coast of Hokkaido near Teshio, Ishikari Bay near Otaru, the Shakotan Peninsula, and islands in the La Pérouse Strait such as Rebun Island and Rishiri Island. These areas may also have included feeding grounds. along the Tottori Sand Dunes, in the Suou-nada Sea, and Ōmura Bay. The historical calving grounds were unknown but might have been along southern Chinese coasts from Zhejiang and Fujian Province to Guangdong, especially south of Hailing Island and captures), and any presence in other areas outside of the known ranges off Babuyan Islands in Philippines and coastal Vietnamese waters in Gulf of Tonkin are unknown. There is only one confirmed record of accidentally killing of the species in Vietnam, at Ngoc Vung Island off Ha Long Bay in 1994 and the skeleton is on exhibition at the Quang Ninh Provincial Historical Museum. Gray whales are known to occur in Taiwan Strait even in recent years. It is also unknown whether any winter breeding grounds ever existed beyond Chinese coasts. For example, it is not known if the whales visited the southern coasts of the Korean Peninsula, adjacent to the Island of Jeju, Haiyang Island, the Gulf of Shanghai, or the Zhoushan Archipelago. There is no evidence of historical presence in Japan south of Ōsumi Peninsula; only one skeleton has been discovered in Miyazaki Prefecture. once considered the Seto Inland Sea to be a historical breeding ground, but only a handful of capture records support this idea, although migrations into the sea have been confirmed. Recent studies using genetics and acoustics, suggest that there are several wintering sites for western gray whales such as Mexico and the East China sea. However, their wintering ground habits in the western North Pacific are still poorly understood and additional research is needed. Recent migration in Asian waters , Izu Islands in March, 2017. Even though South Korea put the most effort into conservation of the species among the Asian nations, there are no confirmed sightings along the Korean Peninsula or even in the Sea of Japan in recent years. The last confirmed record in Korean waters was the sighting of a pair off Bangeojin, Ulsan in 1977. Prior to this, the last was of catches of 5 animals off Ulsan in 1966. There had been 24 records along Chinese coasts including sighting, stranding, intended hunts, and bycatches since 1933. The last report of occurrence of the species in Chinese waters was of a stranded semi adult female in the Bohai Sea in 1996, and the only record in Chinese waters in the 21st century was of a fully-grown female being killed by entanglement in Pingtan, China in November, 2007. In 2011, presences of gray whales were acoustically detected among pelagic waters in East China Sea between Chinese and Japanese waters. Since the mid-1990s, almost all the confirmed records of living animals in Asian waters were from Japanese coasts. There have been eight to fifteen sightings and stray records including unconfirmed sightings and re-sightings of the same individual, and one later killed by net-entanglement. The most notable of these observations are listed below: • The feeding activities of a group of two or three whales that stayed around Izu Ōshima in 1994 for almost a month were recorded underwater • A pair of thin juveniles were sighted off Kuroshio, Kōchi, a renowned town for whale-watching tourism of resident and sub-resident populations of Bryde's whales, in 1997. This sighting was unusual because of the location on mid-latitude in summer time. • Another pair of sub-adults were confirmed swimming near the mouth of Otani River in Suruga Bay in May, 2003. was later confirmed to be the same individual as the small whale observed off Tahara near Cape Irago in 2010, making it the first confirmed constant migration out of Russian waters. The juvenile observed off Owase in Kumanonada Sea in 2009 might or might not be the same individual. The Ise and Mikawa Bay region is the only location along Japanese coasts that has several records since the 1980s (a mortal entanglement in 1968, above mentioned short-stay in 1982, self-freeing entanglement in 2005), Two individuals, measuring ten and five metres respectively, stayed near the mouth of Shinano River for three weeks. • A juvenile or possibly or not with another larger individual remained in Japanese waters between January or March and May 2015. It was first confirmed occurrences of the species on remote, oceanic islands in Japan. One or more visited waters firstly on Kōzu-shima and Nii-Jima for weeks then adjacent to Miho no Matsubara and behind the Tokai University campus for several weeks. Possibly the same individual was seen off Futo as well. This later was identified as the same individual previously recorded on Sakhalin in 2014, the first re-recording one individual at different Asian locations. • A young whale was observed by land-based fishermen at Cape Irago in March, 2015. • One of the above pair appeared in 2015 off southeastern Japan and then reappeared off Tateyama in January, 2016. The identity of this whale was confirmed by Nana Takanawa who photographed the same whale on Niijima in 2015. Likely the same individual was sighted off Futo The whale then stayed next to a pier on Miyake-jima and later at Habushi beach on Niijima, the same beach the same individual stayed near on the previous year. • One whale of was beached nearby Wadaura on March 4, 2016. Investigations on the corpse indicate that this was likely a different individual from the above animal. • A carcass of young female was firstly reported floating along Atami on 4 April then was washed ashore on Ito on the 6th. • As of April 20, 2017, one or more whale(s) have been staying within Tokyo Bay since February although at one point another whale if or if not the same individual sighted off Hayama, Kanagawa. It is unclear the exact number of whales included in these sightings; two whales reported by fishermen and Japanese coastal guard reported three whales on 20th or 21st. ==Whaling==

North Pacific 's 1874 illustration of a gray whale Eastern population Humans and orcas are the adult gray whale's only predators, although orcas are the more prominent predator. The carcass of a long adult female Gray whale, believed to have been eaten by an orca, was once found. Aboriginal hunters, including those on Vancouver Island and the Makah in Washington, have hunted gray whales. Commercial whaling of the species by Europeans in the North Pacific began in the winter of 1845–46, when two United States ships, the Hibernia and the United States, under Captains Smith and Stevens, caught 32 in Magdalena Bay. More ships followed in the two following winters, after which gray whaling in the bay was nearly abandoned because "of the inferior quality and low price of the dark-colored gray whale oil, the low quality and quantity of whalebone from the gray, and the dangers of lagoon whaling." Gray whaling in Magdalena Bay was revived in the winter of 1855–56 by several vessels, mainly from San Francisco, including the ship Leonore, under Captain Charles Melville Scammon. This was the first of 11 winters from 1855 through 1865 known as the "bonanza period", during which gray whaling along the coast of Baja California reached its peak. Not only were the whales taken in Magdalena Bay, but also by ships anchored along the coast from San Diego south to Cabo San Lucas and from whaling stations from Crescent City in northern California south to San Ignacio Lagoon. During the same period, vessels targeting right and bowhead whales in the Gulf of Alaska, Sea of Okhotsk, and the Western Arctic would take the odd gray whale if neither of the more desirable two species were in sight. In the winter of 1859–60, Scammon, again in the bark Ocean Bird, along with several other vessels, entered San Ignacio Lagoon to the south where he discovered the last breeding lagoon. Within only a couple of seasons, the lagoon was nearly devoid of whales. A whaling station in Richmond, California, caught 311 gray whales for "scientific purposes" between 1964 and 1969. From 1961 to 1972, the Soviet Union caught 138 gray whales (they originally reported not having taken any). The only other significant catch was made in two seasons by the steam-schooner California off Malibu, California. In the winters of 1934–35 and 1935–36, the California anchored off Point Dume in Paradise Cove, processing gray whales. In 1936, gray whales became protected in the United States. Western population The Japanese began to catch gray whales beginning in the 1570s. At Kawajiri, Nagato, 169 gray whales were caught between 1698 and 1889. At Tsuro, Shikoku, 201 were taken between 1849 and 1896. Several hundred more were probably caught by American and European whalemen in the Sea of Okhotsk from the 1840s to the early 20th century. Whalemen caught 44 with nets in Japan during the 1890s. The real damage was done between 1911 and 1933, when Japanese whalemen killed 1,449 after Japanese companies established several whaling stations on Korean Peninsula and on Chinese coast such as near the Daya bay and on Hainan Island. By 1934, the western gray whale was near extinction. From 1891 to 1966, an estimated 1,800–2,000 gray whales were caught, with peak catches of between 100 and 200 annually occurring in the 1910s. It is thought to have been hunted to extinction in the eastern North Atlantic in the 12th to 14th centuries with it being the second most common whale taxa found at archaeological sites in Europe up to the medieval period. Formations of commercial whaling among the Mediterranean basin(s) have been considered to be feasible as well. ==Conservation==

. Gray whales have been granted protection from commercial hunting by the International Whaling Commission (IWC) since 1949, and are no longer hunted on a large scale. Limited hunting of gray whales has continued since that time, however, primarily in the Chukotka region of northeastern Russia, where large numbers of gray whales spend the summer months. This hunt has been allowed under an "aboriginal/subsistence whaling" exception to the commercial-hunting ban. Anti-whaling groups have protested the hunt, saying the meat from the whales is not for traditional native consumption, but is used instead to feed animals in government-run fur farms; they cite annual catch numbers that rose dramatically during the 1940s, at the time when state-run fur farms were being established in the region. Although the Soviet government denied these charges as recently as 1987, in recent years the Russian government has acknowledged the practice. The Russian IWC delegation has said that the hunt is justified under the aboriginal/subsistence exemption, since the fur farms provide a necessary economic base for the region's native population. Currently, the annual quota for the gray whale catch in the region is 140 per year. Pursuant to an agreement between the United States and Russia, the Makah tribe of Washington claimed four whales from the IWC quota established at the 1997 meeting. With the exception of a single gray whale killed in 1999, the Makah people have been prevented from hunting by a series of legal challenges, culminating in a United States federal appeals court decision in December 2002 that required the National Marine Fisheries Service to prepare an Environmental Impact Statement. On September 8, 2007, five members of the Makah tribe shot a gray whale using high-powered rifles in spite of the decision. The whale died within 12 hours, sinking while heading out to sea. spots a gray whale in the Cordell Bank National Marine Sanctuary during a field trip for the Every Kid in a Park program in 2016. As of 2018, the IUCN regards the gray whale as being of least concern from a conservation perspective. However, the specific subpopulation in the northwest Pacific is regarded as being critically endangered. was registered as the 126th national monument in 1962, although illegal hunts have taken place thereafter, this plan has not been undertaken. ==Threats==

According to the Government of Canada's Management Plan for gray whales, threats to the eastern North Pacific population of gray whales include: increased human activities in their breeding lagoons in Mexico, climate change, acute noise, toxic spills, aboriginal whaling, entanglement with fishing gear, boat collisions, and possible impacts from fossil fuel exploration and extraction. Western gray whales are facing large-scale offshore oil and gas development programs near their summer feeding grounds, as well as fatal net entrapments off Japan during migration, which pose significant threats to the future survival of the population. Meats for sale were also discovered in Japanese markets as well. 2019 has had a record number of gray whale strandings and deaths, with 122 strandings in United States waters and 214 in Canadian waters. The cause of death in some specimens appears to be related to poor nutritional condition. It is hypothesized that some of these strandings are related to changes in prey abundance or quality in the Arctic feeding grounds, resulting in poor feeding. Some scientists suggest that the lack of sea ice has been preventing the fertilization of amphipods, a main source of food for gray whales, so that they have been hunting krill instead, which is far less nutritious. More research needs to be conducted to understand this issue. A recent study provides some evidence that solar activity is correlated to gray whale strandings. When there was a high prevalence of sunspots, gray whales were five times more likely to strand. A possible explanation for this phenomenon is that solar storms release a large amount of electromagnetic radiation, which disrupts Earth's magnetic field and/or the whale's ability to analyze it. This may apply to the other species of cetaceans, such as sperm whales. However, there is not enough evidence to suggest that whales navigate through the use of magnetoreception (an organism's ability to sense a magnetic field). Orcas are "a prime predator of gray whale calves." Typically three to four orcas ram a calf from beneath in order to separate it from its mother, who defends it. Humpback whales have been observed defending gray whale calves from orcas. It is roughly estimated that 33% of the gray whales born in a given year might be killed by predation. ==Captivity==

Because of their size and need to migrate, gray whales have rarely been held in captivity, and then only for brief periods of time. The first captive gray whale, who was captured in Scammon's Lagoon, Baja California in 1965, was named Gigi and died two months later from an infection. The second gray whale, who was captured in 1972 from the same lagoon, was named Gigi II and was released a year later after becoming too large for the facilities. The third gray whale, J.J., first beached herself in 1997 in Marina del Rey, California where she was rushed to SeaWorld San Diego. After 14 months, she was released because she also grew too large to be cared for in the existing facilities. At and when she was released, J.J. was the largest marine mammal ever to be kept in captivity. ==See also==