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|North Pacific right whale|
|Size compared to an average human|
|North Pacific right whale|
|Size compared to an average human|
The North Pacific right whale (Eubalaena japonica) is a very large, robust baleen whale species that is now extremely rare and endangered. The Northeast Pacific subpopulation, which summers in the southeastern Bering Sea and Gulf of Alaska, may have no more than 50 animals. A western subpopulation that summers in the Sea of Okhotsk between the Kuril Islands and Sakhalin Island appears to number in the low hundreds of animals. Prior to commercial whaling in the North Pacific (i.e. pre-1835) the populations in the North Pacific probably were over 20,000 animals. The taking of right whales in commercial whaling has been prohibited by one or more international treaties since 1935. Between 1962 and 1968, illegal Soviet whaling killed 529 right whales in the Bering Sea and Gulf of Alaska as well as 132 right whales in the Sea Okhotsk.
The International Union for the Conservation of Nature categorizes the species as "Endangered". It categorizes the Northeast Pacific subpopulation as "Critically Endangered". According to the Center for Biological Diversity, the North Pacific right whale is the most endangered whale on Earth.
E. japonica is a member of the family Balaenidae, and all species of this family are often lumped together in popular accounts as "right whales". This family consists of two genera: Balaena—with one species, the bowhead whale of the arctic (B. mysticetus), and Eubalaena—the "right whales", also often called "black right whales".
Despite a superficial resemblance to the much larger Eubalaena species, the pygmy right whale (Caperea marginata) of the Southern Hemisphere is not closely related, having been recently recognized as the sole living species of the family, Cetotheriidae.
Until recently, all right whales of the genus Eubalaena were considered a single species—E. glacialis. In 2000, genetic studies of right whales from the different ocean basins led scientists to conclude that the populations in the North Atlantic, North Pacific and Southern Hemisphere constitute three distinct species which they named: the North Atlantic right whale (Eubalaena glacialis), the North Pacific right whale (Eubalaena japonica) and the Southern right whale (Eubalaena australis). Further genetic analysis in 2005 using mitochondrial DNA and nuclear DNA has supported the conclusion that the three populations should be treated as separate species, and the separation has been adopted for management purposes by the U.S. National Marine Fisheries Service and the International Whaling Commission.
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 Balaenidae family serves to illustrate the current scientific consensus as to the relationships between the North Pacific right whale and the other members of its family.
|Family Balaenidae |
E. japonica is a very large, robust baleen whale. It very closely resembles the other right whale species—the North Atlantic right whale (E. glacialis) and the southern right whale (E. australis). Indeed, without knowing which ocean an individual came from, the physical similarities are so extensive that individuals can only be identified to species by genetic analysis. Relative to the other right whale species, E. japonica may be slightly larger. Like other baleen whales, female North Pacific right whales are larger than males. Also, North Pacific brindle-colored individuals are less common than they are among southern right whales.
E. japonica is easily distinguished in the wild from other whale species in the North Pacific. North Pacific Right whales are very large and can reach from 15 to 18.3 m (49 to 60 ft) in length as adults, larger than the North Atlantic Right Whale. Typical body mass is from 50,000–80,000 kg (110,000–180,000 lb). There is one record of a 19.8 m (65 ft) whale. They are much larger than gray or humpback whales. Right whales are also very stout, particularly when compared to the other large baleen whales such as blue and fin whales. For 10 North Pacific right whales taken in the 1960s, their girth in front of the flippers was 0.73 of the total length of the whale.
Right whales are also unique in that they all have callosities—roughened patches of epidermis covered with aggregations in clusters, of hundreds of small cyamids. As in other species of right whales, the callosities appear on its head immediately behind the blowholes, along the rostrum to the tip which often has a large callosity, referred to by whalers as the "bonnet".
The species most similar to the North Pacific right whale in the North Pacific/Bering Sea area is the closely related bowhead whale. Both species have huge heads that constitute up to one-third of the body length, highly arched mouths, very long, fine baleen, no dorsal fin, and great breadth. The seasonal ranges of the two species do not overlap. The bowhead whale is found at the edge of the pack ice in more Arctic waters in the Chuckchi Sea and Beaufort Sea, and occurs in the Bering Sea only during winter. The bowhead whale is not found in the North Pacific. Bowhead whales completely lack callosities, the easiest way to distinguish the two species.
Although more than 15,000 right whales were killed by whalers in the North Pacific, there are remarkably few detailed descriptions of these whales. Most of our information about the anatomy and morphology of E. japonica comes from 13 whales killed by Japanese whalers in the 1960s and 10 whales killed by Russian whalers in the 1950s. Basic information about right whale lengths and sex are also available from coastal whaling operations in the early part of the 20th century.
Before being decimated by pelagic whalers in the mid-19th century, right whales were common in the North Pacific. The number of right whales killed in Japanese shore-based net whaling or by Native American whalers in the Aleutians was almost certainly so small that it did not reduce the overall population size. Accordingly, one can consider 1835 as a good year to use as a baseline for the historic population. In the single decade of 1840–49, between 21,000–30,000 right whales may have been killed in the North Pacific, Sea of Okhotsk and Bering Sea. This suggests that right whales may have been as abundant as the gray whale in the North Pacific.
In 2010, National Marine Fisheries Service scientists estimated that the population of North Pacific right whales that summer in the southeastern Bering Sea was approximately 30 animals. More specifically, their mark-recapture photographic studies suggested a population of 31 whales (95% confidence level = 23–54); and their genotyping study suggested a population of 28 whales (95% confidence level = 24–42). The scientists estimated the population contains eight females (95% confidence level = 7–18) and 20 males (95% confidence level = 17–37). They concluded that "Although these estimates may relate to a Bering Sea subpopulation, other data suggest that the total eastern North Pacific population is unlikely to be much larger. In 2004, at least two calves were seen. In 1998 and 2004 an individual right whale was seen in the Gulf of Alaska near Kodiak Island and right whale calls were recorded from this area in 2000.
Prior estimates of current right whale population numbers in the eastern North Pacific were highly speculative. A comprehensive review of sighting data and population estimates in 2001 concluded that "none of the published estimates of abundance relating to North Pacific right whales can be regarded as reliable...[most] estimates appear to be little more than conjecture...[and] no quantitative data exist to confirm any of these estimates."
In a December 2006 status review of right whales, the U.S. National Marine Fisheries Service (NMFS) stated: "Recent sightings suggest that the abundance in the eastern North Pacific is indeed very small, perhaps in the tens of animals." The U.S. Marine Mammal Commission in its 2006 Annual Report stated that "the eastern population may now number no more than 50 individuals." A 2008 report by researchers "the extreme rarity of sightings in recent decades suggests that the population numbers in the tens."
A proposed oil and gas lease of North Aleutian Basin in the SE Bering Sea caused the Minerals Management Service (MMS) of the Department of the Interior to fund at an annual cost of about $1 million a cooperative series of annual surveys with the National Marine Fisheries Service and the North Pacific Research Board (NPRB), with a focus on located right whales and gathering further information about them.
An Argos PTT satellite transmitter was deployed in one and the whale was monitored for 58 days, a period in which it remained in a relatively small area within the middle shelf of the Eastern Bering Sea, just to the north of the North Aleutian Basin.
Pelagic whalers in the 19th century hunted large numbers of right whales along the coasts of Kamchatka and in the Sea of Okhotsk. The latter area is a large sea, ice covered most of the year, entirely in Russian waters. Due to Russian restrictions on access, little was known about whales in this sea. In the late 1980s and early 1990s, Japanese research vessels in the Sea of Okhotsk reported 28 sightings of right whales in the Sea of Okhotsk. From this sample, the Japanese scientists estimated a population of 900 right whales in the Sea of Okhotsk, albeit with low confidence intervals (90% CI = 400–2,100). After a gap of 14 years, Japanese researchers were able to resurvey this area in 2005 and apparently saw similar numbers of right whales in the same area. Other scientists have disputed the methodology used to extrapolate a total population size, and contend that the population may be less than half of that. Where these whales go in winter is very poorly understood.
Survey records from "JARPN" and "JARPN II" conducted from 1994 to 2007 by the Institute of Cetacean Research detected 28 groups of right whales totaling 40 individuals with 6 cow-calf pairs distributed mainly in offshore waters .
In summer 2009, a co-operative cetacean sighting survey was conducted in the Sea of Okhotsk by the Japanese National Research Institute of Far Seas Fisheries and the Russian (VNIRO) institute. During this survey, 17 groups of 29 right whales were recorded and photographed. Analysis of the photographs revealed no matches among the individuals resulting in a minimum record of 29 whales encountered during the survey.
Like right whales in other oceans, North Pacific right whales feed primarily on copepods, mainly the species Calanus marshallae. They also have been reported off Japan and in the Gulf of Alaska feeding on copepods of the genus Neocalanus with a small quantity of euphausiid larvae, Euphausia pacifica.
Like other right whale species, the North Pacific right whale feeds by skimming water continuously while swimming, in contrast to balaenopterid whales such as the blue and humpback whales which engulf prey in rapid lunges. Right whales do not have pleated throats. Instead they have very large heads and mouths that allows them to swim with their mouths open, the water with the copepods flowing in, then flowing sideways through the right whale's very long, very fine baleen trapping the copepods, and then out over their large lower lips.
It takes millions of the tiny copepods to provide the energy a right whale needs. Thus, right whales must find copepods at very high concentrations, greater than 3,000 per cubic meter to feed efficiently. National Marine Fisheries Service researchers mapped the southeast Bering Sea and the Gulf of Alaska for areas with sufficient productivity to support such concentrations and analyzed the roles of bathymetry and various gyres in concentrating copepods to such densities.
There have been very few, short visual observations of right whale behavior in the North Pacific. The mid-19th century whaling onslaught occurred before there was much scientific interest in whale behavior, and included no scientific observation. By the time scientific interest in this species developed, few whales remained and nowhere in the eastern North Pacific or Bering Sea could observers reliably find them. As of 2006, scientists had minimal success satellite tagging North Pacific right whales. Observations total probably less than 50 hours over the last 50 years. What little is known about North Pacific right whale behavior suggests that it is similar to the behavior of right whales in other oceans, except in its choice of wintering grounds. The individual which was observed during a whale-watching tour off the Kii Peninsula, Japan breached six times in a row. The same whale watching operator had a very close encounter with a right whale in 2011. This animal was very curious and active; it swam around the vessel for more than 2 hours, breaching, spyhopping, tail-slapping, and pec-slapping close to the boat. The ship had to cruise away from the whale because it kept following them.
Like the other Eubalaena species, North Pacific Right Whales are sometimes known to interact with other cetacean species. Several observations of North Pacific Right Whales to interact with groups or solitary individuals of Humpback Whales are recorded in both Eastern and Western North Pacific. A record of a pair of Gray Whales were seen showing signs of aggression towards a Right Whale and chasing it off California, 1998, while a sub-adult Right Whale was seen swimming in a group of critically endangered Western Gray Whales with social behaviors demonstrated in inshore water (Piltun Bay region) of Sakhalin's northeast coast in 2012.
There have been some noteworthy non-visual observations. NMFS biologists deployed various passive acoustic listening devices in the Bering Sea and Gulf of Alaska, recording at least 3,600 North Pacific right whale calls between 2000 and 2006. Nearly all of these calls came from the shallow shelf waters at approximately 70 m (230 ft) of the southeastern Bering Sea in what is now designated Critical Habitat for this species. 80% were frequency-modulated "up-calls" at an average 90–150 Hz and 0.7 second duration. "Down-up" calls constituted about 5% of the calls, and swept down for 10–20 Hz before becoming a typical "up-call". Other call types, e.g. downsweeps and constant-tonal "moans" constituted less than 10% of total calls. The calls were clumped temporally—apparently involving some level of social interaction, as has been found in the calls of right whales in other oceans. The calls came more at night than during the day.
The very small number of North Pacific right whale calls detected during the NMFS research—hundreds per year contrast with the vastly greater number (hundreds of thousands) of bowhead whale calls during migration in the western Arctic and blue whale calls off California—further reinforces the conclusion that the population size of North Pacific right whales in the Bering Sea is very small.
Before 1840, its range was extensive and had probably remained the same for at least hundreds of years. It ranged from the Sea of Okhotsk to the western coast of Canada. The seasonal movements and the densest concentrations of whales, then as now, are unknown.
To determine where the right whales were, an imaginative cooperation developed between whalers and one of the U.S.'s first oceanographers. In the 1840s, the principal mariners who ventured away from the main trade routes were whalers. The description of currents, winds, and tides in these remote regions was of great interest to the U.S. Navy. Accordingly, Naval Captain Matthew Fontaine Maury made a deal with whalers. If they provided him with their logbooks, from which he could extract wind and current information, he would in return prepare maps for them showing where whales were most concentrated. Between 1840 and 1843, Maury and his staff processed over 2,000 whaling logbooks and produced not only the famous Wind and Current Charts used by mariners for over a century, but also a series of Whale Charts. The most detailed showed by month and 5° of latitude and longitude: (a) the number of days on which whaling ships were in that sector; (b) the number of days on which they saw right whales; and (c) the number of days on which the saw sperm whales. In the North Pacific, these charts summarize more than 8,000 days on which the whalers encountered right whales and the searching effort by month and sector. The maps thus provide a crude measure of the relative abundance of right whales by geographic sector and month, controlled for the very non-random searching effort of the whalers.
North Pacific whalers hunted mainly in the summer, and that is reflected in the Maury Whale Charts. There were almost no winter sightings and very few south of 20°N. The densest concentrations occurred along both coasts of Kamchatka and in the Gulf of Alaska.
In 1935, Charles Townsend from the New York Zoological Society (now the Wildlife Conservation Society) reviewed 2,000 whaling logbooks and mapped the locations of whale taken by species. His Chart C shows catch locations around the world, including the location by month of most of the 2,118 right whales taken in the North Pacific between 1839 and 1909, using data copied from 249 logbooks. His charts do not adjust for the nonrandom distribution of whalers. Chart C shows three main concentrations of right whales—one in the Gulf of Alaska; one along Kamchatka and the Sea of Okhotsk; and another in the Sea of Japan.
Of particular interest are the questions of how many "stocks" of right whales exist in the North Pacific. Was there just a single population across the North Pacific? Was there an eastern population that summered in the Gulf of Alaska and a second population in the western North Pacific? Was the population in the Sea of Okhotsk a third population distinct from the whales found in the Pacific east of Kamchatka?
Recently, researchers reanalyzed this early whaling data, along with more recent, but much sparser, sighting data. They conclude that there are probably at least two stocks of right whales in the western and eastern North Pacific, but that it is still unclear whether the Okhotsk population is a separate stock.
The North Pacific right whale's distribution is more temperate than that of the more polar Bowhead whale, and there are no records of the two species inhabiting the same area at the same time. E. japonica's summer distribution extends north into the southeastern part of the Bering Sea. In summer, the Bowhead migrates north through the Bering Straits and is in the Chukchi Sea and Beaufort Sea. In winter, the ice-loving Bowhead moves south into the Bering Sea, but the right whales have migrated further south of the Aleutian Islands into the North Pacific.
Despite many aircraft and ship-based searches, as well as analysis of listening device records, only a few small areas report recent sightings in the eastern North Pacific. The southeastern Bering Sea produced the most, followed by the Gulf of Alaska, and then California. In 2000, 71 calls were recorded by a deep-water passive acoustic site at 53° N, 157° W. An additional 10 were recorded near Kodiak Island in the Gulf of Alaska at 57°N, 152°W, another whale which is thought to be a sub-adult animal was observed in Uganik Bay in December 2011, being the first modern record of the species on the western side of Kodiak Island. This was one of the few sightings that has occurred in inshore waters in the area. One right whale was seen in Pasagshak Bay on May, 2010. On August 10, 2004, a group of two were seen in the Bering Sea. Another sighting of 17 including two calves was noted in September, and one in the Gulf of Alaska. In 2005, 12 right whales were seen in October just north of Unimak Pass.
Review of more than 3,600 North Pacific right whale calls detected by passive listening devices between 2000–2006 strongly suggests that the whales migrate into the southeast Bering Sea in late spring and remain until late fall. The earliest were in late May and the latest in December. The peak calling period was July through October. Most were detected from shallow shelf sites within the designated Critical Habitat area. From October through December 2005, several calls were detected at the northwestern middle-shelf and the deeper shelf sites, suggesting that they may appear at different seasons and during migration.
There are very few reports of right whales in the western North Pacific. A remnant population of right whales persists in the Sea of Okhotsk at least in the summer, along with remnant populations of the eastern populations of Gray and Bowhead whales.
The distribution of these three species is quite different. In summer the Bowheads inhabit the northwestern corner of the Sea of Okhotsk around Academy Bay and Shantar Islands, probably also the northeast corner of the Sea. The gray whales stay close to Sakhalin Island, near massive new energy developments. In contrast, the right whales inhabit the southern Sea of Okhotsk nearer the Kuril Islands and northeast of Sakhalin Island. Some of recent sighting records are available.
Recent occurrences of right whales near the Kuril islands are largely unknown due to lack of observing efforts; however, recent sightings indicate that the areas adjacent to Paramushir Island and west of southern tip of Kamchatka Peninsula are seemingly one of the most populated locations for this species today.
Even though the eastern coast of the Kamchatka Peninsula is considered as a feeding ground for right whales, only a few records exist from the eastern side including sightings in 1978 and in 2009.
Right Whales were historically hunted in the Commander Islands heavily where only a handful of sightings are made in recent years, however, encounters with this species around the Commander Islands and off eastern Kamchatka seems to occur on a more regular basis compared to the last several decades. Whales have been observed very close to shore of less than 2 meters from the shore.
This area's remoteness makes observation very difficult and expensive. Based on survey records from "JARPN" and "JARPN II" conducted by Institute of Cetacean Research, the 40 right whales seen were distributed mainly in offshore waters from 1994 to 2007.
Large fractions of the other right whale species come close to shore in winter to mate or calve; no coastal or other wintering ground has been found for North Pacific right whales. Which factors cause right whales not to favor inshore waters is unknown. Off the west coast of the United States, Point Conception is a turning location in terms of sighting records in the 19th and 20th centuries, and this may contribute to support the once-abandoned idea; existence of historical breeding grounds in coastal waters including along North American continent. Ryukyu Islands had been suggested as a wintering ground for the western population, but little evidence supports this. According to Maury's chart, in winter, some concentrations could be seen at several areas such as the southern Sea of Japan, areas off Shanghai and the Zhoushan archipelago, Taiwan Strait, the northwestern Hawaiian Islands. (with smaller areas scattered among southern Korean and Japanese waters)There is a map forecasting wintering habitats for right whales in north Pacific according to environmental factors corresponding to that of north Atlantic species. Some whales were caught off Hainan Island and this area is possibly the southernmost location of known range for the western population. The whales are also known to occur around the northern Mariana Islands.
A breaching right whale was seen off the Shiretoko Peninsula in July 2013, making it the first record officially confirmed in southern Sea of Okhotsk since after scientific catches by Japan in the 1960s. An 18 m (59 ft) right whale was entangled off Kamogawa coast in May, but escaped while another 15-18 m (49-59 ft) carcass was seen floating off Cape Nozaki. A right whale of 10 m (32.8 ft) was sighted on 28 January 2014, making it the first record in the East China Sea in the 21st century. One whale about the same size entered the port of Ushibuka, Kumamoto on 28 March 2014.
In addition, possibly two different animals were seen off Bonin Islands on 12th and 25th March 2014. Later one was larger, and was curious towards whale-watching vessels (footage is available ). The whale was observed interacting with a Humpback whale. Izu and Bonin Islands are regions with highest confirmed sightings and strandings rates among tropical regions in the past century. In 1993, Yasuhiro Morita of Ogasawara Diving Center succeeded in encountering right whales on four different occasions near the Bonin Islands.
Constant appearances in both sides of Pacific were recorded until 1998 and all the southernmost records at 4 locations of almost same latitude were made in both sides around 1996-97; Amami Oshima, Bonin Islands, Hawaii, Cabo San Lucas. Last records off west coast were in 1998 off Cape San Martin and Monterey. Afterwards, any records ceased until 2014. In Bonin Islands and off Oregon and California, constant occurrences were confirmed in the 1990s. What factors caused sudden rise in sighting trends in the 2010s and disappearance in the 2000s in many of former range especially for mid-lower latitudes are unknown. Bonin Island is the only location where sighting interval of constance was confirmed and succeed underwater filming in modern times. Off Japan, sudden rises in number were confirmed in 2003, 2006, 2008, and in 2011 where exceptionally large number were recorded in 2011; at least 3 or more different sightings, 1 entanglement, 1 stranding of 18m animal.
Until recently, most researchers thought that right whales in the eastern North Pacific wintered off the west coast of North America, particularly along the coasts of Washington, Oregon and California. There have been few winter sightings in all these areas, particularly in California. A more detailed study argues that these single individuals were merely stragglers. Notwithstanding 7 days/week whale-watching operations in several parts of this range, there have been only 17 sightings between Baja and Washington state. The absence of calves from historic California stranding data suggests that this area was never an important calving or wintering ground.
No clear wintering or calving grounds have been detected in the western North Pacific. Most of recent sightings have occurred along the Japanese coast.
Historically, right whales may have wintered in the East China Sea from the Ryukyu Islands to south of China including Taiwan though there is little scientific evidence supporting this idea. Modern sightings in the East and South China Seas, or Yellow Sea are very rare, and the number of records is small. Only a few confirmed sightings in the area have occurred, including one from Amami Oshima in April 1997.
Some right whales still migrate south along Japan's coasts particularly the Pacific side of the archipelago, but what portion of the southward migration passes Japan is unknown. Right whales were formerly abundant off the coast of northeastern Japan where there have been a few sightings in recent years including observations from ICR research surveys (single animals confirmed off Kushiro, Hokkaido in September 2002 and off the Pacific coast of Honshu in April 2003). Local fishermen have regularly seen a few animals per year in the area (personal contact). There is one unconfirmed sighting off the Shiretoko Peninsula (a World Heritage Site) in 2008. A breaching right whale was observed during a sightseeing cruise in July 2013 making it the first confirmed sighting in the area for several decades and the first ever recorded in Hokkaido.
There are some locations along the Pacific side of Honshu where sightings are particularly more common; from south of Tokyo Bay to all around the Izu peninsula, from the Izu Islands to the Bonin Islands, the Kii Peninsula, Cape Muroto and adjacent waters. In the first area, there was one entanglement freed alive in April 2000 off Tateyama, and two strandings at Izu Oshima in 2002 and 2005.
Right whales may have wintered in the Bonin Islands, but few sightings in recent decades support this idea. The Ogasawara Whale-watching Association reported seeing 3 groups of 4 different right whales in the Bonin Islands in the 1990s (two animals from different groups were photographed and recorded on underwater video); A pair of possible right whales were seen migrating south outside the port of Aogashima in December 2007. Another group of 2 or 3 animals appeared just off Mikura island in March 2008. One animal was sighted very close to shore in Niijima, 2011 (later described). One whale stranded at Kumomi in 1977 - a local museum was built specially for displaying the animal's carcass.
Off the Kii peninsula, there was one sighting in June 1999, one mortal entanglement in April 2003, three records of two different animals in the spring-summer 2006 (both from many whale watching vessels). One of these whales was very active. A right whale escaped alive from a fishing net near Taiji Town in January 2009, a very close observation during whale watching tour (later described) in April, 2011. Off Cape Muroto, two entanglements (both escaped safely) were reported in February 1971 and February 2008. On occasion, right whales were confirmed by local fishermen off Tosa Bay(personal communication). Two adults stranded in the northern and southern Ibaraki Prefecture in 2003 and 2009.
Modern sightings in the Japan Sea are very seldom made. Some strandings were reported from the 1970s to late 2000s, but none of the possible sightings of right whales were published or confirmed. Whaling of right whales continued until 1978 in the Sea of Japan. A photo of a Right whale being hunted in 1922 in the Sea of Japan is available.
Unusually high numbers of right whales were recorded off Japan from February to mid-April 2011. One mature female of 18 m (59 ft) body length was stranded on the Shimoda coast on the southern Izu Peninsula. It had been previously sighted off Inatori, and interestingly, another animal was sighted very close to shore off Inatori again. A photo and a video are available. Another possible right whale was observed just outside a port in Manaduru in May (no photo was taken).
Off Kii Peninsula, in April 2011, the same whale-watching operator who had encountered two different right whales in 2006 had a very close encounter with a right whale. This whale was very curious and active; it swam around a vessel for more than 2 hours, displayed all the aerial actions several times (breaching, spyhopping, tail-slapping, pec-slapping) alongside the vessel, and the vessel had to cruise away from the whale because it kept following the vessel. Many professional whale photographers were on this tour, some of them were also on the board when this tour operator during the 2006 sightings.
Some whale watching or touring companies have encountered with several right whales or on several occasions such as several companies associated with "Ogasawara Whale Watching Association" (4 animals in the 1990s), "Nanki Marine Leisure Service"(3 different animals in 2006 and 2011), "Mikura Island Tourism Association"(2 whales in 2008), "Godzilla-rock cruise(Gojira-iwa kankou)" and its subsidiary, "Shiretoko Fox Cruise" since the 2000s(more than 3-4 times at least), "Heritage Expeditions"(at least 3 whales in the 2010s).
A young Right Whale was killed when it entangled itself in a net off Oita Prefecture in March, 2011. In fact, this was reported by a biologist who saw a right whale's meat being sold at a local market, later reported to a local aquarium.
A sailor on a yacht had a very close encounter with a cow-calf pair breaching off Miura Peninsula in the earlier 2000s. This sighting was later confirmed by a local marine biologist working at an aquarium.
Possibilities to encounter with North Pacific right whales during whale watching tours are extremely low, only a handful of operators around the world have had. One extraordinary case occurred in Japan. "Nanki Marine Leisure Service", a whale-watching operator working off Kumano-nada sea had 2 different encounters of different animals in 2006, and another one in 2011. For sighting in 2011, it could be one of most well-recorded observation ever in the world as some of aerial behaviors was observed for the first time such as keep following vessels over several hours. Several cameramen were on board both on 2006 and 2011, and Kenji Oda, a professional whale cameraman had two different encounters on 2006 and later.
So little is known about North Pacific right whales that any description of the threats they face necessarily involves some speculation. Much more is known about the threats faced by North Atlantic right whales, so a review of those threats is a good place to start.
When populations of wild animals get very small, the population becomes much more vulnerable to certain risks than larger populations. One of these risks is inbreeding depression.
A second risk of very small populations is their vulnerability to adverse events. In its 2006 Status Review, NMFS stated E. japonica's low reproductive rates, delayed sexual maturity, and reliance on high juvenile survivorship combined with its specialized feeding requirements of dense schools of copepods "make it extremely vulnerable to environmental variation and demographic stochasticity at such low numbers". For example, a localized food shortage for one or more years may reduce the population below a minimum size. As the NMFS Status Review notes: "Zooplankton abundance and density in the Bering Sea has been shown to be highly variable, affected by climate, weather, and ocean processes and in particular ice extent."
A third risk is mating. With so few whales in such a large area, simply finding a mate is difficult. Right whales generally travel alone or in very small groups. In other oceans, breeding females attract mates by calling. The success of this strategy depends upon having males within hearing range. As expanding shipping traffic increases the ocean's background noise, the audible range for such mating calls has decreased.
Oil and gas exploration and production in the right whale's range could threaten the species' survival as a result of oil spills, other pollution, ship collisions and noise. In its 2006 Status Review, NMFS notes that the development of the Russian oil fields off the Sakhalin Islands in the Sea of Okhotsk "is occurring within the habitat" of the western population of North Pacific right whales.
There have been recent oil spills in the Bering Sea. In 2005, the wreck of the M/V Selendang Ayu near Unalaska released approximately 321,000 US gallons (7,400 imp bbl) of fuel oil and 15,000 US gallons (350 imp bbl) of diesel into the Bering Sea.
The exploration phase of oil development is characterized by numerous ships engaged in seismic testing to map undersea geological formations. Testing involves blasts of noise which echo off the undersea rock formations. These explosions have been banned in the Beaufort Sea during the time of year that bowheads are present. In its 2006 Status Review, NMFS concludes: "In general, the impact of noise from shipping or industrial activities on the communication, behavior and distribution of right whales remains unknown."
On April 8, 2008, a NMFS review found that there had been no recent Outer Continental Shelf oil and gas activities in or adjacent to the areas designated as critical habitat for E. japonica. On the same day, the U.S. Minerals Management Service (MMS) published a notice of a proposed Oil and Gas Lease Sale 214 for 5,600,000 acres (23,000 km2) in the North Aleutian Basin. In January 2009, the MMS reported in a Scoping Report for the Environmental Impact Statement for the Lease Sale that "Many commentators expressed concern about impacts resulting from industrial activity and noise to the North Pacific right whales." More than half of the proposed Oil and Gas Lease Sale 214 in the Bering Sea is within the designated critical habitat of the North Pacific right whale.
On March 31, 2010, President Obama issued a memorandum for the Secretary of the Interior withdrawing Sale 214 from disposition by leasing through June 30, 2017, the Bristol Bay area of the North Aleutian Basin in Alaska. Right whales were not mentioned specifically in the reasons for this withdrawal.
The habitat of E. japonica is changing in ways that threaten its survival. Two environmental effects of particular concern are global warming and pollution.
The high densities of copepods that right whales require for normal feeding are the result of high phytoplankton productivity and currents which aggregate the copepods. Satellite studies of right whales show them traveling considerable distances to find these localized copepod concentrations.
Global warming can affect both copepod population levels and the oceanographic conditions which concentrate them. This ecological relationship has been studied intensively in the western North Atlantic.
Recently, scientists have begun to notice that the warming Arctic Ocean and land is resulting in changed distribution of species with the result of breaking down climate barriers that have prevented hybridization between closely related species. The most reported examples have been the three confirmed grizzly-polar bear hybrids. In 2010, a team led by National Marine Mammal Laboratory ecologist Brendan Kelly counted 34 possible hybridizations between distinct populations or species of Arctic marine mammals, many of which are endangered or threatened. These observed hybridizations included in 2009, a cross between a bowhead whale and a North Pacific right whale in the Bering Sea. Kelly stated that "The breedings between the North Pacific right whale, whose numbers have fallen below 200, and the more numerous bowhead whale, could push the former to extinction. (Over time, the hybrids would begin to outnumber the sparse right whales.)" Co-author Andrew Whitely wrote: "Breedings between these marine mammals near the North Pole are likely to result in fertile offspring, because many of these animals have the same number of chromosomes...[and] Over the short term the hybrid offspring from these Arctic animal matings will likely be strong and healthy, because unlike inbreeding, which magnifies deleterious genes, so-called outbreeding can mask these genes...But over time, as the hybrids mate randomly, those harmful genes will come out of hiding and make the offspring less fit and less capable of surviving."
In Sea of Okhotsk, habitat sharing with an endangered population of Bowhead Whales have been confirmed at north-west part of sea especially in Academy Bay region as well as critically endangered Western Gray Whales. Habitat sharing with Bowheads in these regions are known to occur historically as Right Whales had been recorded in these waters from days prior to commercial whalings or global warming. Extent of effect to both species by habitat sharing is unknown.
There is no record of entanglement in the Bering Sea and Gulf of Alaska. In the eastern Bering Sea gear is deployed in nearshore waters, areas "not associated and generally not overlapping with known North Pacific right whale distribution." Pot fisheries occur in offshore waters, but are often deployed in winter when right whales are not known to be present.
In the Sea of Okhotsk entanglement in fishing gear, like deep-water crab traps and Japanese pelagic driftnet gear for salmon may be a significant problem. Right whales have been found: alive but entangled in or wounded by crab net gear (2003 and 1996), dead from entanglement in unspecified gear (September 1995), dead from entanglement in Japanese drift net (October 1994), and alive with fishing gear wrapped on the tail flukes (August 1992). A young right whale was killed by being entangled in net in Oita Prefecture, Japan in March 2011. In fact, this was reported by a biologist who saw a right whale's meat being sold at a local market, later reported to a local aquarium.
Collisions with commercial ships are the greatest threat to North Atlantic right whales. Both summer feeding ranges and winter calving grounds are located in busy shipping channels. E. japonica does not frequent shipping channels. There is almost no published data that identifies or quantifies ship collisions or entanglement as substantial mortality factors for them.
In its 2006 Status Review, NMFS reviews the scientific studies on the effects of noise pollution on marine mammals and concludes: "In general, the impact of noise from shipping or industrial activities on the communication, behavior and distribution of right whales remains unknown."
Historic whaling is the reason North Pacific right whales are so endangered today. The two critical periods of whaling were 1839 to 1849 (pelagic whaling, 90% American ships) and 1963 to 1968 (illegal Soviet whaling). The illegal Soviet whaling in the 1960s killed 514 right whales in the Bering Sea and Gulf of Alaska to plus 136 right whales in the Sea Okhotsk and the Kuril Islands.
Although whaling was the principal threat to North Pacific right whales, there is no record of whalers targeting this species since the 1980s. Accordingly this threat appears minor at this time.
Trying to research and manage human interactions with whale populations that are spread out geographically in remote areas and hard to locate is expensive. With governments around the North Pacific facing reductions in budgets, funding for such efforts are becoming increasingly difficult to obtain. Most of the research on the right whales in the Bering Sea and Gulf of Alaska was funded as part of proposed leases for oil and gas exploration that recently have been deferred and that funding ended. The U.S. National Marine Fisheries Service reports "currently there is no funding at all for North Pacific right whale research despite the critically endangered nature of this population."
In Japan, the only system of collecting reports of large whales along the Japanese coast is the ICR Strandings Record - this applies only to stranded individuals, hence the limited knowledge about the biology of free-swimming right whales in Japan. There were more unpublished or unreported sightings of right whales confirmed by locals in recent years in which some important observations such as a cow-calf pairs observation close to shore are included (personal contact). For example, a sailor on a yacht had a very close encounter with a cow-calf pair breaching off Miura Peninsula in earlier 2000s. This sighting was later confirmed by a local marine biologist working at an aquarium.
The threshold problem for conserving this species is locating them. While the other right whale species appear predictably along their migration routes, there are no locations other than a small area in the southeastern Bering Sea where members of the eastern population can reliably be found. and 1997–2004. For example, during a month-long dedicated research cruises in August 2007 sighted no right whales.
There may be locations in the Sea of Okhotsk where right whales can reliably be found in summer. In the Sea of Okhotsk, the right whales are currently distributed far from shore in the southern part of the sea. The Sea is all Russian territorial waters, so Russian cooperation is required for any surveys. The remoteness of the location and the enormous demand for ships and aircraft associated with oil and gas exploration near Sakhalin Island, would make any ship or aerial surveys difficult and expensive.
In winter, the whales' distribution is particularly mysterious. There have been a few sightings close to shores in California and even Baja, particularly in the 1990s along locations like La Jolla, Point Sur, Big Sur coasts, Piedras Blancas, San Simeon, Point Montara, and in Santa Barbara Channel. They have been rare, of short duration and none since 1998. Largest numbers of whales sighted at one times in eastern Pacific outside of SE Bering Sea since after late 20th century were of 8 animals off Destruction Island in 1959, and 4 whales at the mouth of Yakutat Bay in March 1979.
One technology that holds promise for finding right whales is passive acoustic listening. Such devices record for hundreds of hours. The technology is able to detect submerged animals, independent of water clarity.
Another, expensive technology that can provide information about this species are satellite-monitored radio tags. These are non-lethal, and applied with a crossbow, can beam the whales' location, movements, dives and other information to researchers. The technique has been used successfully in the North Atlantic. The challenge is to bring the tag and the right whale together.
Acoustic detection and satellite tags can work together. In August 2004, NMFS listening devices in the southeastern Bering Sea detected right whale vocalizations. The researchers then deployed directional and ranging sonobuoys to locate the calling whales. This information allowed researchers to photograph and tag two right whales, and obtain genetic samples. Only one tag worked, and it failed after 40 days, just as the whale was expected to start its southern migration. During that period the whale moved throughout a large part of the shelf, including areas of the outer shelf where right whales have not been seen in decades.
The right whale's plight was recognized relatively early. Hunting them was prohibited in the first international whaling treaty, the International Convention for the Regulation of Whaling signed in 1931. The treaty came into effect in 1935. Although the United States, Canada and Mexico ratified the treaty, Japan and the Soviet Union did not, and thus were not bound by it. Attempts to bring the other major whaling nations under an international regime stalled until after World War II.
In 1946 the major whaling countries signed the International Convention for the Regulation of Whaling which established the International Whaling Commission (IWC) and took effect in 1949. The Commission's initial regulations barred whaling of right whales. Currently, the IWC classifies E. japonica a "Protection Stock" banning commercial whaling.
The International Whaling Commission sets maximum annual quotas for "commercial" whaling—zero in the case of right whales. The Convention authorized member countries to issue permits to take whales for scientific research. This exemption/loophole has recently become a heated, controversial subject as Japan has been testing the catch limits and the definition of scientific research, justifying such catches in the absence of a commercial quota. In 1955, the Soviet Union granted permits to kill 10 right whales, and in 1956 and 1958 the Japanese granted permits to kill 13 right whales. These 23 animals provided most published morphology and reproductive biology data. No further right whale permits have been issued by any country.
During the 1960s, the International Whaling Commission did not place observers on whaling ships. Whaling nations were expected to monitor their whalers. The Soviet Union abused this process, directing its whalers to capture thousands of protected blue whales, humpback whales and right whales around the world.
The North Pacific right whale is listed on Appendix I of the Convention on the Conservation of Migratory Species of Wild Animals (CMS) as this species has been categorized as being in danger of extinction throughout all or a significant proportion of their range and CMS Parties strive towards strictly protecting these animals, conserving or restoring the places where they live, mitigating obstacles to migration and controlling other factors that might endanger them.
The Whaling Convention Act of 1949 implements the ban on hunting right whales. The National Oceanic and Atmospheric Administration Fisheries Office for Law Enforcement (NOAA OLE) has jurisdiction.
Under the Endangered Species Act, E. japonica is listed as "endangered". Under the Marine Mammal Protection Act, all right whales, including E. japonica, were determined to be "depleted" in 1973 and remain so classified.
On 4 October 2000, the Center for Biological Diversity (CBD) petitioned NMFS to designate the southeast Bering Sea shelf from 55–60°N as critical habitat for E. japonica. On 20 February 2002, NMFS declined (67 FR 7660) at that time, arguing that available information was insufficient for such a finding. CBD challenged NMFS in court, and in June 2005, a federal judge directed the agency to make a designation. In 2006, NMFS complied, designating one in the Gulf of Alaska south of Kodiak Island and one in the southeast Bering Sea (71 FR 38277, 6 July 2006). Later, NMFS split the "northern right whale" into E. glacialis and E. japonica, and reissued its rule.
Critical habitats must contain one or more "primary constituent elements" (PCEs) that are essential to the conservation of the species. NMFS identified as PCEs:
NMFS simply used repeated right whale sightings in the same small area in spring and summer as a proxy for the presumed PCEs.
These areas support extensive and multi-species commercial fisheries for pollock, flatfish, cod, various crabs and other resources (but not salmon). NMFS ruled that these fisheries do not threaten PCE availability. NMFS also ruled that the zooplankton PCE was vulnerable to oil spills and discharges, which may require measures such as conditioning federal permits or authorizations with special operational constraints.
Once a critical habitat has been designated, federal agencies must consult with NMFS to ensure that any action they authorize, fund or carry out is unlikely to destroy or adversely modify it.
On January 23, 2013, NOAA issued a Draft Recovery Plan for the North Pacific Right Whale. In June 2013, NOAA issued the Final Recovery Plan for the North Pacific Right Whale. The Recovery Plan describes in considerable detail the current state of scientific knowledge of the species and the threats to its continued survival. The Plan also contains proposed conservation measures, which mainly consist of various research proposals including passive acoustic monitoring, satellite tagging, and review of historic whaling logbooks.
Previously, in December 1991, NMFS had approved a Final Recovery Plan for the "Northern right whale" (at the time NMFS considered the North Atlantic and North Pacific right whales to be the same species). The discussion in this 1991 Plan was almost entirely devoted to the North Atlantic Populations. After NMFS' decided to treat these two populations as separate species, NMFS revised this 1991 plan, limiting it to the North Atlantic right whale.
In Canada, some right whales had been caught in the early 20th century from whaling stations off northern Vancouver Island. There had been no sightings of right whales in Canadian waters since the large illegal Soviet kill in the 1960s with two exceptions of a pair confirmed off Queen Charlotte Islands at - in 1970 and two large whales seen off Strait of Juan de Fuca in 1983 though their species was unconfirmed. There were no officially-confirmed records until the sighting of a single right whale on June 9 and 13, 2013 south of Langara Island at the north end of the Queen Charlotte Islands (Haida Gwaii),in British Columbia (~ 54°N, 132°W)  followed by the second sighting of different individual at the mouth of the Strait of Juan de Fuca four months later.
In 2003, Fisheries and Oceans Canada issued a National Recovery Strategy for E. japonica in Pacific Canadian Waters. In 2012, Fisheries and Oceans Canada issued an analysis of critical habitat for North Pacific right whales, and blue,fin and sei whales in British Columbia. In 2013, Fisheries and Oceans Canada issued a Draft Partial Action Plan for Blue, Fin, Sei and North Pacific Right Whales (Balaenoptera musculus, B. physalus, B. borealis, and Eubalaena japonica) in Pacific Canadian Waters.
In Japan, hunting for right whales dates back at least to the 16th century, although stranded whales had been utilized for centuries before then. In 1675, Yoriharu Wada invented a new method of whaling, entangling the animals in nets before harpooning them. Initially the nets were made of straw, later replaced by the stronger hemp. A hunting group consisted of 15–20 Seko-bune or "beater" boats, 6 Ami-bune or netting boats and 4 Mosso-bune or tug boats, for a total of 30–35 boats with crews totaling about 400. In addition to right whales, they took gray whales and humpback whales.
Hunts took place in two regions: the south coast (Mie, Wakayama and Kochi prefectures) on the east coasts, and the waters north of the prefectures from Kyoto to Yamaguchi and to the west of Kyushu which hunted in the Sea of Japan. Off the south coast of Japan, hunting lasted from winter to spring. Catches in Kochi prefecture between 1800 and 1835 totaled 259 whales. Catches at Ine on the Sea of Japan during the periods 1700–1850 averaged less than 1 per year. Catches at Kawaijiri also on the Sea of Japan averaged 2 per year from 1699–1818.
A few Native American tribes hunted in the North Pacific. Their catches were much lower than the Japanese. The Inuit along the western and northwestern coasts of Alaska have hunted whales for centuries. They prefer the bowhead whale, and occasionally the gray whale. They hunted at or beyond the northern limits of the right whale's range.
Aleuts hunted E. japonica and Gray whales along the Aleutian Islands and the Alaska peninsula, using poisoned harpoons. The catch was not recorded, but is unlikely to be more than a few per year.
The Nootka, Makah, Quilleute and Auinault tribes of Vancouver Island and the coast of Washington were also skilled whalers of the gray and humpback whales. Right whales were rare in their catches.
The North Pacific was the furthest whaling ground from New England and Europe markets. During the open-boat whaling era, the mainly American ships hunted in the nearest ranges first. As the fleet grew, boats spread to the eastern North Atlantic and, by the 1770s, the South Atlantic. Following the lead of the British, American vessels first sailed the South Pacific in 1791, and by the end of the decade had reached the eastern North Pacific. By the 1820s, the whalers had started to use Lahaina, Hawaii as a base for hunting sperm whales.
In 1835, the French whaleship Gange ventured north of 50°N and became the first pelagic whaling ship to catch a North Pacific right whale. News of this find spread quickly. Whaleships north of 50° increased from 2 in 1839 to 108 in 1843 and to 292 in 1846. Approximately 90% of the whaleships were American, the remainder primarily French.
The focus of the North Pacific whaling fleet on right whales ended soon after 1848, when a whaler ventured through the Bering Straits and discovered unexploited populations of bowhead whales. Being more abundant, easier to capture, and yielding far more baleen, the majority of whalers rapidly switched to hunting bowheads. Since bowheads range further north than right whales, hunting pressure on right whales declined rapidly.
The estimated total catch in the fishery in the Gulf of Alaska, Bering Sea, North Pacific and Sea of Okhotsk was 26,500–37,000 right whales between 1839 and 1909. Eighty percent of this catch was concentrated in the single decade of 1840–49.
In the decade between 1850 and 1859, the catch dropped to 3,000–4,000 animals, one-sixth the previous level. Between 1860 and 1870, it dropped to 1,000 animals. By the end of the 19th century, pelagic whalers averaged less than 10 right whales per year.
In the late 19th century, steam propulsion and the explosive harpoon opened up new whaling opportunities. Species previously too swift to hunt commercially could now be caught—Blue and fin whales. Small coastal whaling operations opened in California, Oregon, and Washington, British Columbia, and in the Aleutian Islands and in southeast Alaska, and in the Kuril Islands in the west. Whalers hunted by day, towing their catch to shore for flensing, operating in a fairly small area around the whaling stations. Although they weren't the primary targets, a few right whales were recorded in catches from these stations. A close-up photo of a North Pacific right whale taken at the Kyuquot whaling station, British Columbia in 1918 can be seen here.
The later "factory ships" that processed carcasses while at sea further transformed pelagic whaling. Right whales continued to be taken, although uncommonly due to their rarity. Japan continued hunting right whales through the beginning of World War II. Afterward, General Douglas MacArthur, head of Allied occupation forces, encouraged the Japanese to resume whaling to feed their hungry population. Japan then joined the International Whaling Commission which barred the hunting of right whales. Except for 13 killed under "scientific permits", in accordance with IWC rules, Japanese whalers have honored this prohibition.
In the 1970s, four right whales were taken by Chinese (or actually by Japanese) and Korean whalers. There is no later record of targeting right whales. For the catches in the Yellow Sea, P Wang, the same researcher who reported the catch in December 1977 off Hai Yang Island in the Yellow Sea mentioned that it was possibly the same record as one in 1944 by Japanese whalers. Wang also reported a sighting of two whales in Hai Yang Island in January 1973 and another sighting of single animal in the same area in December 1977.
Historically, compliance with fisheries regulations regarding species caught and amount of the catch could be monitored when the fishing vessel returned to port, but with whaling factory ships, the whales were processed at sea, and the resulting products from all the baleen whales (whale oil, meat) were combined into a single commodity by the time the whaling ship reached port. As a consequence, a whaling operation that caught a protected right whale could cover up this infraction by combining the meat and oil with that from legal catches and misreporting it as a legal catch of a fin or several minke whales which would yield the same amount of product. Before DNA analysis of meat products became available very recently, such infractions could not be detected when the factory ship returned to port.
At the time, the only way to monitor compliance was by having whaling "inspectors" on the factory ships themselves to record the species and size of whales caught. When the International Whaling Commission (IWC) was established in 1946, monitoring of compliance with and enforcement of the IWC's regulations was the responsibility of each member nation with respect to its nationals' whaling operations. Each nation employed its own whaling inspectors at whaling stations and aboard whaling factory ships. Each member nation of the IWC was required to report to the IWC annually on compliance, describing the specifics of any infractions (e.g. number of illegal whales caught of which species), and what actions the member nation had taken regarding these infractions. The IWC itself has no legal authority to monitor whaling operations or impose sanctions on whaling operations for infractions. This policing of the whaling fleets by their own governments persisted until 1972 when the IWC established a system of international observers on whaling ships.
In the 1960s, Soviet whalers had no international observers on board, and no conservation groups following them at sea. By 1962, humpback, blue and fin whales were getting harder to find in the North Pacific, and the Soviet whalers, under great pressure from their own government to meet production targets, deliberately chose to hunt right whales, apparently killing every right whale they could over the next eight years, in the North Pacific and also the southern oceans. The Soviet government then filed fraudulent reports with the Bureau of International Whaling Statistics and the International Whaling Commission, admitting killing during this period only one right whale, by accident.
These Soviet infractions remained a state secret for four decades. In many instances, the Russian biologists who had been on the whaling ships were prohibited from examining the carcasses or taking any biological measurements of these whales. Nevertheless, several biologists kept their own records of what the whalers caught, then kept these records secret. After the collapse of the Soviet government, the new Russian government released at least part of the data on the true catch data.
In 2006, former Soviet whale biologist Nikolai Doroshenko published records of 372 right whales caught by the Soviet whaling fleets Vladivostok and Dalnij Vostok in the Bering Sea and eastern North Pacific between 1963 and 1968. He also documented an additional 126 right whales killed in the Sea of Okhotsk between 1963 and 1968 and another 10 in the Kuril Islands in 1971.
Doroshenko did not have information regarding catches by a third Soviet whaling fleet, the Sovetskaya Rossiya, operating in the Gulf of Alaska in 1962–1963 that caught 142 right whales that were additional to the 372 previously revealed. Of the whales killed by the Sovetskaya Rossiya fleet, 112 were killed in June 1963 in the central and northern Gulf of Alaska.
In 2012, newly discovered documents revealed that the total illegal catch was even larger. The current best estimate is that the Soviet whaling fleets caught 529 right whales from 1962 to 1968 in the eastern North Pacific, plus 152 more right whales in the Sea of Okhotsk in 1967 and 1968, for a total of 661 right whales. Catches were distributed in the Bering Sea (115), eastern Aleutian Islands (28), Gulf of Alaska (366), Sea of Okhotsk (132), and other areas (20). Detailed information on catches of 112 right whales taken in May/June 1963 shows a broad distribution in offshore waters of the Gulf of Alaska, consistent with 19th century historical whaling records. Other major areas in which right whales were caught include south of Kodiak Island, western Bristol Bay (southeastern Bering Sea), and the central Sea of Okhotsk off eastern Sakhalin Island. The catches primarily involved large mature animals, thus greatly inhibiting recovery of right whales in these regions.
It was also revealed that Japan was in fact 'helping' this destructive hunts in terms of neglecting and disregarding monitoring obligations, and there were agreements between Japan and Soviet to keep their illegal mass whaling activities in foreign/international protected waters in confidentiality.
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