View source for Gray whale

{{Short description|Baleen whale that is the sole living member of Eschrichtius}}
{{Speciesbox
| name = Gray whale<ref name=msw3>{{MSW3 Cetacea | id = 14300030}}</ref>
| fossil_range = {{fossilrange|Late Pleistocene|Recent|ref=<ref>{{cite journal |last=Boessenecker|first=Robert|year=2007|title=New records of fossil fur seals and walruses (Carnivora: Pinnipedia) from the late Neogene of Northern California|volume=27|page=50A |journal=Journal of Vertebrate Paleontology}}</ref><ref name=Alter/>}}
| image = Ballena gris adulta con su ballenato.jpg
| image_caption = Gray whale [[Cetacean surfacing behaviour#Spyhopping|spy-hopping]] next to calf
| image2 = Gray whale size.svg
| image2_caption = Size compared to an average human
| image2_alt = Illustration showing whale next to human diver. The whale is many times larger than the human
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Cooke, J.G. |date=2018 |title=''Eschrichtius robustus'' |volume=2018 |article-number=e.T8097A50353881 |doi=10.2305/IUCN.UK.2018-2.RLTS.T8097A50353881.en |access-date=19 November 2021}}</ref>
 | status2 = CITES_A1 
 | status2_system = CITES 
 | status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref>
| genus = Eschrichtius
| species = robustus
| authority = [[Wilhelm Lilljeborg|Lilljeborg]], 1861
| range_map = Cypron-Range Eschrichtius robustus.svg
| range_map_caption = Gray whale range
| synonyms =
*''Balaena gibbosa'' <small>Erxleben, 1777</small>
*''Agaphelus glaucus'' <small>Cope, 1868</small>
*''Rhachianectes glaucus'' <small>Cope, 1869</small>
*''Eschrichtius gibbosus'' <small>Van Deinse & Junge, 1937</small>
*''E. glaucus'' <small>Maher, 1961</small>
}}

The '''gray whale''' ('''''Eschrichtius robustus'''''),<ref name=msw3/> also known as the '''grey whale''',<ref name=BrM>Britannica Micro.: v. IV, p. 693.</ref> is a [[baleen whale]] that migrates between feeding and breeding grounds yearly. It reaches a length of {{cvt|14.9|-|15.2|m}}, a weight of  up to {{convert|41|to|45|t|ST LT|lk=on}} and lives between 55 and 70 years, although one female was estimated to be 75–80 years of age.<ref name="CSE">[https://publications.gc.ca/collections/collection_2007/ec/En3-4-36-2007E.pdf Recovery Strategy for the Grey Whale (''Eschrichtius robustus''), Atlantic Population, in Canada]. Dsp-psd.pwgsc.gc.ca (2012-07-31). Retrieved on 2012-12-20.</ref><ref name="Springer">{{cite book |last1=Swartz |first1=Steven L. |last2=Lang |first2=Aimee  |last3=Burdin |first3=Alexander |last4=Calambokidis |first4=John |last5=Mouy |first5=Héloïse Frouin |last6=Aguilar |first6=Sergio Martínez |last7=González |first7=Fabian Rodríguez |last8=Hallé |first8=Ludovic Tenorio |last9=Thode |first9=Aaron |last10=Ramírez |first10=Jorge Urbán |last11=Weller |first11=David W. |title=Sex in Cetaceans |chapter=Gray Whale Sex, Reproductive Behavior, and Social Strategies |date=2023 |pages=499–520 |doi=10.1007/978-3-031-35651-3_21 |isbn=978-3-031-35650-6 }}</ref><ref name=Jefferson>{{cite book|last1=Jefferson|first1=Thomas A.|last2=Webber|first2=Marc A.|last3=Pitman|first3=Robert L.|url=https://books.google.com/books?id=sc-cBAAAQBAJ&dq=Fin+whale&pg=PA84|year=2015|title=Marine Mammals of the World: A Comprehensive Guide to Their Identification|publisher=Academic Press|edition=2nd|pages=84–87|isbn=978-0-12-409542-7}}</ref><ref name="Fisheries">{{Cite web|last=Fisheries|first=NOAA|date=2020-06-25|title=Gray Whale {{!}} NOAA Fisheries|url=https://www.fisheries.noaa.gov/species/gray-whale|access-date=2020-06-29|website=NOAA|language=en}}</ref> One of the longest-living Gray whales currently is a female, first sighted in 1977, and estimated to be 53–55 years old {{as of|2024|lc=yes}}.<ref>{{cite web |title=Annual Report of Gray Whale Research In Laguna San Ignacio and Bahía Magdalena, B.C.S., México During Winter 2024|url=https://graywhaleresearchmexico.org/sites/default/files/documents/lsiesp-2024-annual-report-web.pdf|access-date=2 December 2025|publisher=Gray Whale Research in Mexico}}</ref> The common name of the whale comes from the gray patches and white mottling on its dark skin.<ref>[https://web.archive.org/web/20101103142438/http://acsonline.org/factpack/graywhl.htm Gray Whale ''Eschrichtius robustus'']. American Cetacean Society</ref> Gray whales were once called devil fish because of their fighting behavior when hunted.<ref>[http://www.worldwildlife.org/species/finder/graywhale/graywhale.html Gray Whale]. Worldwildlife.org. Retrieved on 2012-12-20.</ref> The gray whale is the sole living species in the [[genus]] ''[[Eschrichtius]]''. It is the sole living genus in the [[family (biology)|family]] [[Eschrichtiidae]], however some recent studies classify it as a member of the family [[Rorqual|Balaenopteridae]]. This mammal is descended from filter-feeding whales that appeared during the [[Neogene]].

The gray whale is distributed in a Northeast Pacific (North American), and an [[endangered species|endangered]] Northwest Pacific (Asian), population. North Atlantic populations were [[local extinction|extirpated]] (perhaps by [[whaling]]) on the European coast in the 12th to 14th centuries,<ref name="van den Hurk-2025">{{Cite journal|title=Dating the first historic extirpation of a whale species: The demise of the grey whale (Eschrichtius robustus) in the eastern North Atlantic|url=https://linkinghub.elsevier.com/retrieve/pii/S0277379125004032|journal=Quaternary Science Reviews|date=December 2025|article-number=109583|volume=369|doi=10.1016/j.quascirev.2025.109583|language=en|first=Youri|last=van den Hurk|first2=Fanny|last2=Sikström|first3=Luc|last3=Amkreutz|first4=Hidde|last4=Bakker|first5=Danielle L.|last5=Buss|first6=Erik|last6=Ersmark|first7=Carlos|last7=Fernández-Rodríguez|first8=Alexander|last8=Lehouck|first9=Alfredo|last9=López|first10=Jose|last10=Martinez Cedeira|first11=Carlos|last11=Nores|first12=José Antonio|last12=Pis-Millán|first13=Ana S.L.|last13=Rodrigues|first14=Martin|last14=Seiler|first15=Camilla|last15=Speller|via=Elsevier Science Direct|publication-date=2025}}</ref> and on the American and African Atlantic coasts around the late 17th to early 18th centuries.<ref>{{Cite book|title=Encyclopedia of marine mammals |page=404 |year=2009 |publisher=Academic Press |isbn=978-0-12-373553-9|author1=Perrin, William F. |author2=Würsig, Bernd G. |author3=Thewissen, J. G. M. }}</ref> However, in the 2010s and 2020s there have been rare sightings of gray whales in the [[North Atlantic]],<ref>{{cite news |last1=Whittle |first1=Patrick |title=What is a whale native to the North Pacific doing off New England? Climate change could be the key |url=https://apnews.com/article/gray-whale-nantucket-climate-change-atlantic-28eb054f7dd05732f65d6c441fefdee8 |access-date=2024-03-27 |work=AP News |date=2024-03-05}}</ref><ref>{{cite news |last1=McCloud |first1=Cheryl |title=Gray whale spotted off Florida coast. Here's why the sighting is so unusual |url=https://www.palmbeachpost.com/story/news/2023/12/21/gray-whale-florida-miami-migration-how-identify-unusual-fwc/71997055007/ |access-date=2024-03-27 |agency=The Palm Beach Post |date=2023-12-21}}</ref> [[Mediterranean]],<ref>{{cite news |last1=Minguez |first1=Alexandre |title=Lost in the Mediterranean, a starving grey whale must find his way home soon |url=https://www.reuters.com/business/environment/lost-mediterranean-starving-grey-whale-must-find-his-way-home-soon-2021-05-07/ |access-date=2024-03-27 |work=Reuters |date=2021-05-07}}</ref><ref>{{Cite news |last=Walker |first=Matt |date=2010-06-08 |title=Mystery gray whale sighted again |url=https://news.bbc.co.uk/earth/hi/earth_news/newsid_8729000/8729064.stm |access-date=2025-01-03 |language=en-GB}}</ref><ref>{{Cite news |last=Rinat |first=Zafrir |date=May 8, 2010 |title=Lost in search of lunch: Rare Pacific whale spotted off Israel's coast |url=https://www.haaretz.com/2010-05-08/ty-article/lost-in-search-of-lunch-rare-pacific-whale-spotted-off-israels-coast/0000017f-f41a-d487-abff-f7fef19c0000 |archive-url=https://web.archive.org/web/20240515015230/https://www.haaretz.com/2010-05-08/ty-article/lost-in-search-of-lunch-rare-pacific-whale-spotted-off-israels-coast/0000017f-f41a-d487-abff-f7fef19c0000 |archive-date=2024-05-15 |access-date=2025-01-03 |work=Haaretz.com |language=en}}</ref> and even off [[South Atlantic]] coasts.<ref>{{Cite web |last=St. Lawrence |first=Chris |date=June 2024 |title=Atlantic Gray Whales: Past, Present, and Future {{!}} Smithsonian Ocean |url=https://ocean.si.edu/ocean-life/marine-mammals/atlantic-gray-whales-past-present-and-future |access-date=2025-01-03 |website=ocean.si.edu |language=en}}</ref><ref>{{Cite web |last=Tims |first=Dana |date=2024-02-10 |title=OSU researcher wonders if gray whale off Florida coast was just lost, or a sign it's 'exploring' the Atlantic |url=https://www.klcc.org/npr-science-environment/2024-02-10/osu-researcher-wonders-if-gray-whale-off-florida-coast-was-just-lost-or-a-sign-its-exploring-the-atlantic |access-date=2025-01-03 |website=KLCC {{!}} NPR for Oregonians |language=en}}</ref><ref>{{Cite web |last1=McCloud |first1=Cheryl |last2=Crowley |first2=Kinsey |date=December 21, 2023 |title=Gray whale spotted off Florida coast. Here's why the sighting is so unusual |url=https://www.palmbeachpost.com/story/news/2023/12/21/gray-whale-florida-miami-migration-how-identify-unusual-fwc/71997055007/ |access-date=2025-01-03 |website=The Palm Beach Post |language=en-US}}</ref><ref>{{Cite web |last=McCloud |first=Cheryl |date=March 6, 2024 |title=Scientists believe rare gray whale spotted off Florida has been seen again. What we know |url=https://www.palmbeachpost.com/story/news/2024/03/06/rare-gray-whale-seen-off-miami-florida-spotted-again-off-nantucket-massachusetts/72864561007/ |access-date=2025-01-03 |website=The Palm Beach Post |language=en-US}}</ref> 
{{TOC limit}}

==Taxonomy==
[[File:Gray whale skeleton.jpg|thumb|left|Skeleton]] 
The gray whale is traditionally placed as the only living species in its genus and family, ''[[Eschrichtius]]'' and [[Eschrichtiidae]],<ref name="TPBDB">[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=42976 The Paleobiology Database Eschrichtiidae entry]  accessed on 26 December 2010</ref> but an extinct species was discovered and placed in the genus in 2017, the [[Akishima whale]] (''E. akishimaensis'').<ref>{{cite journal|first1=T.|last1=Kimura|first2=Y.|last2=Hasegawa|first3=N.|last3=Kohno|year=2017|title=A new species of the genus ''Eschrichtius'' (Cetacea: Mysticeti) from the Early Pleistocene of Japan|journal=Paleontological Research|volume=22|issue=1|pages=1–19|doi=10.2517/2017PR007|s2cid=134494152|doi-access=free}}</ref> Some recent studies place gray whales as being outside the rorqual [[clade]], but as the closest relatives to the rorquals.<ref>{{cite journal|author=Seeman, Mette E.|display-authors=etal|date=December 2009|title=Radiation of extant cetaceans driven by restructuring of the ocean|journal=Systematic Biology|volume=58|issue=6|pages=573–585|doi=10.1093/sysbio/syp060|jstor=25677547|pmc=2777972|pmid=20525610}}</ref> But other recent [[DNA]] analyses have suggested that certain [[rorqual]]s 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 whale]]s.<ref>{{Cite journal|title=Cetacean mitochondrial DNA control region: sequences of all extant baleen whales and two sperm whale species|author=Arnason, U.|author2=Gullberg A.|author3=Widegren, B.|name-list-style=amp|journal=Molecular Biology and Evolution|volume=10|pages=960–970|year=1993|pmid=8412655|issue=5|doi=10.1093/oxfordjournals.molbev.a040061|doi-access=free}}</ref><ref>{{Cite journal|title=Mitochondrial phylogenetics and evolution of mysticete whales|author=Sasaki, T. |journal=Systematic Biology|volume=54|issue=1|pages=77–90|year=2005|doi=10.1080/10635150590905939|pmid=15805012|last2=Nikaido|first2=Masato|last3=Hamilton|first3=Healy|last4=Goto|first4=Mutsuo|last5=Kato|first5=Hidehiro|last6=Kanda|first6=Naohisa|last7=Pastene|first7=Luis|last8=Cao|first8=Ying|last9=Fordyce|first9=R.|last10=Hasegawa |first10=Masami |last11=Okada |first11=Norihiro |display-authors=8 |doi-access=free}}</ref><ref>{{Cite journal|last1=McGowen|first1=Michael R|last2=Tsagkogeorga|first2=Georgia|last3=Álvarez-Carretero|first3=Sandra|last4=dos Reis|first4=Mario|last5=Struebig|first5=Monika|last6=Deaville|first6=Robert|last7=Jepson|first7=Paul D|last8=Jarman|first8=Simon|last9=Polanowski|first9=Andrea|last10=Morin|first10=Phillip A|last11=Rossiter|first11=Stephen J|date=2019-10-21|title=Phylogenomic Resolution of the Cetacean Tree of Life Using Target Sequence Capture|journal=Systematic Biology|volume=69|issue=3|pages=479–501|doi=10.1093/sysbio/syz068|issn=1063-5157|pmc=7164366|pmid=31633766}}</ref><ref>{{cite journal|last1=Árnason|first1=Úlfur|last2=Lammers|first2=Fritjof|last3=Kumar|first3=Vikas|last4=Nilsson|first4=Maria A.|last5=Janke|first5=Axel|year=2018|title=Whole-genome sequencing of the blue whale and other rorquals finds signatures for introgressive gene flow|journal=[[Science Advances]]|volume=4|issue=4|article-number=eaap9873|bibcode=2018SciA....4.9873A|doi=10.1126/sciadv.aap9873|pmc=5884691|pmid=29632892}}</ref> The [[American Society of Mammalogists]] has followed this classification.<ref>{{Cite web|title=Explore the Database|url=https://www.mammaldiversity.org/explore.html#species-id=1006404|access-date=2021-08-20|website=www.mammaldiversity.org}}</ref>

[[John Edward Gray]] placed it in its own genus in 1865, naming it in honour of physician and zoologist [[Daniel Frederik Eschricht]].<ref>{{Cite journal|author= Gray |year= 1864 |title=''Eschrichtius'' |journal= Annals and Magazine of Natural History |volume=3 |issue=14 |page=350}}</ref> 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.<ref>{{cite journal|doi=10.1371/journal.pone.0021295|title=What happened to gray whales during the Pleistocene? The ecological impact of sea-level change on benthic feeding areas in the North Pacific Ocean|year=2011|editor1-last=Goswami|editor1-first=Anjali|author1-link=Nicholas Pyenson|last1=Pyenson|first1=Nicholas D.|last2=Lindberg|first2=David R.|journal=PLOS ONE|volume=6|issue=7|article-number=e21295|pmid=21754984|pmc=3130736|bibcode=2011PLoSO...621295P|doi-access=free}}</ref> The living Pacific species was described by Cope as ''Rhachianectes glaucus'' in 1869.<ref>{{Cite journal|author=Cope |year=1869|title= Rhachianectes |journal= Proceedings of the Academy of Natural Sciences of Philadelphia |volume= 21|page=15 |url=https://www.biodiversitylibrary.org/page/6587914#page/23/mode/1up }}</ref> 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.<ref>{{Cite journal|last=Cederlund |first=BA |year=1938|title= A subfossil gray whale discovered in Sweden in 1859|journal=Zoologiska Bidrag från Uppsala |volume=18 |pages= 269–286}}</ref><ref name = "sbjhnc">{{Cite book|vauthors=Mead JG, Mitchell ED |veditors=Jones ML, Swartz SL, Leatherwood S |title=The Gray Whale |year=1984|publisher= Academic Press|location= London|pages= 33–53|chapter= Atlantic gray whales}}</ref> 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.<ref name="Bryant">{{Cite journal|last=Bryant |first=PJ |year=1995|title= Dating remains of gray whales from the eastern North Atlantic|jstor=1382754|journal=Journal of Mammalogy |volume=76 |issue=3 |pages= 857–861 |doi=10.2307/1382754 |bibcode=1995JMamm..76..857B }}</ref>

Many other names have been ascribed to the gray whale, including desert whale,<ref>{{Cite journal|author=Waser, Katherine |title=Ecotourism and the desert whale: An interview with Dr. Emily Young|year=1998|url=http://ag.arizona.edu/oals/ALN/aln43/baja.html| journal=Arid Lands Newsletter}}</ref> devilfish, gray back, mussel digger and rip sack.<ref name=ITIS>{{ITIS |id=180521 |taxon=Eschrichtius robustus |access-date=March 18, 2006}}</ref> The name ''Eschrichtius gibbosus'' is sometimes seen; this is dependent on the acceptance of a 1777 description by Erxleben.<ref>{{Harvnb|Erxleben|1777|p=610}} (''Balaena gibbosa'')</ref>

=== Taxonomic history ===
A number of 18th century authors<ref>E.g. {{Harvnb|Erxleben|1777|pp=610–611}}; {{Harvnb|Anderson|1746|p=201}}; {{Harvnb|Brisson|1762|p=221}}</ref> described the gray whale as ''[[Balaena]] gibbosa'', the "whale with six bosses", apparently based on a brief note by {{Harvnb|Dudley|1725}}:<ref name="Barnes-McLeod">{{Harvnb|Barnes|McLeod|1984|pp=4–5}}</ref>

{{Blockquote|The Scrag Whale is near a kin to the Fin-back, but instead of a Fin upon his Back, the Ridge of the Afterpart of his Back is cragged with half a Dozen Knobs or Nuckles; he is nearest the right Whale in Figure and for Quantity of Oil; his Bone is white, but won't split.<ref>{{Harvnb|Dudley|1725|p=258}}</ref>}}

The gray whale was first described as a distinct species by {{Harvnb|Lilljeborg|1861}} 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]].<ref>{{Harvnb|Lilljeborg|1861|p=39}}</ref>  {{Harvnb|Gray|1864}} 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''.<ref>{{Harvnb|Gray|1864|p=351}}</ref> {{Harvnb|Van Beneden|Gervais|1868}} 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 [[Nomen dubium|nomina dubia]]) and therefore named the gray whale ''Plesiocetus robustus'', reducing Lilljeborg's and Gray's names to synonyms.<ref>{{Harvnb|Van Beneden|Gervais|1868|pp=290–291}}</ref>

[[Charles Melville Scammon]]  produced one of the earliest descriptions of living Pacific gray whales,{{sfn|Scammon|1874}} 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.<ref>{{Harvnb|Scammon|1874|loc=''The marine mammals of the north-western coast of North America''}}</ref> At this time, however, the extinct Atlantic population was considered a separate species (''Eschrischtius robustus'') from the living Pacific population (''Rhachianectes glaucus'').<ref>{{Harvnb|Bryant|1995|pp=857–859}}</ref>

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.<ref name="Barnes-McLeod" />

==Description==
[[Image:Grauwal.png|thumb]]
The gray whale has a dark slate-gray color and is covered by characteristic gray-white patterns, which are scars left by [[parasite]]s 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<ref>{{cite web|url=https://thewhaletrail.org/how-to-spot-a-whale|title=How to Spot Whales from Shore {{!}} the whale trail|website=thewhaletrail.org|date=13 February 2011 |language=en-US|access-date=2017-02-13}}</ref> at the surface in calm wind conditions.

Gray whales measure from {{convert|4.6|-|4.9|m|ft|abbr=on|0}} in length for newborns to {{convert|11|-|15.2|m|ft|abbr=on}} 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 {{convert|40|-|45|tonne|ST}}, with a typical range of {{convert|15|-|33|t|ST|abbr=on}}, making them the ninth largest sized species of cetacean.<ref name="CSE" /><ref name="Burnie">Burnie D. and Wilson D.E. (eds.) (2005) ''Animal: The Definitive Visual Guide to the World's Wildlife''. DK Adult, {{ISBN|0789477645}}</ref><ref name=Jefferson /><ref name=Lockyer_1976>{{cite journal | author1=Lockyer, C. | title=Body weights of some species of large whales | journal=[[J. Cons. Int. Explor. Mer]] | volume=36 | issue=3 | pages=259–273 | date=1976| doi=10.1093/icesjms/36.3.259 }}</ref>

[[Image:GrayWhaleByPhilKonstantin.jpg|thumb|A close-up of a gray whale's double blow hole and some of its encrusted barnacles]]

Notable features that distinguish the gray whale from other [[Mysticeti|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 {{cvt|5|-|40|cm}} in length.<ref name=Jefferson /> Small depressions on the upper jaw each contain a lone stiff hair, but are only visible on close inspection. Its head's ventral surface lacks the numerous prominent furrows of the related rorquals, instead bearing two to five shallow furrows on the throat's underside. The gray whale also lacks a [[dorsal fin]], instead bearing 6 to 12 dorsal crenulations ("knuckles"), which are raised bumps on the midline of its rear quarter, leading to the [[fluke (tail)|fluke]]s. This is known as the [[dorsal ridge]]. The tail itself is {{convert|3|-|4|m|ft|abbr=on|0}} across and deeply notched at the center while its edges taper to a point.<ref name="Alaska-Department">{{Cite web|url=https://www.adfg.alaska.gov/index.cfm?adfg=graywhale.printerfriendly|title = Gray Whale (Eschrichtius robustus) Printer Friendly|date = March 16, 2026}}</ref> The gray whale's penis can reach at least {{cvt|1.7|m}} in length.<ref>{{cite web |last1=Paxtona |first1=C. G. M. |last2=Knatterud |first2=E. |last3=Hedley |first3=Sharon |year=2005 |title=Cetaceans, sex and sea serpents: an analysis of the Egede accounts of a “most dreadful monster” seen off the coast of Greenland in 1734 |journal=Archives of Natural History |volume=32 |issue=1 |pages=1–9 |doi=10.3366/anh.2005.32.1.1 | s2cid=83523994 |url=https://www.sciencefriday.com/wp-content/uploads/2016/04/Cetaceans-Sex-and-Sea-Serpents.pdf }}</ref> Its movement speed is slow, about {{convert|5|-|8|km/h|mph|abbr=on|0}}, but it can reach speeds of up to {{convert|16|-|17.5|km/h|mph|abbr=on|0}} when in danger.<ref name=Alaska-Department />

There has been a record of rather aggressive interspecies interactions between a [[North Pacific right whale]] and a pod of grey whales off California, making it the only record of possible interspecies aggression among baleen whales,<ref>[http://www.sfcelticmusic.com/js/rtwhales/WestCoast_sightings.htm/ Records of North Pacific Right Whales along the coasts of California, Baja, Oregon and Washington] {{webarchive|url=https://web.archive.org/web/20120421045620/http://www.sfcelticmusic.com/js/RTWHALES/WestCoast_sightings.htm |date=April 21, 2012 }}. Jim Scarff's Eclectic Home Page. Retrieved March 16, 2026.</ref> but there have been an observation of social behaviors between the two species on Sakhalin.<ref>Shipulin 2012 [http://shipulin.livejournal.com/13877.html А давайте я вам китов покажу, а?] {{Webarchive|url=https://web.archive.org/web/20160111081541/http://shipulin.livejournal.com/13877.html |date=January 11, 2016 }}. [[LiveJournal]]. Retrieved March 16, 2026</ref>

===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.<ref name=SC65bBRG12 /><ref name=GrayJapan>{{Cite journal|author1=Nakamura G.|author2=Kato H.|title=日本沿岸域に近年（1990–2005 年）出現したコククジラEschrichtius robustus の骨学的特徴，特に頭骨形状から見た北太平洋西部系群と東部系群交流の可能性|url=https://www.jstage.jst.go.jp/article/mammalianscience/54/1/54_73/_article/-char/ja/|journal=哺乳類科学 |volume=54 |issue=1 |year=2014|pages=73–88|publisher=The Mammal Society of Japan, Cetacean Research Laboratory in Marine environmental section in the Graduate School of [[Tokyo University of Marine Science and Technology]], [[J-STAGE]]|format=PDF|access-date=2015-01-16}}</ref> 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.<ref name=Olga2011>Shpak O. (2011). [http://kit.sevin-expedition.ru/news/news_81.html Observation of the gray whale in the Laptev Sea]. Standing expedition of IEE Russian Academy of Sciences.</ref> This corresponds with the DNA analysis of last recorded stranding in China.<ref name=2011insights /> Differences were also observed between Korean and Chinese specimens.<ref name=GrayJapan/>

==Populations==

===North Pacific===
[[Image:Eschrichtius robustus 01-cropped.jpg|thumb|Gray whale [[whale surfacing behaviour|breaching]]]]
[[Image:Spouting gray whale Yachats, OR (8008163164).jpg|thumb|Gray whale spouting along shores of [[Yachats, Oregon]]]]
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]].<ref name="fisheries.noaa.gov">{{Cite web |last=Fisheries |first=NOAA |date=2023-04-13 |title=Gray Whale {{!}} NOAA Fisheries |url=https://www.fisheries.noaa.gov/species/gray-whale |access-date=2024-11-22 |website=NOAA |language=en}}</ref> 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."<ref name=BANG/>

The western population has had a very slow growth rate despite heavy conservation action over the years, likely due to their very slow reproduction rate.<ref name="The Maritime Executive" /> The state of the population hit an all-time low in 2010, when no new reproductive females were recorded, resulting in a minimum of 26 reproductive females being observed since 1995.<ref name="iwcoffice.org">{{cite web|title=Report of the Scientific Committee, Tromsø, Norway, 30 May to 11 June 2011 Annex F: Sub-Committee on Bowhead, Right and Gray Whale |url=http://www.iwcoffice.org/_documents/sci_com/SCRepFiles2011/Annex%20F%20-%20BRG.pdf |work=IWC Office |archive-url=https://web.archive.org/web/20111105190412/http://www.iwcoffice.org/_documents/sci_com/SCRepFiles2011/Annex%20F%20-%20BRG.pdf |archive-date=5 November 2011 }}</ref> Even a very small number of additional annual female deaths will cause the subpopulation to decline.<ref name="IUCN Western">{{cite iucn | author1 = Cooke, J.G. | author2 = Taylor, B.L. | author3 = Reeves, R. | author4 = Brownell Jr., R.L. | name-list-style = amp | title = ''Eschrichtius robustus'' (western subpopulation) | article-number = e.T8099A50345475 | year = 2018 | access-date = 2 June 2021}}</ref> However, as of 2018, evidence has indicated that the western population is markedly increasing in number, especially off [[Sakhalin|Sakhalin Island]]. Following this, the IUCN downlisted the population's conservation status from [[critically endangered]] to [[Endangered species|endangered]].<ref>{{Cite news|url=https://phys.org/news/2018-11-fin-whale-mountain-gorilla-populations.html|title=Fin whale, mountain gorilla populations rise amid conservation action|access-date=2018-11-25}}</ref><ref name="The Maritime Executive">{{Cite news|url=https://www.maritime-executive.com/article/whale-conservation-success-highlighted-in-iucn-red-list-update|title=Whale Conservation Success Highlighted in IUCN Red List Update|work=The Maritime Executive|access-date=2018-11-25|language=en}}</ref>

===North Atlantic===
The gray whale became extinct in the North Atlantic in the 18th century.<ref>{{Cite book|author= Rice DW |title=Marine Mammals of the World. Systematics and Distribution. Special Publication Number 4. |year= 1998 |publisher= The Society for Marine Mammalogy|location= Lawrence, Kansas }}</ref> They had been seasonal migrants to coastal waters of both sides of Atlantic, including the [[Baltic Sea]],<ref>Jones L.M..Swartz L.S.. Leatherwood S.. [https://books.google.com/books?id=GfGITi5NmJoC&dq=bothnia+whale&pg=PA41 The Gray Whale: Eschrichtius Robustus]. "Eastern Atlantic Specimens". pp 41–44. [[Academic Press]]. Retrieved on September 5, 2017</ref><ref>[[Global Biodiversity Information Facility]]. [https://www.gbif.org/occurrence/1322462463 Occurrence Detail 1322462463]. Retrieved on September 21, 2017</ref> the [[Wadden Sea]], the [[Gulf of St. Lawrence]], the [[Bay of Fundy]], [[Pamlico Sound]] and possibly [[Hudson Bay]].<ref>{{cite web |url=http://www.fmap.ca/ramweb/media/biodiversity_loss/downloads/RegionalExtinctionExamples.pdf |archive-url=https://wayback.archive-it.org/all/20110425162323/http://www.fmap.ca//ramweb/media/biodiversity_loss/downloads/RegionalExtinctionExamples.pdf |archive-date=2011-04-25 |title=Regional Species Extinctions – Examples of regional species extinctions over the last 1000 years and more |work=Census of Marine Life |access-date=2014-07-05 }}</ref><ref>[[Fisheries and Oceans Canada]].
 2016. [http://www.dfo-mpo.gc.ca/species-especes/profiles-profils/grey-whale-a-baleine-grise-a-eng.html Grey Whale (Atlantic population) Eschrichtius robustus]. Retrieved on August 15, 2017</ref> 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.<ref name="Bryant" /> A 2025 study determined that grey whales became extirpated in the eastern North Atlantic around in the 12th to 14th centuries and put the cause as partly due to environmental factors as it coincided with the end of the [[Medieval Warm Period|Medieval Warm period]] and medieval whaling as its extirpation coincided with the height of medieval whaling.<ref name="van den Hurk-2025" /> Remains dating from the Roman epoch were found in the [[Mediterranean]] during excavation of the antique harbor of [[Lattara]] near [[Montpellier]], France, in 1997, raising the question of whether Atlantic gray whales migrated up and down the coast of Europe from the Wadden Sea to calve in the Mediterranean.<ref>{{Cite journal|year= 2003 |title=Did the Gray Whale calve in the Mediterranean? |journal= Lattara|volume= 16|pages=153–164 |author = Macé M.|url=https://archive.org/details/DidTheGrayWhaleEschrichtiusRobustusCalveInTheMediterranean}}</ref><ref name=SpeciesMatters>The MORSE Project – [http://morse.cefe.cnrs.fr/?p=84. Ancient whale exploitation in the Mediterranean: species matters] {{Webarchive|url=https://web.archive.org/web/20161220073138/http://morse.cefe.cnrs.fr/?p=84. |date=2016-12-20 }}</ref> 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 whale]]s), confirming that gray whales once ranged into the Mediterranean.<ref>{{cite journal |title=Forgotten Mediterranean calving grounds of grey and North Atlantic right whales: evidence from Roman archaeological records |author=Ana S. L. Rodrigues |author2=Anne Charpentier |author3=Darío Bernal-Casasola |author4=Armelle Gardeisen |author5=Carlos Nores |author6=José Antonio Pis Millán |author7=Krista McGrath |author8=Camilla F. Speller |date=July 11, 2018 |journal=Proceedings of the Royal Society B |volume=285 |issue=1882 |doi=10.1098/rspb.2018.0961 |pmid=30051821 |pmc=6053924 |doi-access=free }}</ref> 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 (town), New York|Southampton, New York]], to [[Jupiter Island, Florida]], the latest from 1675.<ref name="sbjhnc"/> In his 1835 history of [[Nantucket Island]], Obed Macy wrote that in the early pre-1672 colony a whale of the kind called "scragg" entered the harbor and was pursued and killed by the settlers.<ref name="Macy O 1835">{{Cite book|author= Macy O|url=https://babel.hathitrust.org/cgi/pt?id=njp.32101067881282;view=1up;seq=7 |title=The History of Nantucket:being a compendious account of the first settlement of the island by the English:together with the rise and progress of the whale fishery, and other historical facts relative to said island and its inhabitants:in two parts |year=1835 |publisher= Hilliard, Gray & Co. |location= Boston |isbn=1-4374-0223-2 }}</ref> 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.<ref name="Van Deinse 1937 161–188">{{Cite journal|last= Van Deinse |first= AB |year= 1937 |title=Recent and older finds of the gray whale in the Atlantic |journal= Temminckia |volume= 2 |pages=161–188 }}</ref><ref name="Dudley 1725 256–259">{{Cite journal|last= Dudley |first= P |year= 1725 |title=An essay upon the natural history of whales |journal= Philosophical Transactions of the Royal Society |volume=33 |pages=256–259 |url=https://archive.org/details/philtrans04271050|jstor=103782|doi= 10.1098/rstl.1724.0053|issue= 381–391 |bibcode= 1724RSPT...33..256D|s2cid= 186208376 }}</ref>

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]].<ref name=wnyc>{{cite web|title=The Gray Whale Sneaks Back into the Atlantic, Two Centuries Later|author=Hamilton, Alex|url=https://www.wnyc.org/story/extinct-gray-whale-population-may-reappear-atlantic/|access-date=2019-10-28|date=October 8, 2015|publisher=WNYC}}</ref><ref name=discover>{{cite magazine|title=Why Are Gray Whales Moving to the Ocean Next Door?|author=Schiffman, Richard|date=February 25, 2016|access-date=2019-10-28|url=http://discovermagazine.com/2016/april/13-why-are-gray-whales-moving-to-the-ocean-next-door|magazine=Discover Magazine}}</ref> These were presumably migrants from the North Pacific population through the [[Arctic Ocean]].<ref name=wnyc/><ref name=discover/> A 2015 study of DNA from [[subfossil]] gray whales indicated that this may not be a historically unique event.<ref name=wnyc/><ref name=discover/><ref name=alter>{{cite journal|title=Climate impacts on transocean dispersal and habitat in gray whales from the Pleistocene to 2100 |author=Alter, S. Elizabeth |author2=Hofreiter, Michael|display-authors=etal|date=March 9, 2015|doi=10.1111/mec.13121|journal=Molecular Ecology|volume=24|issue=7|pages=1510–1522|pmid=25753251|bibcode=2015MolEc..24.1510A |s2cid=17313811|url=https://publishup.uni-potsdam.de/frontdoor/index/index/docId/43892}}</ref> 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.<ref name=wnyc/><ref name=discover/><ref name=alter/> These migrations corresponded to times of relatively high temperatures in the Arctic Ocean.<ref name=wnyc/><ref name=discover/><ref name=alter/> In 2021, one individual was seen in the port of [[Rabat]], [[Morocco]],<ref name=
SOS-D>SOS Dolfijn, 2021, [https://www.sosdolfijn.nl/nieuws/archief/grijze-walvis-gemeld-bij-marokko Grijze walvis gemeld bij Marokko]</ref> followed by sightings in [[Algeria]]<ref name=ObservationORG>Observation.org, [https://observation.org/observation/211419906/ 2021-04-04, Archive – Yasutaka Imai]</ref> and [[Italy]].<ref name=Italy24/> In March 2024, [[New England Aquarium]] researchers photographed a gray whale {{convert|30|mi|km}} south of [[Nantucket, Massachusetts]].<ref name="AP 2024-03-06">{{cite news |agency=Associated Press |title=Gray whale sighted off New England 200 years after species' Atlantic extinction |website=The Guardian |date=2024-03-06 |url=https://www.theguardian.com/environment/2024/mar/06/gray-whale-nantucket-extinction |access-date=2024-03-06}}</ref>

===Pre-whaling abundance===
Researchers<ref>{{Cite journal|last1= Alter |first1= SE |date=May 2012 |title=Pre-Whaling Genetic Diversity and Population Ecology in Eastern Pacific Gray Whales: Insights from Ancient DNA and Stable Isotopes |journal= PLOS ONE |volume= 7 |issue= 5 |article-number= e35039 |last2= Newsome |first2= SD |last3= Palumbi |first3= SR |author-link3= Stephen Palumbi |doi= 10.1371/journal.pone.0035039 |pmid= 22590499 |pmc=3348926|bibcode= 2012PLoSO...735039A |doi-access= free }}</ref> 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.<ref>{{cite journal |last1=Alter |first1=S. E. |last2=Rynes |first2=E. |last3=Palumbi |first3=S. R. |title=DNA evidence for historic population size and past ecosystem impacts of gray whales |journal=Proceedings of the National Academy of Sciences |date=11 September 2007 |volume=104 |issue=38 |pages=15162–15167 |doi=10.1073/pnas.0706056104 |pmid=17848511 |pmc=1975855 |bibcode=2007PNAS..10415162A |doi-access=free }}</ref> 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 of 1972|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.<ref>{{cite web|title=Gray Whale Population Studies|url=http://swfsc.noaa.gov/textblock.aspx?Division=PRD&ParentMenuId=211&id=9036|publisher=NOAA, National Marine Fisheries Service, Southwest Fisheries Science Center, Protected Resource Division|year=2010|access-date=2011-02-25}}</ref> Factors limiting or threatening current population levels include ship strikes, entanglement in fishing gear, and changes in sea-ice coverage associated with climate change.<ref>{{cite web|title=Automatic Whale Detector|url=http://www.fisheries.noaa.gov/stories/2015/02/gray_whale_survey_thermal_imaging.html|publisher=NOAA, National Marine Fisheries Service, Southwest Fisheries Science Center, Protected Resource Division|year=2015|access-date=2016-01-17|archive-url=https://web.archive.org/web/20160223203354/http://www.fisheries.noaa.gov/stories/2015/02/gray_whale_survey_thermal_imaging.html|archive-date=2016-02-23}}</ref>

===Integration and recolonization===
[[File:Gray whale calf by Marc Webber USFWS.jpg|thumb|Calf with mouth open showing baleen, Alaska]]
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.<ref>{{cite web|title=Western Pacific Gray Whale, Sakhalin Island 2010|date=February 2011|url=http://mmi.oregonstate.edu/Sakhalin2010|publisher=Oregon State University, Marine Mammal Institute|access-date=2011-02-25|archive-date=2013-03-25|archive-url=https://web.archive.org/web/20130325022649/http://mmi.oregonstate.edu/Sakhalin2010}}</ref> 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.<ref name=SC65bBRG12>{{cite report|author=Kato H.|author2=Kishiro T.|author3=Nishiwaki S.|author4=Nakamura G.|author5=Bando T.|author6=Yasunaga G.|author7=Sakamoto T. |author8=Miyashita T.|year=2014| title=Status Report of Conservation and Researches on the Western North Pacific Gray Whales in Japan, May 2013 – April 2014 [document SC/65b/BRG12]|url=https://archive.iwc.int/pages/download.php?ref=4801&size=&ext=pdf&k=&alternative=-1&usage=-1&usagecomment=|access-date=2021-08-21}}</ref><ref name=2011insights />

In mid-1980, there were three gray whale sightings in the eastern [[Beaufort Sea]], placing them {{convert|585|km|mi|sp=us}} further east than their known range at the time.<ref>{{Cite journal|title=Gray Whale (''Eschrichtius robustus'') Sightings in Eastern Beaufort Sea |doi=10.14430/arctic2521|author1=Rugh, David J.  |author2=Fraker, Mark A. |journal=Arctic |volume=34|issue=2|date=June 1981 |url=http://pubs.aina.ucalgary.ca/arctic/Arctic34-2-186.pdf |archive-url=https://web.archive.org/web/20120422023641/http://pubs.aina.ucalgary.ca/arctic/Arctic34-2-186.pdf |archive-date=2012-04-22 |url-status=live |access-date=2010-07-15 }}</ref> 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]],<ref>{{cite journal |author1=Shpak V.O. |author2=Kuznetsova M.D. |author3=Rozhnov V.V. | year = 2013 | title = Observation of the Gray Whale (''Eschrichtius robustus'') in the Laptev Sea | journal = Biology Bulletin | volume = 40 | issue = 9 | pages = 797–800 | doi = 10.1134/S1062359013090100|bibcode=2013BioBu..40..797S |s2cid=18169458 }}</ref> and around the marine mammal sanctuary<ref>Nefedova T., Gavrilo M., Gorshkov S. (2013). [http://www.rgo.ru/ru/article/letom-v-arktike-stalo-menshe-lda Летом в Арктике стало меньше льда] {{webarchive|url=https://web.archive.org/web/20140524004126/http://www.rgo.ru/ru/article/letom-v-arktike-stalo-menshe-lda |date=2014-05-24 }}. Russian Geographical Society. retrieved on 24-05-2014</ref> of the [[Franz Josef Land]],<ref>Elwen H.S., Gridley T. (2013). [http://www.namibiandolphinproject.com/wp-content/uploads/2013/06/Elwen-Gridley_Gray-whale-in-Namibia-20130610.pdf Gray whale (''Eschrichtius robustus'') sighting in Namibia (SE Atlantic) – first record for Southern Hemisphere]. Mammal Research Institute, the [[University of Pretoria]] and the Namibian Dolphin Project. retrieved on 18-05-2014</ref> indicating possible earlier pioneers of re-colonizations. These whales were darker in body color than those whales seen in Sea of Okhotsk.<ref name=Olga2011/> In May 2010, a gray whale was sighted off the Mediterranean shore of Israel.<ref>{{cite web |author=צפריר רינת 08.05.2010 16:47 עודכן ב: 16:50 |url=https://www.haaretz.co.il/hasite/spages/1167822.html |title=לווייתן אפור נצפה בפעם הראשונה מול חופי ישראל – מדע וסביבה – הארץ |publisher=Haaretz.co.il |access-date=2012-06-26 |archive-url=https://web.archive.org/web/20100511063628/http://www.haaretz.co.il/hasite/spages/1167822.html |archive-date=2010-05-11 }}</ref> 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".<ref name="esa">{{cite web
| url=http://www.esa.int/esaCP/SEMYTC13J6F_index_0.html
| title=Satellites witness lowest Arctic ice coverage in history|work=European Space Agency 
| access-date=2007-09-14}}</ref> The same whale was sighted again on May 30, 2010, off the coast of [[Barcelona]], Spain.<ref name="June Spotting">{{cite news|url=https://news.bbc.co.uk/earth/hi/earth_news/newsid_8729000/8729064.stm|title=Mystery gray whale sighted again off Spain coast|last=Walker|first=Matt|date=30 May 2010|work=BBC News|access-date=8 June 2010}}</ref>

In May 2013, a gray whale was sighted off [[Walvis Bay]], Namibia. Scientists from the Namibian Dolphin Project confirmed the whale's identity and thus provides the only sighting of this species in the Southern Hemisphere. Photographic identification suggests that this is a different individual than the one spotted in the Mediterranean in 2010. As of July 2013, the Namibian whale was still being seen regularly.<ref>[http://namibiandolphinproject.blogspot.ch/2013/05/a-rare-and-mysterious-visitor-in-walvis.html Namibian Dolphin Project: A rare and mysterious visitor in Walvis Bay]. Namibiandolphinproject.blogspot.ch (2013-05-14). Retrieved on 2013-07-28.</ref>

In March 2021, a gray whale was sighted near [[Rabat]], the capital of [[Morocco]].<ref name=
SOS-D /> In April, additional sightings were made off [[Algeria]]<ref name=ObservationORG/> and [[Italy]].<ref name=Italy24>{{Cite web|url=https://www.italy24news.com/News/19045.html|archive-url=https://web.archive.org/web/20210416001548/https://www.italy24news.com/News/19045.html|url-status=usurped|archive-date=April 16, 2021|title=Ponza, a gray whale sighted for the first time in Italy|date=April 15, 2021|website=Italy24 News English}}</ref>

In December 2023, a gray whale was sighted off [[Sunny Isles Beach, Florida]].<ref>{{cite news |url=https://www.palmbeachpost.com/story/news/2023/12/21/gray-whale-florida-miami-migration-how-identify-unusual-fwc/71997055007/ |title=Gray whale spotted off Florida coast. Here's why the sighting is so unusual |date=2023-12-21 |newspaper=The Palm Beach Post |last1=McCloud |first1=Cheryl |last2=Crowley |first2=Kinsey |access-date=2023-12-21}}</ref>

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.<ref name=Alter/>

==Life history==
[[Image:Whale with Laguna Peak, California, in background.jpg|thumb|A whale swims off the coast near the [[Santa Monica Mountains]].]]

===Reproduction===
{{See also|Whale reproduction}}
[[File:Embryos of Eschrichtius robustus (illustrations) and outline of head showing spouthole in 1874 detail, from- The marine mammals of the north-western coast of North America (Plate III) BHL16226079 (cropped).jpg|thumb|[[Embryo]]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.<ref name="The Grey Whale">{{cite journal|url=http://spo.nmfs.noaa.gov/mfr464/mfr4643.pdf |archive-url=https://web.archive.org/web/20081031201305/http://spo.nmfs.noaa.gov/mfr464/mfr4643.pdf |archive-date=2008-10-31 |url-status=live |author=Rice, D. |author2=Wolman, A. |author3=Braham, H. |name-list-style=amp |year=1984 |title=The Gray Whale, ''Eschrichtius robustus'' |journal=Marine Fisheries Review |volume=46 |issue=4 |pages=7–14}}</ref><ref name="Fisheries"/><ref>{{cite book |last1=Koski |first1=William R. |last2=George |first2=J. Craig  |last3=Würsig |first3=Bernd |title=Sex in Cetaceans |chapter=Bowhead Whale Reproductive Strategies |date=2023 |pages=521–541 |doi=10.1007/978-3-031-35651-3_22 |isbn=978-3-031-35650-6 }}</ref><ref name=Springer /> Females show highly synchronized reproduction, undergoing oestrus in late November to early December.<ref name="Gray-Whale">{{cite journal|url=http://lsiecosystem.org/wp-content/uploads/2010/07/Jones-Gray-Whale-Calf-Production-byPhoto-ID-Analysis-1984.jpg.pdf |journal=Rep. Int. Whal. Comm. |issue=t2 |page=177 |author=Jones, Mary Lou |title=The Reproductive Cycle in Gray Whales Based on Photographic Resightings of Females on the Breeding Grounds from 1977–82 |archive-url=https://web.archive.org/web/20120426022201/http://lsiecosystem.org/wp-content/uploads/2010/07/Jones-Gray-Whale-Calf-Production-byPhoto-ID-Analysis-1984.jpg.pdf |archive-date=2012-04-26 }}</ref> During the breeding season, it is common for females to have several mates.<ref Name="Swartz-Rugh-Taylor">{{cite journal|url=http://lsiecosystem.org/wp-content/uploads/2010/07/Swartz-Rugh-Taylor-GW-Stock-ID-June-06.pdf |title=Gray whale ''Eschrichtius robustus'' population and stock identity |doi=10.1111/j.1365-2907.2006.00082.x |year=2006 |last1=Swartz |first1=Steven L. |last2=Taylor |first2=Barbara L. |last3=Rugh |first3=David J. |journal=Mammal Review |volume=36 |pages=66–84 |issue=1 |bibcode=2006MamRv..36...66S |archive-url=https://web.archive.org/web/20120426022248/http://lsiecosystem.org/wp-content/uploads/2010/07/Swartz-Rugh-Taylor-GW-Stock-ID-June-06.pdf |archive-date=2012-04-26 }}</ref> This single ovulation event is believed to coincide with the species' annual migration patterns, when births can occur in warmer waters.<ref Name="Swartz-Rugh-Taylor"/> Most females show biennial reproduction, although annual births have been reported.<ref name="Gray-Whale"/> Males also show seasonal changes, experiencing an increase in testes mass that correlates with the time females undergo oestrus.<ref Name="Swartz-Rugh-Taylor"/> There have been reports of males displaying aggressive behavior toward females who have given birth that year, sometimes resulting in injury or death.<ref name="Springer"/> Currently there are no accounts of twin births, although an instance of twins ''in utero'' has been reported.<ref name="Gray-Whale"/>

The gestation period for gray whales is approximately 13&nbsp;{{frac|1|2}} months, with females giving birth every one to three years.<ref name="The Grey Whale"/><ref>{{Cite web |last= |title=Gray Whale {{!}} The Marine Mammal Center |url=https://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals/cetaceans/gray-whale |access-date=2024-11-22 |website=www.marinemammalcenter.org |language=en}}</ref> 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.<ref name="The Grey Whale"/> The calf is born tail first, and measures about 14–16&nbsp;ft in length, and a weight of 2,000&nbsp;lbs.<ref name="Fisheries"/> Females lactate for approximately seven months following birth, at which point calves are weaned and maternal care begins to decrease.<ref name="The Grey Whale"/> The shallow lagoon waters in which gray whales reproduce are believed to protect the newborn from [[shark]]s and [[orca]]s.<ref>{{cite web|url=http://www.graywhalefoundation.org/gray-whales.htm|title=The Gray Whale Foundation|last=Solutions|first=Gray Whale Foundation {{!}} Rosodigital Creative|website=www.graywhalefoundation.org|language=en|access-date=2018-02-02|archive-url=https://web.archive.org/web/20180203064444/http://www.graywhalefoundation.org/gray-whales.htm|archive-date=2018-02-03}}</ref><ref name=BANG/>

On 7 January 2014, a pair of newborn or aborted [[conjoined twin]] gray whale calves were found dead in the Laguna Ojo de Liebre (Scammon's Lagoon), off the west coast of Mexico. They were joined by their bellies.<ref>{{Cite web|url=http://www.independent.co.uk/environment/nature/conjoined-gray-whale-calves-discovered-in-mexican-lagoon-could-be-worlds-first-ever-documented-find-9046110.html |title=Conjoined gray whale calves discovered in Mexican lagoon could be|date=January 8, 2014|website=The Independent}}</ref>

===Feeding===
[[File:Gray-Whale-Collage.jpg|thumb|left|Gray whale breaching off the coast of [[Santa Barbara, California|Santa Barbara]], [[California]]]]
The whale feeds mainly on [[benthos|benthic]] [[crustacean]]s (such as [[amphipod]]s and [[Neotrypaea californiensis|ghost shrimp]]),<ref name="Kidd">{{Cite web|url=https://animaldiversity.org/accounts/Eschrichtius_robustus/|title=Eschrichtius robustus (gray whale)|first=Travis|last=Kidd|website=Animal Diversity Web}}</ref> 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 worm]]s, [[Clupea pallasii|herring]] eggs, various forms of larvae, and small fish.<ref name="Kidd"/>

Gray whales feed benthically, by diving to the ocean floor and rolling on to their side, (like blue whales, gray whales seem to favor rolling onto their right side) and suck up prey from the sea floor.<ref>Oliver, J. S., Slattery, P. N., Silberstein, M. A., & O'Connor, E. F. (1981). A Comparison of Gray Whale, Eschrichtius robustus, Feeding in the Bering Sea and Baja California. Fishery Bulletin, 81(3), 513–522.</ref> Gray whales seem to favor feeding planktonically in their feeding grounds, but benthically along their migration route in shallower water.<ref>{{cite journal |last1=Newell |first1=Carrie L. |last2=Cowles |first2=Timothy J. |title=Unusual gray whale ''Eschrichtius robustus'' feeding in the summer of 2005 off the central Oregon Coast |journal=Geophysical Research Letters |date=30 November 2006 |volume=33 |issue=22 |pages=L22S11 |doi=10.1029/2006GL027189 |bibcode=2006GeoRL..3322S11N |doi-access=free }}</ref> 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.<ref>Dunham, J. S., & Duffus, D. A. (2001). Foraging patterns of gray whales in central Clayoquot Sound, British Columbia, Canada. Marine Ecology Progress Series, 223, 299–310.</ref> Feeding areas during migration seem to include the Gulf of California, Monterey Bay and Baja California Sur.<ref>{{cite journal |last1=Moore |first1=Sue E. |last2=Wynne |first2=Kate M. |last3=Kinney |first3=Jaclyn Clement |last4=Grebmeier |first4=Jacqueline M. |author-link4=Jacqueline M. Grebmeier|title=Gray Whale Occurrence and Forage Southeast of Kodiak, Island, Alaska |journal=Marine Mammal Science |date=April 2007 |volume=23 |issue=2 |pages=419–428 |doi=10.1111/j.1748-7692.2007.00102.x |doi-access=free |bibcode=2007MMamS..23..419M }}</ref> Calf gray whales drink {{convert|50|-|80|lb|kg|abbr=on}} of their mothers' 53% fat milk per day.<ref>{{cite web|url=http://www.enchantedlearning.com/subjects/whales/species/Graywhale.shtml |title=GRAY WHALE: ZoomWhales.com |publisher=Enchantedlearning.com |access-date=2012-06-26}}</ref>

The main feeding habitat of the western Pacific subpopulation is the shallow ({{convert|5|-|15|m|ft|abbr=on|adj=on}} depth) shelf off northeastern [[Sakhalin Island]], particularly off the southern portion of Piltun Lagoon, where the main prey species appear to be [[amphipods]] and [[isopod]]s.<ref name=Weller1999/> In some years, the whales have also used an offshore feeding ground in {{convert|30|-|35|m|ft|abbr=on|adj=on}} depth southeast of Chayvo Bay, where benthic amphipods and [[cumaceans]] are the main prey species.<ref>Fadeev V.I. (2003). [http://www.sakhalinenergy.com/media/7d6c01c0-eb66-4ddf-a0df-31056cb622fe.pdf Benthos and prey studies in feeding grounds of the Okhotsk-Korean population of gray whales] {{Webarchive|url=https://web.archive.org/web/20170106174608/http://www.sakhalinenergy.com/media/7d6c01c0-eb66-4ddf-a0df-31056cb622fe.pdf |date=2017-01-06 }}. Final report on materials from field studies on the research vessel Nevelskoy in 2002. Marine Biology Institute, Vladivostok.</ref> Some gray whales have also been seen off western Kamchatka, but to date all whales photographed there are also known from the Piltun area.<ref name="IUCN Western"/><ref name=Reeves/>

[[File:Feeding mechanism of Eschrichtius robustus.svg|center|1200px]]
<div style="text-align:center;">
Diagram of the gray whale seafloor feeding strategy
</div>

[[File:Gray whale feeding at Yaquina Head.webm|thumb|A gray whale feeding near [[Yaquina Head]], Oregon]]
[[File:Greywhale845.jpg|thumb|right|A gray whale viewed from above]]

===Migration===
Predicted distribution models indicate that overall range in the [[last glacial period]] was broader or more southerly distributed, and inhabitations in waters where species presences lack in present situation, such as in southern hemisphere and south Asian waters and northern Indian Ocean were possible due to feasibility of the environment on those days.<ref name=Alter>{{cite journal|doi=10.1111/mec.13121 |pmid=25753251 |title=Climate impacts on transocean dispersal and habitat in gray whales from the Pleistocene to 2100 |journal=Molecular Ecology |volume=24 |issue=7 |year=2015 |last1=Alter |first1=S. Elizabeth |last2=Meyer |first2=Matthias |last3=Post |first3=Klaas |last4=Czechowski |first4=Paul |last5=Gravlund |first5=Peter |last6=Gaines |first6=Cork |last7=Rosenbaum |first7=Howard C. |last8=Kaschner |first8=Kristin |last9=Turvey |first9=Samuel T. |last10=Van Der Plicht |first10=Johannes |last11=Shapiro |first11=Beth |last12=Hofreiter |first12=Michael |pages=1510–1522 |bibcode=2015MolEc..24.1510A |s2cid=17313811 |url=https://publishup.uni-potsdam.de/frontdoor/index/index/docId/43892 }}</ref> 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.<ref name=Swartz2018>{{cite book |doi=10.1016/B978-0-12-804327-1.00140-0 |isbn=978-0-12-804327-1 |chapter=Gray Whale |title=Encyclopedia of Marine Mammals |year=2018 |last1=Swartz |first1=Steven L. |pages=422–428 }}</ref><ref>{{cite web | url=https://www.livescience.com/50487-western-gray-whale-migration.html | title=Gray Whale Breaks Mammal Migration Record | date=15 April 2015 | publisher=[[Live Science]] | access-date=15 July 2025}}</ref>

====Eastern Pacific population====
[[Image:Anim1723 - Flickr - NOAA Photo Library.jpg|thumb|A gray whale breaching in a lagoon on the coast of Mexico]]
Each October, as the northern ice pushes southward, small groups of eastern gray whales in the eastern Pacific start a two- to three-month, {{convert|8000|-|11000|km|mi|abbr=on}} trip south. Beginning in the [[Bering Sea|Bering]] and [[Chukchi Sea|Chukchi]] seas and ending in the warm-water [[lagoon]]s 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.<ref>{{cite journal |last1=Pike |first1=Gordon C. |title=Migration and Feeding of the Gray Whale (''Eschrichtius gibbosus'') |journal=Journal of the Fisheries Research Board of Canada |date=1 May 1962 |volume=19 |issue=5 |pages=815–838 |doi=10.1139/f62-051 |bibcode=1962JFRBC..19..815P }}</ref>

Traveling night and day, the gray whale averages approximately {{convert|120|km|mi|abbr=on}} per day at an average speed of {{convert|8|km/h|mph|abbr=on|0}}. This round trip of {{convert|16000|-|22000|km|abbr=on}} is believed to be the longest annual migration of any [[mammal]].<ref>{{Cite web |date=2022-10-18 |title=Map of the Gray Whale Migration - Baja Ecotours |url=https://www.bajaecotours.com/map-of-the-gray-whale-migration/ |access-date=2024-11-22 |language=en-US}}</ref> By mid-December to early January, the majority are usually found between [[Monterey, California|Monterey]] and [[San Diego, California|San Diego]] such as at [[Morro Bay State Marine Recreational Management Area and Morro Bay State Marine Reserve|Morro bay]], often visible from shore.<ref name=Swartz2018/> The [[whale watching]] industry provides [[ecotourism|ecotourists]] and [[marine mammal]] enthusiasts the opportunity to see groups of gray whales as they migrate.

By late December to early January, eastern grays begin to arrive in the calving lagoons and bays on the west coast of [[Baja California Sur]]. The three most popular are [[San Ignacio Lagoon|San Ignacio]], [[Magdalena Bay]] to the south, and, to the north, [[Laguna Ojo de Liebre]] (formerly known in English as Scammon's Lagoon after whaleman [[Charles Melville Scammon]], who discovered the lagoons in the 1850s and hunted the grays).<ref>{{cite web|title=Recovery of the Gray Whale|author=Davis, T.N.|url=http://www.gi.alaska.edu/ScienceForum/ASF3/339.html|publisher=Alaska Science Forum|date=1979-09-06|access-date=2009-01-25|archive-url=https://web.archive.org/web/20090212080641/http://www.gi.alaska.edu/ScienceForum/ASF3/339.html|archive-date=2009-02-12}}</ref><ref>{{Cite book|title=Baja Legends|author=Niemann, G.|pages=171–173|url=https://books.google.com/books?id=35WQOduN1F4C&pg=PA171|year=2002|publisher=Sunbelt Publications|isbn=0-932653-47-2}}</ref>

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.<ref>{{cite journal|last1=Findley|first1= T.L.|last2= Vidal|first2= O.|year= 2002|url=https://www.researchgate.net/publication/285118962|title= Gray whale (Eschrichtius robustus) at calving sites in the Gulf of California, México|journal= Journal of Cetacean Research and Management|volume =4|issue=1|pages=27–40}}</ref><ref>Mark Carwardine, 2019, 
Bloomsbury Publishing, Handbook of Whales, Dolphins and Porpoises, p.80</ref>

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.<ref>{{Cite web |last=Koontz |first=Kathi |date=2016-03-24 |title=Close Encounters With Baja's Gray Whales |url=https://www.oceanicsociety.org/trip-reports/close-encounters-with-bajas-gray-whales/ |access-date=2024-11-22 |website=Oceanic Society |language=en-US}}</ref>

By late March or early April, the returning animals can be seen from [[Puget Sound]] to Canada.

=====Resident groups=====
[[Image:Eschrichtius robustus Nootka 1.jpg|thumb|A gray whale swims near surf on [[Nootka Island]] 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.<ref>{{cite web|title=Demographic distinctness of the Pacific Coast Feeding Group of Gray Whales (''Eschrictius robustus'')|author=Lang, A.|url=http://swfsc.noaa.gov/textblock.aspx?Division=PRD&ParentMenuId=229&id=16955|publisher=NOAA Fisheries Service, Protected Resource Division, Southwest Fisheries Science Center|date=January 19, 2011|access-date=2011-02-25}}</ref>

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.<ref name=GrayArea /><ref name=hkd2005 /> Some of the better documented historical catches show that it was common for whales to stay for months in enclosed waters elsewhere, with known records in the [[Seto Inland Sea]]<ref name="shikoku-np.co.jp" /> and the Gulf of Tosa. Former feeding areas were once spread over large portions on mid-Honshu to northern Hokkaido, and at least whales were recorded for majority of annual seasons including wintering periods at least along east coasts of [[Korean Peninsula]] and [[Yamaguchi Prefecture]].<ref name=hkd2005 /> Some recent observations indicate that historic presences of resident whales are possible: a group of two or three were observed feeding in [[Izu Ōshima]] in 1994 for almost a month,<ref name=Nakamura12>{{cite web|author=Suitube|year=2012|title=中村宏治 コククジラ撮影秘話！|url=https://www.youtube.com/watch?v=YrUcUmQSufE| archive-url=https://ghostarchive.org/varchive/youtube/20211118/YrUcUmQSufE| archive-date=2021-11-18 | url-status=live|publisher=Japan Underwater Films|page=[[YouTube]]|access-date=2015-01-07}}{{cbignore}}</ref> 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.<ref>{{cite web|url=http://www.shikoku-np.co.jp/national/science_environmental/photo.aspx?id=20120417000459&no=1|title=コククジラが三河湾を回遊／絶滅恐れ、３月に１頭|work=四国新聞社|access-date=14 May 2015}}</ref><ref>{{cite web |url=http://1topi.jp/curator/Makoto_Ninomiya/1303/05/104995 |archive-url=https://web.archive.org/web/20140424094446/http://1topi.jp/curator/Makoto_Ninomiya/1303/05/104995 |archive-date=24 April 2014 |title=サービス終了のお知らせ |access-date=14 May 2015 }}</ref> One of the pair returned to the same coasts at the same time of the year in 2015 again.<ref name=Niigata2015 /> Reviewing on other cases on different locations among Japanese coasts and islands observed during 2015 indicate that spatial or seasonal residencies regardless of being temporal or permanental staying once occurred throughout many parts of Japan or on other coastal Asia.<ref name=2015Rematch />

====Western population====
[[File:GyeongjuGlyphs1.jpg|thumb|Gray and other whales were depicted on the [[Bangudae Petroglyphs]], indicating their historical presences along [[Korean Peninsula]].<ref>UNESCO World Heritage Centre, [https://whc.unesco.org/en/tentativelists/5486/ Daegokcheon Stream Petroglyphs]</ref>]]
[[Image:Sakhalin-gray-whale-small.jpg|thumb|A gray whale in the water off [[Sakhalin Island]].]]
The current western gray whale population summers in the [[Sea of Okhotsk]], mainly off [[Sakhalin-II|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.<ref name=Weller1999/><ref name=Vladimirov/> Its migration routes and wintering grounds are poorly known, the only recent information being from occasional records on both the eastern and western coasts of Japan<ref name=Kato/> and along the Chinese coast.<ref>Zhu, Q. (1998). "Strandings and sightings of the western Pacific stock of the gray whale ''Eschrichtius robustus'' in Chinese coastal waters. Paper SC/50lAS5 presented to the IWC Scientific Committee, April 1998, Oman</ref> Gray whale had not been observed on [[Commander Islands]] until 2016.<ref>[http://news.zapoved.ru/2016/05/31/krasnoknizhnyj-seryj-kit-priplyl-pod-okna-ofisa-zapovednika-komandorskij/ Краснокнижный серый кит приплыл под окна офиса заповедника «Командорский»] {{Webarchive|url=https://web.archive.org/web/20170312033503/http://news.zapoved.ru/2016/05/31/krasnoknizhnyj-seryj-kit-priplyl-pod-okna-ofisa-zapovednika-komandorskij/ |date=2017-03-12 }}. Retrieved on March 09, 2017</ref> The northwestern pacific population consists of approximately 300 individuals, based on photo identification collected off of Sakhalin Island and Kamchatka.<ref name="Fisheries"/>

The [[Sea of Japan]] was once thought not to have been a migration route, until several entanglements were recorded.<ref name=HKD2402>{{cite journal |title=New observations on Gray whales, ''Eschrichtius robustus'', from Central Japan, Sea of Japan |author=Nambu, Hisao |author2=Minowa, Kazuhiro |author3=Tokutake, Kouji |author4=Yamada, Tadasu K. |name-list-style=amp |journal=Japan Cetology |volume=24 |issue=24 |pages=11–14 |year=2014 |doi=10.5181/cetology.0.24_11 |doi-access=free }}</ref> Any records of the species had not been confirmed since after 1921 on [[Kyushu]].<ref name=hkd2005 /> However, there were numerous records of whales along the [[Genkai Sea]] off [[Yamaguchi Prefecture]],<ref>Uni Y. (2004) [http://www.h6.dion.ne.jp/~unisan/data/graywhale/cetaken15.html 西部系群コククジラ ''Eschrictius robustus'' の記録集成と通過海峡] {{Webarchive|url=https://web.archive.org/web/20150924024507/http://www.h6.dion.ne.jp/~unisan/data/graywhale/cetaken15.html |date=2015-09-24 }}. dion.ne.jp</ref> in Ine Bay in the [[Wakasa Wan Quasi-National Park|Gulf of Wakasa]], and in [[Tsushima Strait|Tsushima]]. Gray whales, along with other species such as right whales and [[Baird's beaked whale]]s, were common features off the north eastern coast of [[Hokkaido]] near [[Teshio, Hokkaido|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.<ref name=hkd2005 /> There are shallow, muddy areas favorable for feeding whales off [[Shiretoko Peninsula|Shiretoko]], such as at [[Shibetsu]], the [[Notsuke-Fūren Prefectural Natural Park|Notsuke Peninsula]], Cape Ochiishi on [[Nemuro Peninsula]], [[Mutsu Bay]],<ref name=geoc>{{cite web|url=http://www.geocities.jp/kayak_surfing/note/9.html|title=珍客コククジラ 静岡沖で潮吹き|publisher=geocities.jp|access-date=2014-05-09|archive-url=https://web.archive.org/web/20140512221641/http://www.geocities.jp/kayak_surfing/note/9.html|archive-date=2014-05-12}}</ref> 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<ref name=GrayArea /> and to near [[Hong Kong]]. Possibilities include [[Daya Bay]], [[Wailou]] Harbour on [[Leizhou Peninsula]], and possibly as far south as [[Hainan Province]] and [[Guangxi]], particularly around [[Hainan Island]]. These areas are at the southwestern end of the known range.<ref name="IUCN Western"/><ref name=Brownell/> It is unknown whether the whales' normal range once reached further south, to the [[Gulf of Tonkin]]. In addition, the existence of historical calving ground on [[Taiwan]] and [[Penghu|Penghu Islands]] (with some fossil records<ref>{{cite journal|doi=10.2517/2014PR009|title=Quaternary Fossil Gray Whales from Taiwan|journal=Paleontological Research|volume=18|issue=2|page=82|year=2014|last1=Tsai|first1=Cheng-Hsiu|last2=Fordyce|first2=R. Ewan|last3=Chang|first3=Chun-Hsiang|last4=Lin|first4=Liang-Kong|bibcode=2014PalRe..18...82T |s2cid=131250469|doi-access=free}}
</ref> and captures<ref>Brownell, R.L., Donovan, G.P., Kato, H., Larsen, F., Mattila, D., Reeves, R.R., Rock, Y., Vladimirov, V., Weller, D. & Zhu, Q. (2010) [https://portals.iucn.org/library/node/12737 Conservation Plan for Western North Pacific Gray Whales  (''Eschrichtius robustus'')]. IUCN</ref>), and any presence in other areas outside of the known ranges off [[Babuyan Islands]] in [[Philippines]] and coastal [[Vietnam]]ese 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.<ref>2014. [http://www.cesti.gov.vn/kh-cn-trong-nuoc/chuan-hoa-ten-ca-voi-xam-trong-bo-suu-tap-mau-vat-bao-tang-lich-su-quang-ninh.html Chuẩn hóa lại tên cá voi xám trong bộ sưu tập mẫu vật của bảo tàng lịch sử tỉnh Quảng Ninh] {{Webarchive|url=https://web.archive.org/web/20170312035151/http://www.cesti.gov.vn/kh-cn-trong-nuoc/chuan-hoa-ten-ca-voi-xam-trong-bo-suu-tap-mau-vat-bao-tang-lich-su-quang-ninh.html |date=2017-03-12 }}. Retrieved on March 09, 2017</ref><ref>2012. [http://grobest.com.vn/tin-tuc/44-tin-tuc/310-bi-an-nhung-con-ca-voi-khong-lo-dat-vao-bien-viet-nam.html Bí ẩn những con cá khổng lồ dạt vào biển Việt Nam] {{Webarchive|url=https://web.archive.org/web/20170312035203/http://grobest.com.vn/tin-tuc/44-tin-tuc/310-bi-an-nhung-con-ca-voi-khong-lo-dat-vao-bien-viet-nam.html |date=2017-03-12 }}. Retrieved on March 09, 2017</ref> Gray whales are known to occur in [[Taiwan Strait]] even in recent years.<ref name=Pingtan>What's on [[Xiamen]].[http://www.whatsonxiamen.com/tag-Pingtan+gray+whale.html Tags > Pingtan gray whale] {{Webarchive|url=https://web.archive.org/web/20170625015736/http://www.whatsonxiamen.com/tag-Pingtan+gray+whale.html |date=2017-06-25 }}. Retrieved on November 24. 2014</ref>

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 [[Jeju Province|Island of Jeju]], [[Haiyang]] Island, the Gulf of [[Shanghai]], or the [[Zhoushan Archipelago]].<ref>{{cite web|publisher=中华人民共和国濒危物种科学委员会 |title=濒危物种数据库 – 灰鲸 Eschrichtius robustus (Lilljeborg, 1861) |url=http://www.cites.org.cn/database/index.php?action=item&cid=26 |page=the [[CITES]] |access-date=2014-11-24 |archive-url=https://web.archive.org/web/20141225151532/http://www.cites.org.cn/database/index.php?action=item&cid=26 |archive-date=2014-12-25 }}</ref> There is no evidence of historical presence in Japan south of [[Ōsumi Peninsula]];<ref>Uni Y., 2010, 『コククジラは大隅海峡を通るのか?』, Japan Cetology Research Group News Letter 25, retrieved on 11-05-2014</ref> only one skeleton has been discovered in [[Miyazaki Prefecture]].<ref>{{cite web|url=http://svrsh1.kahaku.go.jp/marmam/?p=6|title=海棲哺乳類情報データベース|access-date=14 May 2015|archive-url=https://web.archive.org/web/20150903230215/http://svrsh1.kahaku.go.jp/marmam/?p=6|archive-date=3 September 2015}}</ref>  {{interlanguage link|Hideo Omura|jp|大村秀雄|vertical-align=sup}} 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.<ref name="shikoku-np.co.jp">{{cite web|url=http://www.shikoku-np.co.jp/feature/rensa/3/2/|title=連鎖の崩壊 第３部 命のふるさと ２−四国新聞社|access-date=14 May 2015}}</ref>

====Recent migration in Asian waters====
[[File:Gray Whale, Aogashima, March 11, 2017 by Aurora Chihiro.jpg|thumb|Gray whale at [[Aogashima]], [[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.<ref>{{cite web|author=Kim W.H., Sohn H.|author2=An Y-R.|author3=Park J.K.|author4=Kim N.D.|author5=Doo Hae An H.D.|year=2013|title=Report of Gray Whale Sighting Survey off Korean waters from 2003 to 2011|url=https://archive.iwc.int/?r=4795&k=a9d2de03fa|publisher=Cetacean Research Institute, [[National Fisheries Research & Development Institute]]|access-date=2014-05-18}}</ref> Prior to this, the last was of catches of 5 animals<ref name=GPR>[http://www.greenpeace.org/eastasia/Global/eastasia/publications/reports/oceans/Disappearing%20Whales%20-%20South%20Korea.PDF Disappearing Whales: Korea's Inconvenient Truth] {{Webarchive|url=https://web.archive.org/web/20160305210932/http://www.greenpeace.org/eastasia/Global/eastasia/publications/reports/oceans/Disappearing%20Whales%20-%20South%20Korea.PDF |date=2016-03-05 }}. Greenpeace (2012)</ref> off [[Ulsan]] in 1966.<ref name=GrayArea /> There was a possible sighting of a whale within the port of [[Samcheok]] in 2015.<ref>Hyun Woo Kim, Hawsun Sohn, Yasutaka Imai, 2018, [https://archive.iwc.int/pages/download.php?direct=1&noattach=true&ref=8847&ext=pdf&k= Possible occurrence of a Gray Whale off Korea in 2015], International Whaling Commission, SC/67B/CMP/11 Rev1</ref>

There had been 24 records along Chinese coasts including sighting, stranding, intended hunts, and bycatches since 1933.<ref name=2011insights>{{cite journal|doi=10.1578/AM.41.3.2015.327 |url=https://www.researchgate.net/publication/281442497 |title=Short Note: Insights from a Gray Whale (''Eschrichtius robustus'') Bycaught in the Taiwan Strait Off China in 2011|journal=Aquatic Mammals |volume=41 |issue=3 |page=327 |year=2015 |last1=Xianyan |first1=Wang |last2=Min |first2=Xu |last3=Fuxing |first3=Wu |last4=Weller |first4=David W. |last5=Xing |first5=Miao |last6=Lang |first6=Aimee R. |last7=Qian |first7=Zhu |bibcode=2015AqMam..41..327X }}</ref> The last report of occurrence of the species in Chinese waters was of a stranded semi adult female in the [[Bohai Sea]] in 1996,<ref name=GrayArea>{{cite web|url=https://www.researchgate.net/publication/275960466 |title=A Gray Area: On the Matter of Gray Whales in the Western North Pacific |date=2015-05-07 |access-date=2017-01-06}}</ref> and the only record in Chinese waters in the 21st century was of a fully-grown female being killed by entanglement in [[Pingtan County|Pingtan]], [[China]] in November, 2007.<ref name=Pingtan/> DNA studies indicated that this individual might have originated from the eastern population rather than the western.<ref name=2011insights />

Most notable observations of living whales after the 1980s were of 17 or 18 whales along [[Primorsky Krai]] in late October, 1989 (prior to this, a pair was reported swimming in the area in 1987), followed by the record of 14 whales in [[La Pérouse Strait]] on 13th, June in 1982 (in this strait, there was another sighting of a pair in October, 1987).<ref name=hkd2005>{{cite journal |url=http://hkd.a.la9.jp/jc/JC2005.pdf |title=Records of the western gray whale, ''Eschrichtius robustus'': its distribution and migration |journal=Japan Cetology |volume=20 |pages=21–29 |year=2010 |author=Nambu, Hisao |author2=Ishikawa, Hajime |author3=Yamada, Tadasu K. |name-list-style=amp |access-date=2015-10-15 |archive-url=https://web.archive.org/web/20160304040109/http://hkd.a.la9.jp/jc/JC2005.pdf |archive-date=2016-03-04 | issue=20 | doi=10.5181/cetology.0.20_21 }}</ref> In 2011, presences of gray whales were acoustically detected among pelagic waters in East China Sea between Chinese and Japanese waters.<ref>Gagnon, Chuck (November 2016) [https://www.iucn.org/sites/dev/files/wgwap_17-inf.6_iwc_66-cc29_wgw_observations_east_china_sea.pdf Western gray whale activity in the East China Sea from acoustic data: Memorandum for Dr. Brandon Southall] {{Webarchive|url=https://web.archive.org/web/20161224235107/https://www.iucn.org/sites/dev/files/wgwap_17-inf.6_iwc_66-cc29_wgw_observations_east_china_sea.pdf |date=2016-12-24 }}. iucn.org</ref>

Since the mid-1990s, almost all the confirmed records of living animals in Asian waters were from Japanese coasts.<ref>{{cite report|author=Kato H.|author2=Kishiro T.|author3=Bando T.|author4=Ohizumi H.|author5=Nakamura G.|author6=Okazoe N.|author7=Yoshida H.|author8= Mogoe T.|author9=Miyashita T.|url=https://archive.iwc.int/pages/search.php?search=!collection221&bc_from=themes|year=2015|title=Status Report of Conservation and Researches on the Western North Pacific Gray Whales in Japan, May 2014 – April 2015|journal=SC/66a/BRG|access-date=2016-02-23}}</ref> 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<ref name="Nakamura12"/> by several researchers and whale photographers.<ref>{{cite web|url=http://www.juf.co.jp/english/|title=Japan Underwater Films |access-date=14 May 2015}}</ref>
* 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 whale]]s, in 1997.<ref name=dbase>[https://web.archive.org/web/20160304060253/http://svrsh2.kahaku.go.jp/drift/FMPro?-db=rec2000web.fp5&-lay=hp&-format=%2Fdrift%2Fe%2Fdetail.htm&rec_id=19970722EX-032&-find Marine Mammals Stranding DataBase]. kahaku.go.jp</ref> 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.<ref name=geoc/>
* A sub-adult whale that stayed in the Ise and [[Mikawa Bay]] for nearly two months in 2012<ref>{{cite web |url=http://www.beachland.jp/beach_blog/post/e5889de8a898e98cb2efbc81e4b889e6b2b3e6b9bee381a6e382b3e382afe382afe382b7e383a9.aspx |title=footage |publisher=Beachland.jp |access-date=2017-01-06 |archive-date=2017-06-27 |archive-url=https://web.archive.org/web/20170627165031/http://www.beachland.jp/beach_blog/post/e5889de8a898e98cb2efbc81e4b889e6b2b3e6b9bee381a6e382b3e382afe382afe382b7e383a9.aspx }}</ref><ref>[http://www.beachland.jp/beach/study/pdf/18.pdf 2012 年に漂着した海棲哺乳類につい] {{Webarchive|url=https://web.archive.org/web/20140427223722/http://www.beachland.jp/beach/study/pdf/18.pdf |date=2014-04-27 }}. .beachland.jp</ref><ref>{{cite web |url=http://www.beachland.jp/beach_blog/post/e4bc8ae58ba2e6b9bee381a6e382afe382b7e383a9e799bae8a68befbc81efbc81.aspx |title=伊勢湾でクジラ発見！！ |publisher=Beachland.jp |access-date=2017-01-06 |archive-date=2017-06-27 |archive-url=https://web.archive.org/web/20170627171800/http://www.beachland.jp/beach_blog/post/e4bc8ae58ba2e6b9bee381a6e382afe382b7e383a9e799bae8a68befbc81efbc81.aspx }}</ref> was later confirmed to be the same individual as the small whale observed off [[Tahara, Aichi|Tahara]] near [[Cape Irago]] in 2010,<ref>{{cite web |url=http://www.beachland.jp/beach_blog/post/e2809ce38395e383aae383b3e5b195e2809de3818be38289e2809ce382b3e382afe382afe382b7e383a9e5b195e2809de381b8.aspx |title="プリン展"から"コククジラ展"へ |publisher=www.beachland.jp |access-date=2017-01-06 |archive-date=2017-06-27 |archive-url=https://web.archive.org/web/20170627150033/http://www.beachland.jp/beach_blog/post/e2809ce38395e383aae383b3e5b195e2809de3818be38289e2809ce382b3e382afe382afe382b7e383a9e5b195e2809de381b8.aspx }}</ref> 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),<ref name="shikoku-np.co.jp"/><ref name=dbase/> and is also the location where the first commercial whaling started. Other areas with several sighting or stranding records in recent years are off the Kumanonada Sea in [[Wakayama Prefecture|Wakayama]], off  [[Oshika Peninsula]] in [[Tōhoku]], and on coastlines close to [[Tomakomai]], [[Hokkaido]].
* Possibly the first confirmed record of living animals in Japanese waters in the Sea of Japan since the end of whaling occurred on 3 April 2014 at Nodumi Beach, [[Teradomari, Niigata]].<ref>{{cite web|author=Birdnetmaster|year=2015|title=2014年 日本海に出現したコククジラ / Grey whale 2014 Sea of Japan|url=https://www.youtube.com/watch?v=FS5b6Quo8hs| archive-url=https://ghostarchive.org/varchive/youtube/20211118/FS5b6Quo8hs| archive-date=2021-11-18 | url-status=live|publisher=[[YouTube]]|access-date=2015-10-14}}{{cbignore}}</ref><ref>{{Cite journal|author=Aoyagi A. |author2=Okuda J. |author3=Nambu H. |author4=Honma Y. |author5=Yamada K. T. |author6=Satou T. |author7=Ohta M. |author8=Ohara J. |author9=Imamura M. |title=2014年春に新潟県信濃川大河津分水路河口付近に出現したコククジラの観察 |journal=Japan Cetology |volume=24 |year=2014 |pages=15–22 |doi=10.5181/cetology.0.24_15 |doi-access=free }}</ref><ref>{{cite web|url=http://www.47news.jp/smp/localnews/toretate/2014/04/post_20140404142744.php|title=寺泊沖にクジラ現る・長岡 「生きたまま初めて見た」地元驚き|publisher=The 47News|access-date=14 May 2015}}</ref> Two individuals, measuring ten and five metres respectively, stayed near the mouth of [[Shinano River]] for three weeks.<ref name=SC65bBRG12/> It is unknown whether this was a cow-calf pair, which would have been a first record in Asia. All of the previous modern records in the Sea of Japan were of by-catches.<ref name=HKD2402 />
* One of the above pair returned on the same beaches at the same time of a year in 2015.<ref name=Niigata2015>{{cite web|year=2015 |title=Nearly extinct western gray whale sighted again in coastal waters off Niigata |url=http://newsonjapan.com/html/newsdesk/article/112273.php |archive-url=https://web.archive.org/web/20160304071001/http://newsonjapan.com/html/newsdesk/article/112273.php |archive-date=2016-03-04 |work=Asahi }}</ref><ref>{{cite news|author= Itou K.|year=2015|title=絶滅危惧のコククジラ、２年連続で現れた 新潟・長岡|url=http://www.asahi.com/articles/ASH4N5V61H4NUOHB01S.html|newspaper=The [[Asahi Shimbun]] |access-date=2015-10-13}}</ref>
*A juvenile or possibly or not with another larger individual remained in Japanese waters between January or March and May 2015.<ref>{{cite web|author=Takanawa N.|year=2015|title=【フォトギャラリー】伊豆諸島で見つかった希少なコククジラ|url=http://natgeo.nikkeibp.co.jp/atcl/web/15/360768/041600002/?ST=m_column|publisher=Japanese office of the [[National Geographic Society|National Geographic]]|access-date=2015-10-14}}</ref> 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.<ref>{{cite web|year=2015|title=コククジラ in 日本（超貴重）Western Gray Whale sightings (Extremely Rare!) |url=https://www.youtube.com/playlist?list=PLAILdeR3ZgA6mL0--dtsXHAALevCsK7kJ|publisher=[[YouTube]]|access-date=2015-10-14}}</ref> Possibly the same individual was seen off Futo as well.<ref name=oceana>{{cite web|url=https://oceana.ne.jp/domestic/59265 |title=ダイビング中にコククジラと遭遇のミラクル！ ～房総半島・西川名と伊豆半島・赤沢で相次ぐ～ ｜ オーシャナ |publisher=Oceana.ne.jp |date=2016-01-19 |access-date=2017-01-06}}</ref> This later was identified as the same individual previously recorded on Sakhalin in 2014, the first re-recording one individual at different Asian locations.<ref name=2015Rematch>{{cite conference|last1=Weller|first1=D. W.|last2=Takanawa|first2=N.|first3=H.|last3=Ohizumi|first4=N.|last4=Funahashi|first5=O. A.|last5=Sychenko|first6=A. M.|last6= Burdin|first7=A. R.|last7=Lang|first8=R. L.|last8=Brownell Jr.|year=2015|url=https://archive.iwc.int/pages/search.php?search=!collection221&bc_from=themes|title=Photographic match of a western gray whale between Sakhalin Island, Russia, and the Pacific Coast of Japan. Paper SC/66a/BRG/17|book-title=International Whaling Commission, Scientific Committee (SC66a meeting)|location=San Diego, USA}}</ref>
* A young whale was observed by land-based fishermen at Cape Irago in March, 2015.<ref>{{cite web|url=https://www.facebook.com/ryo.okamoto.902/videos/744000622363775/ |title=Ryo Okamoto – 伊良湖岬で釣りしてたら、クジラ出現。... |publisher=Facebook |date=2015-03-23 |access-date=2017-01-06}}</ref>
* One of the above pair appeared in 2015 off southeastern Japan and then reappeared off [[Tateyama, Chiba|Tateyama]] in January, 2016.<ref>{{cite web|url=https://www.youtube.com/watch?v=7ei7s8Rfqa8 | archive-url=https://ghostarchive.org/varchive/youtube/20211118/7ei7s8Rfqa8| archive-date=2021-11-18 | url-status=live|title=今日のコククジラ 館山 西川名 201601f |publisher=YouTube |date=2016-01-09 |access-date=2017-01-06}}{{cbignore}}</ref> The identity of this whale was confirmed by Nana Takanawa who photographed the same whale on Niijima in 2015.<ref>Braulik, Gill (2015-04-16) [https://web.archive.org/web/20160123234348/https://www.iucn-csg.org/index.php/2015/04/16/1940/ Young Gray Whale Sighted near Tokyo Islands]. IUCN SSC – Cetacean Specialist Group</ref> Likely the same individual was sighted off Futo<ref name=oceana /> and half an hour later off Akazawa beach in [[Itō, Shizuoka]] on the 14th.<ref>{{cite web|url=https://www.youtube.com/watch?v=ML7xk3FXosQ | archive-url=https://ghostarchive.org/varchive/youtube/20211118/ML7xk3FXosQ| archive-date=2021-11-18 | url-status=live|title=赤沢 コククジラ 2016.1.14 | date=10 March 2016|publisher=YouTube |access-date=2017-01-06}}{{cbignore}}</ref><ref>{{cite web|url=http://www.ds-mieux.com/?p=19346 |title=伊豆のダイビングサービス &#124; ダイビングサービス mieux -みう- &#124; クジラが～！！ |date=14 January 2016 |publisher=Ds-mieux.com |access-date=2017-01-06}}</ref><ref>{{cite web|url=https://www.facebook.com/ds.mieux/videos/1695723133979427/?fref=nf |title=動画っす(｀_´)ゞ – ダイビングサービス mieux – みう |publisher=Facebook |date=2016-01-13 |access-date=2017-01-06}}</ref> 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 {{convert|9|m|ft}} was beached nearby [[Wadaura Station|Wadaura]] on March 4, 2016.<ref>[https://web.archive.org/web/20160305073024/http://www3.nhk.or.jp/news/html/20160305/k10010432701000.html 絶滅心配 コククジラの死骸 千葉・南房総で見つかる]. nhk.or.jp (2015-05-03)</ref> Investigations on the corpse indicate that this was likely a different individual from the above animal.
* A {{convert|7|m|ft}} carcass of young female was firstly reported floating along [[Atami]] on 4 April then was washed ashore on [[Itō, Shizuoka|Ito]] on the 6th.<ref>{{Cite web|url=https://digital.izu-np.co.jp/|archive-url=https://web.archive.org/web/20160420005528/http://izu-np.co.jp/ito/news/20160407iz0000000007000c.html|title=伊豆新聞デジタル – IZU SHIMBUN DIGITAL --|archive-date=April 20, 2016|website=伊豆新聞デジタル}}</ref>
* 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]].<ref>{{Cite web |last=日本テレビ |title=東京湾で目撃相次ぐクジラ カメラが捉えた｜日テレNEWS NNN |url=https://news.ntv.co.jp/category/society/359324 |access-date=2024-11-22 |website=日テレNEWS NNN |language=ja-JP}}</ref><ref>{{Cite AV media |url=https://www.youtube.com/watch?v=9v7b02cCsP0 |title=ゴムボート東京湾ホエールウォッチング❗ |date=2017-03-26 |last=鎌倉ゴムボートコング山田肇 |access-date=2024-11-22 |via=YouTube}}</ref> 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.<ref>[[:ja:みんなのニュース|みんなのニュース]]. 2017. [http://www.fnn-news.com/news/headlines/articles/CONN00356017.html 撮影成功! 姿現した「東京湾クジラ」] {{Webarchive|url=https://web.archive.org/web/20170422211841/http://www.fnn-news.com/news/headlines/articles/CONN00356017.html |date=2017-04-22 }}. The [[Fuji News Network]] Retrieved on April 22, 2017</ref>

==Whaling==

===North Pacific===
[[File:Eschrichtius robustus1.jpg|thumb|[[Charles Melville Scammon]]'s 1874 illustration of a gray whale]]

====Eastern population====
Humans and [[orca]]s are the adult gray whale's only predators, although orcas are the more prominent predator.<ref>{{cite web|url=http://marinebio.org/species.asp?id=279|title=Gray Whales, Eschrichtius robustus|website=MarineBio.org|access-date=2018-12-13|archive-url=https://web.archive.org/web/20181215222445/http://marinebio.org/species.asp?id=279|archive-date=2018-12-15}}</ref> The carcass of a {{convert|14|m|ft|abbr=on}} long adult female Gray whale, believed to have been eaten by an orca, was once found.<ref>{{cite journal |last1=Gallo-Reynoso |first1=Juan-Pablo |last2=Barba-Acuña |first2=Isai-David |last3=Guerrero-Ruiz |first3=Mercedes-Eugenia |last4=Mellink |first4=Eric |last5=Egido-Villarreal |first5=Janitzio |last6=Flores-Morán |first6=Adriana-Estefanía |last7=Pérez-Puig |first7=Hector |title=Killer whales (Orcinus orca) predation on mysticetes in the Gulf of California, Mexico |journal=Latin American Journal of Aquatic Mammals |date=October 2025 |volume=20 |article-number=2 |doi=10.5597/lajam00360 |s2cid=282729857 |url=https://www.researchgate.net/publication/397131492 |doi-access=free }}</ref> Aboriginal hunters, including those on [[Vancouver Island]] and the [[Makah people|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."<ref name=Henderson1972>{{cite book
  | last = Henderson
  | first = David A.
  | title = Men & Whales at Scammon's Lagoon
  | publisher = Dawson's Book Shop
  | year = 1972
  | location = Los Angeles
}}{{clarify|reason="Dawson's Book Shop" is not a publisher but is a book seller; state the publisher;|date=March 2022}}</ref>

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, California|Crescent City]] in northern California south to San Ignacio Lagoon. During the same period, vessels targeting [[North Pacific right whale|right]] and [[bowhead whale]]s 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.<ref name=Henderson1972/>

In December 1857, Charles Scammon, in the brig ''Boston'', along with his schooner-tender ''Marin'', entered Laguna Ojo de Liebre (Jack-Rabbit Spring Lagoon) or later known as Scammon's Lagoon (by 1860) and found one of the gray's last refuges. He caught 20 whales.<ref name=Henderson1972/> He returned the following winter (1858–59) with the bark ''Ocean Bird'' and schooner tenders ''A.M. Simpson'' and ''Kate''. In three months, he caught 47 cows, yielding {{convert|1700|oilbbl}} of oil.<ref name=Henderson1970>{{cite book
  | last = Scammon
  | first = Charles Melville |author2=David A. Henderson
  | title = Journal aboard the bark Ocean Bird on a whaling voyage to Scammon's Lagoon, winter of 1858–59
  | publisher = Dawson's Book Shop
  | year = 1972
  | location = Los Angeles
}}{{clarify|reason="Dawson's Book Shop" is not a publisher but is a book seller; state the publisher;|date=March 2022}}</ref> 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.<ref name=Henderson1972/>

Between 1846 and 1874, an estimated 8,000 gray whales were killed by American and European whalemen, with over half having been killed in the Magdalena Bay complex (Estero Santo Domingo, Magdalena Bay itself, and Almejas Bay) and by shore whalemen in California and Baja California.<ref name=Henderson1972/>
[[File:Gray Whale Spyhopping courtesy of Marc Webber USFWS.jpg|thumb|Spyhopping off the Alaskan coast]]
A second, shorter, and less intensive hunt occurred for gray whales in the eastern North Pacific. Only a few were caught from two whaling stations on the coast of California from 1919 to 1926, and a single station in Washington (1911–21) accounted for the capture of another. For the entire west coast of North America for the years 1919 to 1929, 234 gray whales were caught. Only a dozen or so were taken by British Columbian stations, nearly all of them in 1953 at [[Coal Harbour, British Columbia|Coal Harbour]].<ref>{{cite book |last=Tønnessen |first=Johan |author2=Arne Odd Johnsen |author2-link=Arne Odd Johnsen  |title=The History of Modern Whaling |year=1982 |publisher=University of California Press, Berkeley |isbn=0-520-03973-4 }}</ref> 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.<ref>Brownell Jr., R. L. and Swartz, S. L. 2006. The floating factory ship California operations in Californian waters, 1932–1937. ''International Whaling Commission'', ''Scientific Committee''.</ref>

====Western population====
The Japanese began to catch gray whales beginning in the 1570s. At Kawajiri, [[Nagato Province|Nagato]], 169 gray whales were caught between 1698 and 1889. At [[Tsuro, Japan|Tsuro]], [[Shikoku]], 201 were taken between 1849 and 1896.<ref>Kasuya, T. (2002). "Japanese whaling", in ''Encyclopedia of Marine Mammals''. W. F. Perrin, B. Wursig, and J.G.M. Thewissen, eds. San Diego: Academic Press, pp. 655–662, {{ISBN|978-0-12-373553-9}}.</ref> Several hundred more were probably caught by American and European whalemen in the [[Sea of Okhotsk]] from the 1840s to the early 20th century.<ref name="Weller, D. et al 2002">{{cite journal|title=The western gray whale: a review of past exploitation, current status and potential threats |author=David W. Weller |author2=Alexander M. Burdin |author3=Bernd Würsig |author4=Barbara L. Taylor |author5=Robert L. Brownell Jr|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1084&context=usdeptcommercepub|journal=Journal of Cetacean Research and Management |volume= 4|issue=1|pages=7–12|year=2002|display-authors=etal|via=University of Nebraska - Lincoln}}</ref> 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.<ref name="Weller, D. et al 2002"/>

As of 2001, the Californian gray whale population had grown to about 26,000. As of 2016, the population of western Pacific (seas near Korea, Japan, and [[Kamchatka]]) gray whales was an estimated 200.<ref name="fisheries.noaa.gov"/>

===North Atlantic===
The North Atlantic population may have been hunted to extinction in the 18th century. Circumstantial evidence indicates whaling could have contributed to this population's decline, as the increase in whaling activity in the 17th and 18th centuries coincided with the population's disappearance.<ref name="sbjhnc"/> A. B. Van Deinse points out the "scrag whale", described by P. Dudley in 1725, as one target of early New England whalers, was almost certainly the gray whale.<ref name="Van Deinse 1937 161–188"/><ref name="Dudley 1725 256–259"/> In his 1835 history of [[Nantucket Island]], Obed Macy wrote that in the early pre-1672 colony, a whale of the kind called "scragg" entered the harbor and was pursued and killed by the settlers.<ref name="Macy O 1835"/> Gray whales (Icelandic ''sandlægja'') were described in Iceland in the early 17th century.<ref>Jón Guðmundsson lærði (1966). ''Ein stutt udirrietting um Íslands adskiljanlegu náttúrur''. ed. Halldór Hermannsson, Cornell University Library, Ithaca, New York.</ref> 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.<ref name="van den Hurk-2025" /> Formations of commercial whaling among the Mediterranean basin(s) have been considered to be feasible as well.<ref name=SpeciesMatters/>

==Conservation==
[[Image:Gray whale, theb3672.jpg|thumb|Joint American-Russian freeing effort of whales entrapped by ice floe in Beaufort Sea as part of [[Operation Breakthrough]].]]
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 [[Chukchi Peninsula|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 Union|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.<ref>{{Cite web |title=Russian Federation |url=https://iwc.int/russian-federation |access-date=2024-11-22 |website=iwc.int |language=en}}</ref>

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 people|Makah]] tribe of [[Washington (state)|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.<ref>{{Cite news|url=http://seattletimes.nwsource.com/html/localnews/2003876011_whale09m.html |work=The Seattle Times |title=Gray whale shot, killed in rogue tribal hunt |first1=Lynda V. |last1=Mapes |first2=Keith |last2=Ervin |date=2007-09-09 |archive-url=https://web.archive.org/web/20111125234530/http://seattletimes.nwsource.com/html/localnews/2003876011_whale09m.html |archive-date=2011-11-25 }}</ref>
[[File:Cordell Bank National Marine Sanctuary school class spots gray whale 2016.png|thumb|left|A school class in [[California]] spots a gray whale in the [[Cordell Bank National Marine Sanctuary]] during a field trip  for the Every Kid in a Park program in&nbsp;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''.<ref name="iucn status 19 November 2021" /> The northwest Pacific population is also listed as endangered by the U.S. government's [[National Marine Fisheries Service]] under the U.S. [[Endangered Species Act]]. The IWC Bowhead, Right and Gray Whale subcommittee in 2011 reiterated the conservation risk to western gray whales is large because of the small size of the population and the potential anthropogenic impacts.<ref name="iwcoffice.org"/>

Gray whale migrations off of the Pacific Coast were observed, initially, by Marineland of the Pacific in Palos Verdes, California. The Gray Whale Census, an official gray whale migration census that has been recording data on the migration of the Pacific gray whale has been keeping track of the population of the Pacific gray whale since 1985. This census is the longest running census of the Pacific gray whale. Census keepers volunteer from December 1 through May, from sun up to sun down, seven days a week, keeping track of the number of gray whales migrating through the area off of Los Angeles. Information from this census is listed through the American Cetacean Society of Los Angeles (ACSLA).

South Korea and China list gray whales as protected species of high concern. In South Korea, the {{interlanguage link|Gray Whale Migration Site|ko|울산 귀신고래 회유해면|vertical-align=sup}}<ref>{{cite web|url=http://www.cha.go.kr/korea/heritage/search/Culresult_Db_View.jsp?mc=NS_04_03_01&VdkVgwKey=16,01260000,ZZ | title=- 문화재검색결과 상세보기 – 문화재검색|access-date=14 May 2015}}</ref> was registered as the 126th [[Natural monuments of South Korea|national monument]] in 1962,<ref>{{cite web|url=http://english.visitkorea.or.kr/enu/SI/SI_EN_3_1_1_1.jsp?cid=1751673 |title=Gray Whale Migration Site (울산 귀신고래 회유해면) |publisher=Official Korea Tourism Organization}}</ref> although illegal hunts have taken place thereafter,<ref name=GPR /> and there have been no recent sightings of the species in Korean waters.

===Rewilding proposal===
In 2005, two conservation biologists proposed a plan to airlift 50 gray whales from the Pacific Ocean to the Atlantic Ocean. They reasoned that, as Californian gray whales had replenished to a suitable population, surplus whales could be transported to [[Species reintroduction|repopulate]] the extinct British population.<ref name="2005-airlift-NewScientist">{{cite magazine |url=https://www.newscientist.com/article/mg18725094.200-moving-whales-across-the-world.html |title=Moving Whales Across the World |magazine=New Scientist |author=Hooper, Rowan |date=23 July 2005 |access-date=22 August 2013}}</ref><ref name="2005-airlift-BBC">{{cite news |url=https://news.bbc.co.uk/2/hi/uk_news/england/cumbria/4692193.stm |title=US whales may be brought to UK |work=BBC News |author=Hooper, Rowan |date=18 July 2005 |access-date=22 August 2013}}</ref> {{As of|2024}} this plan has not been undertaken.<ref name="Monbiot-Feral">{{cite book | title=Feral: Searching for Enchantment on the Frontiers of Rewilding| author=Monbiot, George | publisher=Allen Lane | year=2013 | isbn=978-1-846-14748-7 }}</ref>

==Threats==
According to the Government of Canada's Management Plan for gray whales, threats to the eastern North Pacific population of gray whales include:<ref>[http://www.dfo-mpo.gc.ca/species-especes/species-especes/greyWhale-NP-baleine-grise-PN-eng.htm The Grey Whale (Eastern North Pacific Population)] {{webarchive |url=https://web.archive.org/web/20160114181406/http://www.dfo-mpo.gc.ca/species-especes/species-especes/greyWhale-NP-baleine-grise-PN-eng.htm |date=January 14, 2016 }}. Species at Risk. dfo-mpo.gc.ca</ref> increased human activities in their breeding lagoons in Mexico, [[climate change]], [[marine mammals and sonar|acute noise]], toxic spills, aboriginal whaling, [[bycatch|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.<ref name="iwcoffice.org"/> The substantial nearshore industrialization and shipping congestion throughout the migratory corridors of the western gray whale population represent potential threats by increasing the likelihood of exposure to ship strikes, chemical pollution, and general disturbance.<ref name="IUCN Western"/><ref name="Weller, D. et al 2002"/>

Offshore gas and oil development in the Okhotsk Sea within {{convert|20|km|mi|abbr=on}} of the primary feeding ground off [[Sakhalin-II#Plans for Piltun-Astokhskoye-C platform|northeast Sakhalin Island]] is of particular concern. Activities related to oil and gas exploration, including geophysical seismic surveying, pipelaying and drilling operations, increased vessel traffic, and oil spills, all pose potential threats to western gray whales. Disturbance from underwater industrial noise may displace whales from critical feeding habitat. Physical habitat damage from drilling and dredging operations, combined with possible impacts of oil and chemical spills on benthic prey communities also warrants concern. The western gray whale population is considered to be endangered according to IUCN standards.<ref name="IUCN Western"/><ref name=Reeves/>

Along Japanese coasts, four females including a cow-calf pair were trapped and killed in nets in the 2000s. There had been a record of dead whale thought to be harpooned by dolphin-hunters found on [[Hokkaido]] in the 1990s.<ref name="IUCN Western"/><ref>{{cite web|author=Yamada T.|author2=Watanabe Y.|title=Marine Mammals Stranding DataBase – Gray Whale|url=http://svrsh2.kahaku.go.jp/drift/FMPro?-db=rec2000web.fp5&-lay=hp&-format=/drift/e/detail.htm&rec_id=19960516M-088&-find|publisher=The [[National Museum of Nature and Science]]|access-date=2015-01-13|archive-url=https://web.archive.org/web/20140512215922/http://svrsh2.kahaku.go.jp/drift/FMPro?-db=rec2000web.fp5&-lay=hp&-format=%2Fdrift%2Fe%2Fdetail.htm&rec_id=19960516M-088&-find|archive-date=2014-05-12}}</ref> Meats for sale were also discovered in Japanese markets as well.<ref>{{cite journal|doi=10.1111/j.1748-7692.2002.tb01036.x|title=Gray Whale Products Sold in Commercial Markets Along the Pacific Coast of Japan|journal=Marine Mammal Science|volume=18|page=295|year=2002|last1=Baker|first1=C. S.|last2=Dalebout|first2=M. L.|last3=Lento|first3=G. M.|last4=Funahashi|first4=Naoko|issue=1 |bibcode=2002MMamS..18..295B }}</ref>

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.<ref>{{Cite web |last= |first= |date=2024-11-04 |title=2019-2023 Eastern North Pacific Gray Whale UME (CLOSED) {{!}} NOAA Fisheries |url=https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2023-eastern-north-pacific-gray-whale-ume-closed |access-date=2024-11-22 |website=NOAA |language=en}}</ref> 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.<ref>{{Cite web |last=Daley |first=Jason |title=NOAA Is Investigating 70 Gray Whale Deaths Along the West Coast |url=https://www.smithsonianmag.com/smart-news/noaa-investigating-dozens-gray-whale-deaths-along-west-coast-180972333/ |access-date=2024-11-22 |website=Smithsonian Magazine |language=en}}</ref>

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.<ref>{{Cite web |last=Hickok |first=Kimberly |date=2020-01-10 |title=Solar Storms Might Be Causing Gray Whales to Get Lost |url=https://www.livescience.com/solar-storms-and-gray-whale-strandings.html |access-date=2024-11-22 |website=livescience.com |language=en}}</ref> This may apply to the other species of cetaceans, such as sperm whales.<ref>{{cite journal |last1=Vanselow |first1=Klaus Heinrich |last2=Jacobsen |first2=Sven |last3=Hall |first3=Chris |last4=Garthe |first4=Stefan |title=Solar storms may trigger sperm whale strandings: explanation approaches for multiple strandings in the North Sea in 2016 |journal=International Journal of Astrobiology |date=15 August 2017 |volume=17 |issue=4 |pages=336–344 |doi=10.1017/s147355041700026x |doi-access=free |hdl=10037/24936 |hdl-access=free }}</ref> 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."<ref name="BANG">{{cite news| title=Unusual Number of Killer Whales Sighted |page=B1 |author=Andrew Lachman |publisher=Bay Area News Group | work=San Jose Mercury-News |date=May 8, 2018}}</ref> 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.<ref name="BANG" /> Orcas will often arrive in Monterey Bay to intercept gray whales during their northbound migration, targeting females migrating with newborn calves. They will separate the calf from the mother and hold the calf under water to drown it. The tactic of holding whales under water to drown them is certainly used by orcas on adult gray whales as well.<ref>{{cite web| url = https://www.youtube.com/watch?v=TmO0wiK5DqI| title = Deadly Killer Whale Moments (BBC Earth)| website = [[YouTube]]| date = 23 March 2021}}</ref> It is roughly estimated that 33% of the gray whales born in a given year might be killed by predation.<ref>{{cite journal |last1=Morell |first1=V. |title=Killer Whales Earn Their Name |journal=Science |date=20 January 2011 |volume=331 |issue=6015 |pages=274–276 |doi=10.1126/science.331.6015.274 |pmid=21252323 |bibcode=2011Sci...331..274M }}</ref>

==Captivity==
[[Image:Graywhale MMC.jpg|thumb|A gray whale in 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.<ref>{{cite journal|last1=Hubbs|first1=Carl L. |last2=Evans| first2=William E. |year=1974|title=The California gray whale: papers presented at the California Gray Whale Workshop, Scripps Institution of Oceanography|url=https://archive.org/stream/californiagraywh00sout/californiagraywh00sout_djvu.txt|journal=Marine Fisheries Review|volume=36|number=4}}</ref> 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.<ref>{{cite journal|url= http://www.aquaticmammalsjournal.org/share/AquaticMammalsIssueArchives/2001/AquaticMammals_27-03/27-03_Goff.pdf |archive-url=https://web.archive.org/web/20151015214719/http://www.aquaticmammalsjournal.org/share/AquaticMammalsIssueArchives/2001/AquaticMammals_27-03/27-03_Goff.pdf |archive-date=2015-10-15 |url-status=live|first1=J. L. |last1=Sumich|first2=T.|last2=Goff|first3=W.|last3=L. Perryman|year=2001|title=Growth of two captive gray whale calves|journal=Aquatic Mammals|volume=27|issue=3|pages=231–233}}</ref> 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 {{convert|19,200|lbs|kg}} and {{convert|31|ft|m}} when she was released, J.J. was the largest marine mammal ever to be kept in captivity.<ref>{{cite newsgroup|url=https://www.latimes.com/archives/la-xpm-1998-apr-01-mn-34942-story.html|first=Tony|last=Perry|year= 1998|title=Rescued Whale J.J. Begins Long Journey Home|newspaper=Los Angeles Times|access-date=29 January 2016}}</ref>

==See also==
*[[Gray Whale Cove State Beach]]
*[[Gray Whale Ranch]]
*[[List of cetaceans]]
*''[[Cryptolepas rhachianecti]]'' (barnacle that lives on gray whales)

==References==
{{Reflist|refs=
<ref name=Brownell>{{cite journal|author1=Brownell, R.L. Jr.  |author2=Chun, C.|year= 1977|title= Probable existence of the Korean stock of the gray whale (''Eschrichtius robustus'')|jstor=1379584|journal=J. Mammal.|volume=58|issue=2|pages=237–9|doi=10.2307/1379584 |bibcode=1977JMamm..58..237B }}</ref>

<ref name=Kato>Kato, H., Ishikawa, H., Bando, T., Mogoe, T. and Moronuki, H. (2006). Status Report of Conservation and Researches on the Western Gray Whales in Japan, June 2005 – May 2006. Paper SC/58/O14 presented to the IWC Scientific Committee, June 2006</ref>

<ref name=Reeves>Reeves, R.R., Brownell Jr., R.L., Burdin, A., Cooke, J.G., Darling, J.D., Donovan, G.P., Gulland, F.M.D., Moore, S.E., Nowacek, D.P., Ragen, T.J., Steiner, R.G., Van Blaricom, G.R., Vedenev, A. and Yablokov, A.V. (2005). [https://www.iucn.org/sites/dev/files/isrp_report_with_covers_high_res.pdf Report of the Independent Scientific review Panel on the Impacts of Sakhalin II Phase 2 on Western Pacific Gray Whales and Related Biodiversity]. IUCN, Gland Switzerland, and Cambridge, U.K.</ref>

<ref name=Vladimirov>{{cite journal|author=Vladimirov, V.L.|year=1994|title= Recent distribution and abundance level of whales in Russian Far-Eastern seas|journal= Russian J. Mar. Biol. |volume=20|pages=l–9}}</ref>

<ref name=Weller1999>{{cite journal|author=Weller, D.W.|author2=Wursig, B.|author3=Bradford, A.L.|author4=Burdin, A.M.|author5=Blokhin, S.A.|author6=inakuchi, H.|author7=Brownell, R.L. Jr.|name-list-style=amp|year=1999|title=Gray whales (''Eschrichtius robustus'') off Sakhalin Island, Russia: seasonal and annual patterns of occurrence|journal=Mar. Mammal Sci.|volume=15|issue=4|pages=1208–27|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1097&context=usdeptcommercepub|doi=10.1111/j.1748-7692.1999.tb00886.x|bibcode=1999MMamS..15.1208W |url-access=subscription}}</ref>
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  | title     = Nachrichten von Island, Grönland und der Strasse Davis
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  | publisher = Verlegts Georg Christian Grund, Buckdr.
  | location  = Hamburg
  | url       = https://archive.org/stream/herrnjohannander00ande#page/200/mode/2up 
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}}
* {{Cite book
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  | last2     = McLeod
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  | chapter   = The Fossil Record and Phyletic Relationships of Gray Whales
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  | title     = The Gray Whale: ''Eschrichtius Robustus''
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}}
**{{cite web |title=''Eschrichtius Gray'' 1864 (gray whale) |website=Fossilworks |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=36714 |access-date=2021-12-17 |archive-date=2022-08-18 |archive-url=https://web.archive.org/web/20220818013138/http://www.fossilworks.org/cgi-bin/bridge.pl?action=taxonInfo&taxon_no=36714 |url-status=live }}
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**{{cite web |title=P. J. Van Beneden and P. Gervais 1868 |website=Fossilworks |url=https://paleobiodb.org/classic/displayRefResults?reference_no=13984 |access-date=2021-12-17 |archive-date=2021-08-21 |archive-url=https://web.archive.org/web/20210821134135/http://fossilworks.org/cgi-bin/bridge.pl?a=displayReference&reference_no=13984 |url-status=live }}

==Further reading==
*{{cite book |title=The Gray whale: Eschrichtius robustus |first1=Mary Lou |last1=Jones |first2=Steven L. |last2=Swartz |first3=Stephen |last3=Leatherwood |page=600 |publisher=Academic Press |year=1984 |isbn=978-0-12-389180-8 }}
*{{cite book |title=The Life History and Ecology of the Gray Whale: Eschrichtius Robustus, Special Publication No. 3 |first1= Dale W. |last1=Rice |first2=Allen A. |last2=Wolman |publisher=The American Society of Mammalogists |date=April 30, 1971 |page=152 }}
*{{cite magazine|title=Gray Whales|first1=Steven L.|last1=Swartz|first2=Mary Lou|last2=Jones|magazine=[[National Geographic (magazine)|National Geographic]]|pages=754–771|volume=171|issue=6|date=June 1987|issn=0027-9358|oclc=643483454}}
*{{cite book |title=E. robustus: The biology and human history of gray whales |first1=James|last1=Sumich |publisher=Whale Cove Marine Education |edition=1st |year=2014 |page=199 |isbn=978-0-692-22542-4 }}

==External links==
{{Commons category|Eschrichtius_robustus|Gray whale}}
{{Wikispecies|Eschrichtius_robustus|Gray whale}}
* [http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/graywhale.htm US National Marine Fisheries Service Gray Whale web page]
* {{cite iucn |author=Cooke, J.G. |year=2018 |title=''Eschrichtius robustus'' |volume=2018 |article-number=e.T8097A50353881 |doi=10.2305/IUCN.UK.2018-2.RLTS.T8097A50353881.en |access-date=2 April 2024}}
* [https://web.archive.org/web/20090609205523/http://www.arkive.org/gray-whale/eschrichtius-robustus/ Arkive – images & video of gray whale]
* [http://swfsc.noaa.gov/uploadedFiles/Divisions/PRD/Programs/Photogrammetry/FINAL%20-%20GRAY%20WHALE%20SPECIES%20ACCOUNT%20Weller%20Aug%202010-1.pdf?n=560 Society for Marine Mammalogy – Gray Whale Species Account]
* {{Internet Archive short film|id=gov.ntis.ava01336vnb1|name=The California Gray Whale}}
* [http://cetus.ucsd.edu/voicesinthesea_org/species/baleenWhales/gray.html Voices in the Sea – Sounds of the Gray Whale] {{Webarchive|url=https://web.archive.org/web/20150109231904/http://cetus.ucsd.edu/voicesinthesea_org/species/baleenWhales/gray.html |date=2015-01-09 }}

{{Cetacea|M.}}
{{Portal bar|Cetaceans|Mammals|Animals|Biology|Marine life|Oceans}}
{{Taxonbar |from=Q179154}}
{{Authority control}}

[[Category:Mammals described in 1861]]
[[Category:Taxa named by Wilhelm Lilljeborg]]
[[Category:Gray whales]]
[[Category:Eschrichtiidae]]
[[Category:Cetaceans of the Pacific Ocean]]
[[Category:Cetaceans of the Arctic Ocean]]
[[Category:Extant Late Pleistocene first appearances]]
[[Category:Symbols of California]]
[[Category:Biota of the Temperate Northern Pacific]]