Editing Porpoise (section)

==Interactions with humans==

===Research history===
{{See also|Cryptid whale|Whale#In myth, literature and art}}
{{Quote box|width=30%|align=right|quote=The tube in the head, through which this kind fish takes its breath and spitting water, located in front of the brain and ends outwardly in a simple hole, but inside it is divided by a downward bony septum, as if it were two nostrils; but underneath it opens up again in the mouth in a void.|source=–John Ray, 1671, the earliest description of cetacean airways}}

In [[Aristotle]]'s time, the 4th century BCE, porpoises were regarded as fish due to their superficial similarity. Aristotle, however, could already see many physiological and anatomical similarities with the terrestrial vertebrates, such as blood (circulation), lungs, uterus and fin anatomy.{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}}  His detailed descriptions were assimilated by the Romans, but mixed with a more accurate knowledge of the dolphins, as mentioned by [[Pliny the Elder]] in his "Natural history". In the art of this and subsequent periods, porpoises are portrayed with a long snout (typical of dolphins) and a high-arched head. The [[harbour porpoise]] was one of the most accessible species for early [[cetology|cetologists]], because it could be seen very close to land, inhabiting shallow coastal areas of Europe. Much of the findings that apply to all cetaceans were first discovered in porpoises.<ref>{{cite book|author= Conrad Gesner|url=http://etext.lib.virginia.edu/toc/modeng/public/AriHian.html|title=Historiae animalium |date=6 September 2008 |archive-url= https://web.archive.org/web/20080906090248/http://etext.lib.virginia.edu/toc/modeng/public/AriHian.html |archive-date=6 September 2008 |access-date=4 September 2015}}</ref> One of the first anatomical descriptions of the airways of the whales on the basis of a harbor porpoise dates from 1671 by John Ray.<ref>{{cite journal|author=J. Ray|title=An account of the dissection of a porpess|journal=Philosophical Transactions of the Royal Society of London|volume=6|issue=69–80|year=1671|pages=2274–2279|bibcode = 1671RSPT....6.2274R|doi=10.1098/rstl.1671.0048|doi-access=free}}</ref><ref>{{cite journal|author=Susanne Prahl|title=Studies for the construction of epicranialen airway when porpoise (Phocoena phocoena Linnaeus, 1758)|journal=Dissertation for the Doctoral Degree of the Department of Biology of the Faculty of Mathematics, Computer Science and Natural Sciences at the University of Hamburg|year=2007|page=6}}</ref> It nevertheless referred to the porpoise as a fish, most likely not in the modern-day sense, where it refers to a zoological group, but the older reference as simply a creature of the sea (cf. for example ''star-fish'', ''cuttle-fish'', ''jelly-fish'' and ''whale-fish'').

===In captivity===
{{Main|Cetaceans in captivity}}
[[File:Harbor Porpoise Fjord Baelt Denmark.JPG|thumb|[[Harbour porpoise]] in captivity]]

Harbour porpoises have historically been kept in captivity, under the assumption that they would fare better than their dolphin counterparts due to their smaller size and shallow-water habitats. Up until the 1980s, they were consistently short-lived.<ref name="Porpoise"/><ref name=Collet1984>{{cite journal| author=Collet, A. | year=1984 | title=Live-Capture of Cetaceans for European Institutions | journal=Rep. Int. Whal. Comm. | volume=34 | pages=603–607 }}</ref> Harbour porpoises have a very long captive history, with poorly documented attempts as early as the 15th century,<ref name="Porpoise"/> and better documented starting in the 1860s and 1870s in [[London Zoo]], the now-closed [[Brighton]] Aquarium & Dolphinarium, and a zoo in Germany.<ref name=Collet1984/><ref>{{cite web|url= http://www.zootierliste.de/en/?klasse=1&ordnung=114&familie=11403&art=1110105&subhaltungen=2|title=North Atlantic Harbour porpoise|work=Zootierliste|access-date=3 July 2018}}</ref> At least 150 harbour porpoises have been kept worldwide, but only about 20 were actively caught for captivity.<ref name="Porpoise"/> The captive history is best documented from Denmark where about 100 harbour porpoises have been kept, most in the 1960s and 1970s. All but two were incidental catches in fishing nets or strandings. Nearly half of these died within a month of diseases caught before they were captured or from damage sustained during capture. Up until 1984, none lived for more than 14 months.<ref name="Porpoise"/><ref name=Collet1984/> Attempts to rehabilitate seven rescued individuals in 1986 only resulted in three that could be released 6 months later.<ref name="Porpoise"/> Very few have been brought into captivity later, but they have lived considerably longer. In recent decades, the only place keeping the species in Denmark is the Fjord & Bælt Centre, where three rescues have been kept, along with their offspring. Among the three rescues, one (father of world's first harbour porpoise born in captivity) lived for 20 years in captivity, another for 15 years,<ref>{{cite web|url=https://www.fyens.dk/kerteminde/Doedsfald-paa-FjordBaelt-Sif-blev-15-aar/artikel/3226969|title=Dødsfald på Fjord&Bælt: Sif blev 15 år|work=fyens.dk|date=1 February 2018|access-date=3 July 2018}}</ref><ref name=tv2fyn>{{cite web|url=https://www.tv2fyn.dk/artikel/eigil-er-doed|title=Tab for forskningen: Marsvinet Eigil er død|work=tv2fyn.dk|date=28 April 2016|access-date=3 July 2018}}</ref> while the third (mother of first born in captivity) is the world's oldest known harbour porpoise, being 28 years old in 2023.<ref>{{cite news| title=Marsvinet Freja bliver optaget i Guinness rekordbog | url=https://avisendanmark.dk/indland/marsvinet-freja-bliver-optaget-i-guinness-rekordbog | date=1 August 2023 | publisher=avisendanmark.dk | access-date=21 August 2023 }}</ref> The typical age reached in the wild is 14 years or less.<ref name=tv2fyn/><ref name="Read&Hohn"/><ref name=ADWHarbourPorpoise>{{cite web|url=http://animaldiversity.org/accounts/Phocoena_phocoena/|title=Phocoena phocoena, harbor porpoise|work=animaldiversity.org|access-date=3 July 2018}}</ref> Very few harbour porpoises have been born in captivity. Historically, harbour porpoises were often kept singly and those who were together often were not mature or of the same sex.<ref name="Porpoise"/> Disregarding one born more than 100 years ago that was the result of a pregnant female being brought into captivity,<ref name="Porpoise"/> the world's first full captive breeding was in 2007 in the Fjord & Bælt Centre, followed by another in 2009 in the [[Dolfinarium Harderwijk]], the Netherlands.<ref>{{cite web|url=https://phys.org/news/2009-05-porpoise-2nd-birth-captivity.html|title=Porpoise is 2nd to give birth in captivity|work=phys.org|date=8 May 2009|access-date=3 July 2018}}</ref> In addition to the few kept in Europe, harbour porpoise were displayed at the [[Vancouver Aquarium]] (Canada) until recently. This was a female that had beached herself onto [[Horseshoe Bay, West Vancouver|Horseshoe Bay]] in 2008 and a male that had done the same in 2011.<ref>{{cite web|url=https://www.vanaqua.org/experience/shows/porpoise|title=Spotlight on Porpoises|author=Vancouver Aquarium|work=Vancouver Aquarium|access-date=8 September 2015|archive-date=5 September 2015|archive-url=https://web.archive.org/web/20150905153432/http://www.vanaqua.org/experience/shows/porpoise|url-status=dead}}</ref><ref>{{cite web|url= http://www.nsnews.com/news/porpoise-rescued-in-horseshoe-bay-now-a-permanent-resident-of-aquarium-1.372119|title=Porpoise rescued in Horseshoe Bay now a permanent resident of aquarium|work=North Shore News|date=16 May 2012|access-date=3 July 2018}}</ref> They died in 2017 and 2016 respectively.<ref>{{cite web|url=https://vancouversun.com/news/local-news/harbour-porpoise-rescued-in-2008-dies-at-vancouver-aquarium|title=Harbour porpoise Daisy, rescued in 2008, dies at Vancouver Aquarium|work=Vancouver Sun|date=16 June 2017|access-date=3 July 2018}}</ref><ref>{{cite web|url=https://www.cbc.ca/news/canada/british-columbia/vancouver-aquarium-porpoise-1.3719481|title=Jack the harbour porpoise dies at Vancouver Aquarium|work=CBC|date=13 August 2016|access-date=3 July 2018}}</ref>

Finless porpoises have commonly been kept in Japan, as well as China and Indonesia. As of 1984, ninety-four in total had been in captivity in Japan, eleven in China, and at least two in Indonesia. As of 1986, three establishments in Japan had bred them, and there had been five recorded births. Three calves died moments after their birth, but two survived for several years.<ref name="Porpoise"/> This breeding success, combined with the results with harbour porpoise in Denmark and the Netherlands, proved that porpoises can be successfully bred in captivity, and this could open up new conservation options.<ref name="Porpoise"/><ref name=Goldfarb2016>{{cite journal| author=Goldfarb, B. | year=2016 | title=Can captive breeding save Mexico's vaquita?| journal=Conservation Biology | volume=353 | issue=6300 | pages=633–634 | doi=10.1126/science.353.6300.633 | pmid=27516576 }}</ref> The reopened [[Miyajima Public Aquarium]] (Japan) houses three finless porpoises.<ref>{{cite news|url= http://www.japantimes.co.jp/culture/2011/08/05/events/events-outside-tokyo/hiroshima-revamps-its-aquarium/#.Ve4pN_lVhBc|title=Hiroshima revamps its aquarium|newspaper=Japan Times|first=Wade|last=Bunnel}}</ref> As part of an attempt of saving the [[Yangtze finless porpoise|narrow-ridged (or Yangtze) finless porpoise]], several are kept in the Baiji Dolphinarium in China. After having been kept in captivity for 9 years, the first breeding happened in 2005.<ref>{{cite journal | author1=Ding Wang | author2=Yujiang Hao | author3=Kexiong Wang | author4=Qingzhong Zhao | author5=Daoquang Chen | author6=Zhuo Wei | author7=Xianfeng Zhang | year=2005 | title=The first Yangtze finless porpoise successfully born in captivity | journal=Environmental Science and Pollution Research | volume=12 | issue=5 | pages=247–250 | doi=10.1065/espr2005.08.284 | pmid=16206715 | s2cid=37638759 }}</ref>

Small numbers of Dall's porpoises have been kept in captivity in both the United States and Japan, with the most recent being in the 1980s. The first recorded instance of a Dall's taken for an aquarium was in 1956 captured off [[Santa Catalina Island (California)|Catalina Island]] in southern California.<ref>{{Cite web|date=2016-02-02|title=Wayback Machine: Dall's Porpoises in Captivity|url=https://www.dolphinproject.com/blog/wayback-machine-dalls-porpoises-in-captivity/|access-date=2021-09-17|website=Dolphin Project|language=en-US}}</ref> Dall's porpoises consistently failed to thrive in captivity. These animals often repeatedly ran into the walls of their enclosures, refused food, and exhibited [[skin sloughing]]. Almost all Dall's porpoises introduced to aquaria died shortly after, typically within days.<ref name="Porpoise"/><ref name=DallsInCaptivity>{{cite web|url=https://dolphinproject.com/blog/wayback-machine-dalls-porpoises-in-captivity/|title=Wayback Machine: Dall's Porpoises in Captivity|work=dolphinproject.com|access-date=3 July 2018}}</ref> Only two have lived for more than 60 days: a male reached 15 months at [[Marineland of the Pacific]] and another 21 months at a [[United States Navy Marine Mammal Program|United States Navy facility]].<ref name=DallsInCaptivity/>

As part of last-ditch effort of saving the extremely rare [[vaquita]] (the tiny remaining population is rapidly declining because of bycatch in gillnets), there have been attempts of transferring some to captivity.<ref name=Goldfarb2016/><ref>{{cite web|url=https://www.dw.com/en/captivity-last-hope-for-saving-the-vaquita/a-36799824|title=Captivity: Last hope for saving the vaquita?|work=Deutsche Welle|date=16 December 2016|access-date=3 July 2018}}</ref> The first and only caught for captivity were two females in 2017. Both became distressed and were rapidly released, but one of them died in the process.<ref>{{cite web|url=https://www.theatlantic.com/science/archive/2017/11/vaquita-porpoise-mexico-extinction/545204/|title=The Plan to Rescue a Nearly Extinct Porpoise Goes Terribly Awry|work=The Atlantic|date=9 November 2017|access-date=3 July 2018}}</ref><ref name=ScienceMagVaquita>{{cite web|url=https://www.science.org/content/article/update-after-death-captured-vaquita-conservationists-call-rescue-effort|title=Update: After death of captured vaquita, conservationists call off rescue effort|work=Science Magazine|date=9 November 2017|access-date=3 July 2018}}</ref> Soon after the project was abandoned.<ref name=ScienceMagVaquita/>

Only a single [[Burmeister's porpoise]] and a single [[spectacled porpoise]] have been kept in captivity. Both were stranded individuals that only survived a few days after their rescue.<ref name="Porpoise"/><ref>{{cite web|url=http://porpoise.org/about-porpoises/spectacled-porpoise/|title=Spectacled Porpoise|work=porpoise.org|access-date=3 July 2018}}</ref>

===Threats===

====Hunting====
[[File:FMIB 35846 Porpoise Fishery.jpeg|thumb|Traditional catch of [[harbour porpoise]] by lancing in [[Bay of Fundy]]]]
Porpoises and other smaller cetaceans have traditionally been hunted in many areas, at least in Asia, Europe and North America, for their meat and blubber. A dominant hunting technique is drive hunting, where a pod of animals is driven together with boats and usually into a bay or onto a beach. Their escape is prevented by closing off the route to the ocean with other boats or nets. This type of fishery for [[harbour porpoise]]s is best documented from the [[Danish straits]], where it occurred until the end of the 19th century (it was banned in 1899), and again during the shortages in [[World War I]] and [[World War II]].<ref>{{cite book |last1=Petersen |first1=Åge |title=Marsvin og marsvinjægere |date=1969 |publisher=Middelfart By- og Egnshistoriske Museum |location=Middelfart, Denmark}}</ref> The [[Inuit]] in the Arctic hunt harbour porpoises by shooting and drive hunt for [[Dall's porpoise]] still takes place in Japan. The number of individuals taken each year is in the thousands, although a quota of around 17,000 per year is in effect today<ref>{{cite journal |last1=Jefferson |first1=TA |last2=Braulik |first2=G |title=''Phocoenoides dalli'' |url=https://www.iucnredlist.org/species/17032/50370912 |journal=IUCN Red List of Threatened Species|date=22 March 2017 }}</ref> making it the largest direct hunt of any [[cetacean]] species in the world<ref name="smm">{{cite web |title=''Phocoenoides dalli'' (Dall's porpoise, Dall porpoise) |url=https://www.marinemammalscience.org/facts/phocoenoides-dalli/ |website=The Society for Marine Mammalogy}}</ref> and the sustainability of the hunt has been questioned.<ref name="IWChunt">{{cite journal |title=Report of the Sub-Committee on Small Cetaceans |journal=International Whaling Commission |date=2008}}</ref><ref name="smm2">{{cite web |last1=Wells |first1=RS |title=Letter to Japanese Government Regarding Dolphin and Small Whale Hunts |url=https://www.marinemammalscience.org/letters/letter-to-japanese-government-regarding-dolphin-and-small-whale-hunts/ |website=The Society for Marine Mammalogy|date=29 May 2012 }}</ref>

====Fishing====
{{Main|Cetacean bycatch}}
[[File:Vaquita2 Olson NOAA.jpg|thumb|A [[vaquita]] swimming in the [[Gulf of California]].]]
Porpoises are highly affected by [[bycatch]]. Many porpoises, mainly the [[vaquita]], are subject to great mortality due to [[gillnetting]]. Although it is the world's most endangered marine cetacean, the vaquita continues to be caught in small-mesh gillnet fisheries throughout much of its range. Incidental mortality caused by the fleet of El Golfo de Santa Clara was estimated to be at around 39 vaquitas per year, which is over 17% of the population size.<ref>{{cite journal|last1=D'agrosa|first1=C.|last2=Lennert-Cody|first2=C. E.|last3=Vidal|first3=O.|year=2000|title=Vaquita Bycatch in Mexico's Artisanal Gillnet Fisheries: Driving a Small Population to Extinction|journal=Conservation Biology|volume=14|issue=4|doi=10.1046/j.1523-1739.2000.98191.x|pages=1110–1119|bibcode=2000ConBi..14.1110D |s2cid=44057831}}</ref> Harbour porpoises also suffer drowning by gillnetting, but on a less threatening scale due to their high population; their mortality rate per year increases a mere 5% due to this.<ref>{{cite journal|url=https://www.umb.edu/editor_uploads/images/Caswell_etal_EcolAppl1998.pdf|first1=Hal|last1=Caswell|first2=Solange|last2=Brault|first3=Andrew|last3=Read|first4=Tim|last4=Smith|title=Harbor Porpoise and Fisheries: an Uncertainty Analysis of Incidental Mortality|journal=Ecological Applications|volume=8|issue=4|year=1998|access-date=30 October 2015|pages=1226–1238|doi=10.1890/1051-0761(1998)008[1226:hpafau]2.0.co;2|archive-date=8 December 2015|archive-url=https://web.archive.org/web/20151208132734/https://www.umb.edu/editor_uploads/images/Caswell_etal_EcolAppl1998.pdf|url-status=dead}}</ref>

The fishing market, historically has always had a porpoise bycatch. Today, the [[Marine Mammal Protection Act of 1972]] has enforced the use of safer fishing equipment to reduce bycatch.<ref>{{cite newsgroup|title=America's Favorite Fish Tainted by Porpoise Deaths|last=Croft|first=Chris|url=https://www.latimes.com/archives/la-xpm-1988-04-17-op-1956-story.html|access-date=30 October 2015}}</ref>

====Environmental hazards====
{{See also|Marine mammals and sonar}}
Porpoises are very sensitive to [[anthropogenic effect|anthropogenic]] disturbances,<ref name=":0">{{cite journal |title=Harbour porpoises (''Phocoena phocoena'') stranded along the southern North Sea: an assessment through metallic contamination |last1=Mahfouz |first1=C |last2=Henry |first2=F |last3=Courcot |first3=L |last4=Pezeril |first4=S |last5=Bouveroux |first5=T |last6=Dabin |first6=W |last7=Jauniaux |first7=T |last8=Khalaf |first8=G |last9=Amara |first9=R |year=2014 |journal= Environmental Research|doi=10.1016/j.envres.2014.06.006 |pmid=24981825 |volume=133 |pages=266–73|bibcode=2014ER....133..266M |hdl=2268/169176 |url=http://orbi.ulg.ac.be/handle/2268/169176 |hdl-access=free }}</ref> and are [[keystone species]], which can indicate the overall health of the marine environment.<ref name=":0" /> Populations of harbor porpoises in the North and Baltic Seas are under increasing pressure from anthropogenic causes such as offshore construction, ship traffic, fishing, and military exercises.<ref>{{cite journal |last1=Siebert |first1=Ursula |last2=Pozniak |first2=Blazej |last3=Hansen |first3=Kirstin |last4=Anderson |last5=Nordstrom |first5=Gwyneth |last6=Teilmann |first6=Jonas |last7=Van Elk |first7=Niels |last8=Vossen |first8=Ardnt |last9=Dietz |first9=Rune |year=2011 |title=Investigations of Thyroid and Stress Hormones in Free-Ranging and Captive Harbor Porpoises (''Phocoena phocoena''): A Pilot Study |journal=Aquatic Mammals |volume=37 |issue=4 |pages=443–453 |doi=10.1578/am.37.4.2011.443}}</ref> Increasing pollution is a serious problem for marine mammals. Heavy metals and [[plastic pollution|plastic waste]] are not biodegradable, and sometimes cetaceans consume these hazardous materials, mistaking them for food items. As a result, the animals are more susceptible to diseases and have fewer offspring.<ref name=wdcs>{{cite book |author=Cara E. Miller |title=Current State of Knowledge of Cetacean Threats, Diversity, and Habitats in the Pacific Islands Region |publisher=Whale and Dolphin Conservation Society |year=2007 |access-date=5 September 2015 |isbn=978-0-646-47224-9 |url=http://uk.whales.org/sites/default/files/whales-and-dolphins-in-the-pacific-islands.pdf |archive-url=https://web.archive.org/web/20150908003502/http://uk.whales.org/sites/default/files/whales-and-dolphins-in-the-pacific-islands.pdf |archive-date=8 September 2015  }}</ref> Harbour porpoises from the [[English Channel]] were found to have accumulated heavy metals.<ref name=":0" />

The military and geologists employ strong [[sonar]] and produce an increases in noise in the oceans. [[Marine mammal]]s that make use of [[biosonar]] for orientation and communication are not only hindered by the extra noise, but may race to the surface in panic. This may lead to a bubbling out of blood gases, and the animal then dies because the blood vessels become blocked, so-called [[decompression sickness]].<ref>{{cite book |author1=M. Andre |author2=T. Johansson |author3=E. Delory |author4=M. van der Schaar |title=Europe Oceans 2005 |chapter=Cetacean biosonar and noise pollution |publisher=Oceans 2005–Europe |year=2005 |volume=2 |pages=1028–1032 Vol. 2 |doi=10.1109/OCEANSE.2005.1513199 |isbn=978-0-7803-9103-1 |s2cid=31676969 }}</ref> This effect, of course, only occurs in porpoises that dive to great depths, such as Dall's porpoise.<ref>{{cite journal |author=Kastelein, R. A. |author2=Schop, J. |author3=Gransier, R. |author4=Steen, N. |author5=Jennings, N. |title=Effect of Series of 1 to 2 kHz and 6 to 7 kHz Up-Sweeps and Down-Sweeps on the Behavior of a Harbor Porpoise (''Phocoena phocoena'') |doi=10.1578/AM.40.3.2014.232 | volume=40 |issue=3 |journal=Aquatic Mammals |pages=232–242|year=2014 }}</ref>

Additionally, civilian vessels produce sonar waves to measure the depth of the body of water in which they are. Similar to the navy, some boats produce waves that attract porpoises, while others may repel them. The problem with the waves that attract is that the animal may be injured or even killed by being hit by the vessel or its propeller.<ref>{{cite journal |last1=Culik |first1=B. |last2=von Dorrien |first2=C. |last3=Muller |first3=V. |last4=Conrad |first4=M. |year=2015 |title=Bioacoustics |journal=The International Journal of Animal Sound and Its Recording |volume=24 |issue=3 |issn=0952-4622}}</ref>

===Conservation===
[[File:Porpoise Sculpture with Flowers and Fountains - Waterfront Park - Kelowna - British Columbia - Canada (8008022011).jpg|thumb|right|A porpoise sculpture in Kelowna, British Columbia, Canada]]

The harbour porpoise, spectacled porpoise, Burmeister's porpoise, and Dall's porpoise are all listed on Appendix II of the [[Convention on the Conservation of Migratory Species of Wild Animals]] (CMS).<ref name="Appendices">"{{cite web|url=http://www.cms.int/en/convention-text|title=Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008|date=5 March 2009}}</ref><ref>{{cite journal |author=HELCOM |author-link=HELCOM |year=2013 |title=HELCOM Red List of Baltic Sea species in danger of becoming extinct |journal=Baltic Sea Environmental Proceedings |issue=140 |page=92 |url=http://helcom.fi/Lists/Publications/BSEP140.pdf  |archive-url=https://web.archive.org/web/20141007002944/http://helcom.fi/Lists/Publications/BSEP140.pdf |archive-date=7 October 2014 }}</ref> In addition, the Harbour porpoise is covered by the [[Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas]] (ASCOBANS), the [[ACCOBAMS|Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area]] (ACCOBAMS) and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia.<ref>{{cite web|url=http://www.cms.int/aquatic-mammals/sites/default/files/basic_page_documents/MoU_E.pdf |archive-url=https://web.archive.org/web/20150919134833/http://www.cms.int/aquatic-mammals/sites/default/files/basic_page_documents/MoU_E.pdf |archive-date=2015-09-19 |url-status=live|title=Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia|work=[[Convention on the Conservation of Migratory Species of Wild Animals]]|pages=1–6}}</ref> Their conservation statuses are either at [[least concern]] or [[data deficient]].<ref>{{cite web|url=http://www.cms.int/reports/small_cetaceans/img/Odontocete_poster.pdf|title=Odontocetes: The Toothed Whales |publisher=[[International Union for Conservation of Nature|IUCN]], [[ASCOBANS]], [[World Wide Fund for Nature|WWF]], [[Convention on the Conservation of Migratory Species of Wild Animals|CMS]], [[ACCOBAMS]]|archive-url=https://web.archive.org/web/20151208124558/http://www.cms.int/reports/small_cetaceans/img/Odontocete_poster.pdf |archive-date=8 December 2015}}</ref>

As of 2014, only 505 [[Yangtze finless porpoise]]s remained in the main section of the Yangtze, with an alarming population density in Ezhou and Zhenjiang. While many threatened species decline rate slows after their classification, population decline rates of the porpoise are actually accelerating. While population decline tracked from 1994 to 2008 has been pegged at a rate of 6.06% annually, from 2006 to 2012, the porpoise population decreased by more than half. Finless porpoise population decrease of 69.8% in just a 22-year span from 1976 to 2000. 5.3%.<ref>{{cite journal|last1=Hashimoto|first1=M.|last2=Shirakihara|first2=K.|last3=Shirakihara|first3=M.|last4=Hiramatsu|first4=K.|year=2013|title=Estimating the rate of increase for the finless porpoise with special attention to predictions for the inland sea population in japan|journal=Population Ecology|volume=55|issue=3|pages=441–449|doi=10.1007/s10144-013-0374-5|bibcode=2013PopEc..55..441H |s2cid=15843140}}</ref> A majority of factors of this population decline are being driven by the massive growth in Chinese industry since 1990 which caused increased shipping and pollution and ultimately [[environmental degradation]].<ref>{{cite journal | last1 = Mei | first1 = Zhigang | last2 = Zhang | first2 = Xinqiao | last3 = Huang | first3 = Shiang-Lin | last4 = Zhao | first4 = Xiujiang | last5 = Hao | first5 = Yujiang | last6 = Zhang | first6 = Lin | last7 = Qian | first7 = Zhengyi | last8 = Zheng | first8 = Jinsong | last9 = Wang | first9 = Kexiong | last10 = Wang | first10 = Ding | year = 2014 | title = The Yangtze Finless Porpoise: On an Accelerating Path to Extinction? | url = http://ir.ihb.ac.cn/handle/342005/19995 | journal = Biological Conservation | volume = 172 | pages = 117–23 | doi = 10.1016/j.biocon.2014.02.033 | bibcode = 2014BCons.172..117M | access-date = 27 January 2019 | archive-date = 29 May 2020 | archive-url = https://web.archive.org/web/20200529104049/http://ir.ihb.ac.cn/handle/342005/19995 | url-status = dead }}</ref> Some of these can be seen in damming of the river as well as [[illegal, unreported and unregulated fishing|illegal fishing]] activity. To protect the species, China's Ministry of Agriculture classified the species as being National First Grade Key Protected Wild Animal, the strictest classification by law, meaning it is illegal to bring harm to a porpoise. Protective measures in the [[Tian-e-Zhou Oxbow Nature Reserve]] has increased its population of porpoises from five to forty in 25 years. The [[Chinese Academy of Sciences]]' [[Wuhan Institute of Hydrobiology]] has been working with the [[World Wildlife Fund]] to ensure the future for this subspecies, and have placed five porpoises in another well-protected area, the He-wang-miao oxbow.<ref>{{cite web|url=http://www.worldwildlife.org/stories/saving-the-finless-porpoise|title=Saving the Finless Porpoise|first1=Karin|last1=Krchnak|date=30 September 2014|access-date=25 October 2015|work=[[World Wildlife Fund]]}}</ref> Five protected natural reserves have been established in areas of the highest population density and mortality rates with measures being taken to ban patrolling and harmful fishing gear in those areas. There have also been efforts to study porpoise biology to help specialize conservation through captivation breeding. The Baiji Dolphinarium, was established in 1992 at the Institute of Hydrobiology of the Chinese Academy of Sciences in Wuhan which allowing the study of behavioral and biological factors affecting the finless porpoise, specifically breeding biology like seasonal changes in reproductive hormones and breeding behavior.<ref>{{cite journal|last1=Wang|first1=D.|last2=Hao|first2=Y.|last3=Wang|first3=K.|last4=Zhao|first4=Q.|last5=Chen|first5=D.|last6=Wei| first6=Z.|last7=Zhang|first7=X.|year=2005|title=the first yangtze finless porpoise successfully born in captivity|journal=Environmental Science and Pollution Research International|volume=12|issue=5|pages=247–250|doi=10.1065/espr2005.08.284|pmid=16206715|s2cid=37638759}}</ref>

Because [[vaquita]]s are indigenous to the Gulf of California, Mexico is leading conservation efforts with the creation of the [[International Committee for the Recovery of the Vaquita]] (CIRVA), which has tried to prevent the accidental deaths of vaquitas by outlawing the use of fishing nets within the vaquita's habitat.<ref>{{cite web|last1=Barlow|first1=J.|year=2014|title=Vaquita (Phocoena sinus)|url=http://www.edgeofexistence.org/mammals/species_info.php?id=78|work=Edge of Existence programme|publisher=Zoological Society of London|access-date=25 October 2015|archive-date=26 October 2016|archive-url=https://web.archive.org/web/20161026123310/http://www.edgeofexistence.org/mammals/species_info.php?id=78}}</ref> CIRVA has worked together with the [[CITES]], the [[Endangered Species Act]], and the [[Marine Mammal Protection Act of 1972|Marine Mammal Protection Act]] (MMPA) to nurse the vaquita population back to a point at which they can sustain themselves.<ref name="NOAA_Vaquita">{{cite web|title=Gulf of California Harbor Porpoise / Vaquita / Cochito (''Phocoena sinus'')|url=http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/vaquita.htm|publisher=NOAA Fisheries–Office of Protected Resources|work= Species Information|date= 8 July 2013|access-date=20 January 2014}}</ref> CIRVA concluded in 2000 that between 39 and 84 individuals are killed each year by such gillnets. To try to prevent extinction, the Mexican government has created a nature reserve covering the upper part of the Gulf of California and the [[Colorado River delta]]. They have also placed a temporary ban on fishing, with compensation to those affected, that may pose a threat to the vaquita.<ref>{{cite web|url=http://www.iucn-csg.org/index.php/2015/04/24/president-of-mexico-launches-plan-to-save-the-vaquita/|title=President of Mexico launches plan to save the vaquita|author=Gill Braulik|date=24 April 2015|access-date=25 October 2015|work=IUCN SSC–Cetacean Specialist Group|archive-date=18 October 2015|archive-url=https://web.archive.org/web/20151018131533/http://www.iucn-csg.org/index.php/2015/04/24/president-of-mexico-launches-plan-to-save-the-vaquita/|url-status=dead}}</ref>