Editing Dolphin (section)

==Threats==
[[File:Bottle-nosed-dolphin-Lobomycosis-disease.jpg|thumb|Lesions in the [[dorsum (anatomy)|dorsal]] fin of a bottlenose dolphin caused by [[lobomycosis]], a [[mycosis|fungal infection]] of the skin.]]

Dolphins have few marine enemies. Some species or specific populations have none, making them [[apex predator]]s. For most of the smaller species of dolphins, only a few of the larger sharks, such as the [[bull shark]], [[dusky shark]], [[tiger shark]] and [[great white shark]], are a potential risk, especially for calves.<ref>Michael R. Heithaus (1999), ''Predator-prey and competitive interactions between sharks (order Selachii) and dolphins (parvorder Odontoceti): a review''</ref> Some of the larger dolphin species, especially [[orcas]], may also prey on smaller dolphins, but this seems rare.<ref>[[Nadia Drake]] for WIRED (2013), [https://www.wired.com/2013/05/killer-whale-flips-dolphin/ Photographer Captures Stunning Killer Whale Attack on Dolphin], article. Retrieved March 14, 2022.</ref> Dolphins also suffer from a wide variety of diseases and parasites.<ref>{{cite journal | last1 = Bossart | first1 = G. D. | year = 2007 | title = Emerging diseases in marine mammals: from dolphins to manatees | url = http://www.marineland.net/images/pdfs/Bossart%20Emerging%20Dis.pdf | journal = Microbe | volume = 2 | issue = 11 | pages = 544–549 | url-status = dead | archive-url = https://web.archive.org/web/20140114091150/http://www.marineland.net/images/pdfs/Bossart%20Emerging%20Dis.pdf | archive-date = January 14, 2014 }}</ref><ref>{{cite journal|last=Woodard|first=J. C.|author2=Zam, S. G. |author3=Caldwell, D. K. |author4= Caldwell, M. C. |title=Some Parasitic Diseases of Dolphins|journal=Veterinary Pathology|year=1969|volume=6|issue=3|pages=257–272|doi=10.1177/030098586900600307|pmid=5817449|s2cid=26842976|doi-access=free}}</ref>  The [[Cetacean morbillivirus]] in particular has been known to cause regional [[epizootics]] often leaving hundreds of animals of various species dead.<ref>{{Cite journal | last1 = Bellière | first1 = E. N. | last2 = Esperón | first2 = F. | last3 = Sánchez-Vizcaíno | first3 = J. M. | doi = 10.1016/j.meegid.2011.08.018 | title = Genetic comparison among dolphin morbillivirus in the 1990–1992 and 2006–2008 Mediterranean outbreaks | journal = Infection, Genetics and Evolution | volume = 11 | issue = 8 | pages = 1913–1920 | year = 2011 | pmid = 21888991 | bibcode = 2011InfGE..11.1913B }}</ref><ref>Jane J. Lee for [[National Geographic Society|National Geographic]] (2013), [https://www.nationalgeographic.com/?rptregcta=reg_free_np&rptregcampaign=20131016_rw_membership_r1p_us_se_w What's Killing Bottlenose Dolphins? Experts Discover Cause.], article. Retrieved December 4, 2013.</ref> Symptoms of infection are often a severe combination of [[pneumonia]], [[encephalitis]] and damage to the immune system, which greatly impair the cetacean's ability to swim and stay afloat unassisted.<ref name=mass >{{Cite journal | last1 = Guardo | first1 = G. D. | last2 = Marruchella | first2 = G. | last3 = Agrimi | first3 = U. | last4 = Kennedy | first4 = S. | title = Morbillivirus Infections in Aquatic Mammals: A Brief Overview | doi = 10.1111/j.1439-0442.2005.00693.x | journal = Journal of Veterinary Medicine, Series A | volume = 52 | issue = 2 | pages = 88–93 | year = 2005 | pmid = 15737178 | hdl = 11575/80640 | hdl-access = free }}</ref><ref name=austurs>{{Cite journal | last1 = Stone | first1 = B. M. | last2 = Blyde | first2 = D. J. | last3 = Saliki | first3 = J. T. | last4 = Blas-Machado | first4 = U. | last5 = Bingham | first5 = J. | last6 = Hyatt | first6 = A. | last7 = Wang | first7 = J. | last8 = Payne | first8 = J. | last9 = Crameri | first9 = S. | doi = 10.1111/j.1751-0813.2011.00849.x | title = Fatal cetacean morbillivirus infection in an Australian offshore bottlenose dolphin (Tursiops truncatus) | journal = Australian Veterinary Journal | volume = 89 | issue = 11 | pages = 452–457 | year = 2011 | pmid = 22008125 | doi-access = free }}</ref> A study at the U.S. National Marine Mammal Foundation revealed that dolphins, like humans, develop a natural form of [[Diabetes mellitus|type 2 diabetes]] which may lead to a better understanding of the disease and new treatments for both humans and dolphins.<ref>{{cite web|url=http://nmmpfoundation.org/pressrelease.htm|archive-url=https://web.archive.org/web/20100411081512/http://nmmpfoundation.org/pressrelease.htm|archive-date=April 11, 2010|date=February 18, 2010 |title=Scientists Find Clues in Dolphins to Treat Diabetes in Humans |author=US National Marine Mammal Foundation |access-date=February 20, 2010}}</ref>

Dolphins can tolerate and recover from extreme injuries such as [[shark]] bites although the exact methods used to achieve this are not known. The [[healing]] process is rapid and even very deep wounds do not cause dolphins to [[hemorrhage]] to death. Furthermore, even gaping wounds restore in such a way that the animal's body shape is restored, and infection of such large wounds seems rare.<ref>{{cite web |url=http://explore.georgetown.edu/news/?ID=57991&PageTemplateID=295 |title=Dolphins' "Remarkable" Recovery from Injury Offers Important Insights for Human Healing |author=Georgetown University Medical Center |access-date=July 26, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20111205105601/http://explore.georgetown.edu/news/?ID=57991&PageTemplateID=295 |archive-date=December 5, 2011 |author-link=Georgetown University Medical Center }}</ref>

A study published in the journal ''Marine Mammal Science'' suggests that at least some dolphins survive shark attacks using everything from sophisticated combat moves to teaming up against the shark.<ref>{{Cite news|url=http://www.seeker.com/shark-vs-dolphin-battles-can-have-surprising-outcomes-1768940807.html|title=Shark vs. Dolphin Battles Can Have Surprising Outcomes|last=Viegas|first=Jen|date=August 14, 2014|newspaper=Seeker – Science. World. Exploration. Seek for yourself.|access-date=November 27, 2016}}</ref><ref>{{cite web|url=http://animalquestions.org/mammals/dolphins/can-dolphins-kill-sharks/|title=Can Dolphins Kill Sharks?|date=December 2, 2011|website=animalquestions.org}}</ref><ref>{{cite web|url=http://www.elasmo-research.org/education/topics/b_corner.htm|title=Do dolphins really beat up sharks?|publisher=ReefQuest Centre for Shark Research}}</ref>

===Humans===
{{See also|Dolphin drive hunting|Cetacean bycatch}}
[[File:Whaling in the Faroe Islands.jpg|thumb|Dead Atlantic white-sided dolphins in [[Hvalba]] on the [[Faroe Islands]], killed in a [[dolphin drive hunting|drive hunt]].|alt=Rows of dead dolphin lying on concrete]]
Some dolphin species are at risk of extinction, especially some river dolphin species such as the Amazon river dolphin, and the [[Ganges river dolphin|Ganges]] and [[Baiji|Yangtze river dolphin]], which are critically or seriously endangered. A 2006 survey found no individuals of the Yangtze river dolphin. The species now appears to be [[functionally extinct]].<ref>{{cite web |title= Yangtze dolphin may be extinct |author=Douglas Williams for Shanghai Daily |date=December 4, 2006 |url=http://english.cri.cn/3100/2006/12/04/63@170330.htm |archive-url=https://web.archive.org/web/20180114073844/http://english.cri.cn/3100/2006/12/04/63@170330.htm |url-status=dead |archive-date=January 14, 2018 |access-date=January 13, 2018}}</ref>

[[Pesticides]], heavy metals, plastics, and other industrial and agricultural pollutants that do not disintegrate rapidly in the environment concentrate in predators such as dolphins.<ref>{{cite web|first=Stephen R. |last=Palumbi |author-link=Stephen Palumbi |url=https://www.youtube.com/watch?v=ooAIIeo4AJQ&feature=youtube_gdata | archive-url=https://ghostarchive.org/varchive/youtube/20211211/ooAIIeo4AJQ| archive-date=2021-12-11 | url-status=live|title=TED: Stephen Palumbi: Following the mercury trail |via=YouTube |date=June 30, 2010 |access-date=July 25, 2011}}{{cbignore}}</ref> Injuries or deaths due to collisions with boats, especially their [[propeller]]s, are also common.

Various fishing methods, most notably purse [[seine fishing]] for [[tuna]] and the use of [[drift net|drift]] and [[gill net]]s, unintentionally kill many dolphins.<ref name="Clover2008">{{cite book|last=Clover|first=Charles|title=The End of the Line: How Overfishing is Changing the World and what We Eat|url={{google books |plainurl=y |id=OMY-gEKMod8C}}|year=2008|publisher=University of California Press|isbn=978-0-520-25505-0}}</ref> Accidental [[by-catch]] in gill nets and incidental captures in antipredator nets that protect marine fish farms are common and pose a risk for mainly local dolphin populations.<ref name="Díaz López, 2006">{{Cite journal
|last1=Díaz López| first1=Bruno
|last2=Bernal Shirai |first2=J.A.
| year=2006
| title=Bottlenose dolphin (''Tursiops truncatus'') presence and incidental capture in a marine fish farm on the north-eastern coast of Sardinia (Italy)
| journal=Journal of the Marine Biological Association of the UK
| volume=87
| pages=113–117
| doi=10.1017/S0025315407054215| s2cid=86115152
}}</ref><ref name="Díaz López, 2006b">{{Cite journal
| last=Díaz López| first=Bruno
| year=2006
| title= Interactions between Mediterranean bottlenose dolphins (''Tursiops truncatus'') and gillnets off Sardinia, Italy
| journal= ICES Journal of Marine Science
| volume=63
| pages=946–951
| doi=10.1016/j.icesjms.2005.06.012
| issue=5| bibcode=2006ICJMS..63..946D
| doi-access=free
}}</ref> In some parts of the world, such as [[Taiji, Wakayama|Taiji]] in Japan and the [[Faroe Islands]], dolphins are traditionally considered food and are killed in [[harpoon]] or [[dolphin drive hunting|drive hunts]].<ref name="auto">
{{cite web
 |last        = Matsutani
 |first       = Minoru
 |url         = http://search.japantimes.co.jp/cgi-bin/nn20090923f1.html
 |title       = Details on how Japan's dolphin catches work
 |work   = [[Japan Times]]
 |date        = September 23, 2009
 |page        = 3
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20090927022232/http://search.japantimes.co.jp/cgi-bin/nn20090923f1.html
 |archive-date = September 27, 2009
}}</ref> Dolphin meat is high in mercury and may thus pose a health danger to humans when consumed.<ref>
{{cite web
|last=Johnston |first=Eric
|url=http://search.japantimes.co.jp/cgi-bin/nn20090923f2.html
|title=Mercury danger in dolphin meat
|work=[[Japan Times]]
|date=September 23, 2009
|page=3
}}</ref>

[[Queensland|Queensland's]] [[shark culling]] program, which has killed roughly 50,000 sharks since 1962, has also killed thousands of dolphins as bycatch.<ref>{{cite web| url = https://www.news.com.au/technology/science/animals/aussie-shark-population-is-staggering-decline/news-story/49e910c828b6e2b735d1c68e6b2c956e| title = Aussie shark population in staggering decline. Rhian Deutrom. December 14, 2018. Retrieved December 26, 2018.}}</ref><ref name="afd_cull"/> "Shark control" programs in both Queensland and [[New South Wales]] use [[shark nets]] and [[drum line (shark control)|drum lines]], which entangle and kill dolphins.<ref>{{cite web |url = https://www.marineconservation.org.au/pages/shark-culling.html |title = "Shark Culling". marineconservation.org.au. Archived from the original on 2018-10-02. Retrieved December 26, 2018. |archive-url=https://web.archive.org/web/20181002102324/https://www.marineconservation.org.au/pages/shark-culling.html |archive-date=2 October 2018 |url-status=dead}}</ref> Queensland's "shark control" program has killed more than 1,000 dolphins in recent years,<ref name="afd_cull">{{cite web| url = http://www.afd.org.au/news-articles/queenslands-shark-control-program-has-snagged-84000-animals| title = Action for Dolphins. Queensland's Shark Control Program Has Snagged 84,000 Animals. Thom Mitchell. November 20, 2015. Retrieved December 26, 2018.| date = May 12, 2023}}</ref> and at least 32 dolphins have been killed in Queensland since 2014.<ref>{{cite web| url = https://hsi.org.au/blog/separating-fact-from-fiction-in-qlds-shark-culling-program| title = ''Separating fact from fiction in QLD's shark culling program.'' Nicola Beynon. October 19, 2018. Retrieved December 26, 2018| date = October 19, 2018}}</ref> A [[shark culling]] program in [[KwaZulu-Natal]] has killed at least 2,310 dolphins.<ref>{{cite web| url = http://www.sharkangels.org/index.php/media/news/157-shark-nets| title = "Shark Nets". sharkangels.org. Retrieved December 26, 2018.}}</ref>

[[Dolphin safe label]]s attempt to reassure consumers that fish and other marine products have been caught in a dolphin-friendly way. The earliest campaigns with "dolphin safe" labels were initiated in the 1980s as a result of cooperation between marine activists and the major tuna companies, and involved decreasing incidental dolphin kills by up to 50% by changing the type of nets used to catch tuna. The dolphins are netted only while fishermen are in pursuit of smaller tuna. Albacore are not netted this way, making albacore the only truly dolphin-safe tuna.<ref>{{cite web |title=Time of Truth For US Dolphin Safe Logos |url=http://www.atuna.com/NewsArchive/ViewArticle.asp?ID=12719 |website=atuna |access-date=August 29, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20151015221118/http://www.atuna.com/NewsArchive/ViewArticle.asp?ID=12719 |archive-date=October 15, 2015}}</ref>
Loud underwater noises, such as those resulting from [[navy|naval]] [[sonar]] use, live firing exercises, and certain [[offshore construction]] projects such as [[wind farm]]s, may be harmful to dolphins, increasing stress, damaging hearing, and causing [[decompression sickness]] by forcing them to surface too quickly to escape the noise.<ref>{{cite news
|title= Navy sonar may be killing whales, dolphins
|author=CBC news
|url=https://www.cbc.ca/amp/1.358039
|access-date= October 27, 2008
|publisher=CBC News
|date=October 9, 2003}}</ref><ref>{{cite web
|title=Npower renewables Underwater noise & vibration, section 9.4
|url=http://www.natwindpower.co.uk/northhoyle/pdfs/fepa/chapter9.pdf
|archive-url=https://web.archive.org/web/20070722160651/http://www.natwindpower.co.uk/northhoyle/pdfs/fepa/chapter9.pdf
|archive-date=July 22, 2007
|access-date= October 27, 2008}}</ref>

Dolphins and other smaller cetaceans are also hunted in an activity known as dolphin drive hunting. This is accomplished by driving a pod 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. Dolphins are hunted this way in several places around the world, including the [[Solomon Islands]], the [[Faroe Islands]], [[Peru]], and Japan, the most well-known practitioner of this method. By numbers, dolphins are mostly hunted for their [[whale meat|meat]], though some end up in [[dolphinarium]]s. Despite the controversial nature of the hunt resulting in international criticism, and the possible health risk that the often polluted meat causes, thousands of dolphins are caught in drive hunts each year.

=== Impacts of climate change ===
{{See also|Effects of climate change on oceans}}
Dolphins are marine mammals with broad geographic extent, making them susceptible to climate change in various ways. The most common effect of climate change on dolphins is the increasing water temperatures across the globe.<ref name="Evans-2013-2">{{Cite journal |last1=Evans |first1=Peter G.H. |last2=Bjørge |first2=Arne |date=November 28, 2013 |title=Impacts of climate change on marine mammals |url=https://www.seawatchfoundation.org.uk/wp-content/uploads/2015/05/Evans-Bj%C3%B8rge_2013.pdf |journal=MCCIP Science Review 2013}}</ref> This has caused a large variety of dolphin species to experience range shifts, in which the species move from their typical geographic region to cooler waters.<ref name="Würsig-2001"/><ref>{{Cite journal |last1=Salvadeo |first1=CJ |last2=Lluch-Belda |first2=D |last3=Gómez-Gallardo |first3=A |last4=Urbán-Ramírez |first4=J |last5=MacLeod |first5=CD |date=2010-03-10 |title=Climate change and a poleward shift in the distribution of the Pacific white-sided dolphin in the northeastern Pacific |url=https://www.int-res.com/abstracts/esr/v11/n1/p13-19/ |journal=Endangered Species Research |language=en |volume=11 |issue=1 |pages=13–19 |doi=10.3354/esr00252 |issn=1863-5407 |doi-access=free}}</ref> Another side effect of increasing water temperatures is the increase in [[Harmful algal bloom|harmful algae blooms]], which has caused a mass die-off of bottlenose dolphins.<ref name="Evans-2013-2" />

In [[California]], the 1982–83 [[El Niño]] warming event caused the near-bottom spawning [[market squid]] to leave southern California, which caused their predator, the [[pilot whale]], to also leave. As the market squid returned six years later, [[Risso's dolphin|Risso's dolphins]] came to feed on the squid. [[Bottlenose dolphin|Bottlenose dolphins]] expanded their range from southern to central California, and stayed even after the warming event subsided.<ref name="Würsig-2001">{{Citation |last1=Würsig |first1=Bernd |title=Global Climate Change and Marine Mammals |date=2001 |url=https://doi.org/10.1007/978-1-4615-0529-7_17 |work=Marine Mammals: Biology and Conservation |pages=589–608 |editor-last=Evans |editor-first=Peter G. H. |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-1-4615-0529-7_17 |isbn=978-1-4615-0529-7 |access-date=2021-05-01 |last2=Reeves |first2=Randall R. |last3=Ortega-Ortiz |first3=J. G. |editor2-last=Raga |editor2-first=Juan Antonio}}</ref> The [[Pacific white-sided dolphin]] has had a decline in population in the southwest [[Gulf of California]], the southern boundary of their distribution. In the 1980s they were abundant with group sizes up to 200 across the entire cool season. Then, in the 2000s, only two groups were recorded with sizes of 20 and 30, and only across the central cool season. This decline was not related to a decline of other marine mammals or prey, so it was concluded to have been caused by climate change as it occurred during a period of warming. Additionally, the Pacific white-sided dolphin had an increase in occurrence on the west coast of [[Canada]] from 1984 to 1998.<ref>{{Cite journal |last1=Salvadeo |first1=CJ |last2=Lluch-Belda |first2=D |last3=Gómez-Gallardo |first3=A |last4=Urbán-Ramírez |first4=J |last5=MacLeod |first5=CD |date=2010-03-10 |title=Climate change and a poleward shift in the distribution of the Pacific white-sided dolphin in the northeastern Pacific |url=https://www.int-res.com/abstracts/esr/v11/n1/p13-19/ |journal=Endangered Species Research |language=en |volume=11 |issue=1 |pages=13–19 |doi=10.3354/esr00252 |issn=1863-5407 |doi-access=free}}</ref>

In the [[Mediterranean]], [[Sea surface temperature|sea surface temperatures]] have increased, as well as [[salinity]], [[upwelling]] intensity, and sea levels. Because of this, prey resources have been reduced causing a steep decline in the [[short-beaked common dolphin]] Mediterranean subpopulation, which was deemed endangered in 2003. This species now only exists in the [[Alboran Sea]], due to its high productivity, distinct ecosystem, and differing conditions from the rest of the Mediterranean.<ref>{{Cite journal |last1=Cañadas |first1=A. |last2=Vázquez |first2=J.A. |date=2017-07-01 |title=Common dolphins in the Alboran Sea: Facing a reduction in their suitable habitat due to an increase in Sea surface temperature |journal=Deep Sea Research Part II: Topical Studies in Oceanography |language=en |volume=141 |pages=306–318 |bibcode=2017DSRII.141..306C |doi=10.1016/j.dsr2.2017.03.006 |issn=0967-0645 |doi-access=free}}</ref>

In northwest Europe, many dolphin species have experienced range shifts from the region's typically colder waters. Warm water dolphins, like the short-beaked common dolphin and [[striped dolphin]], have expanded north of western Britain and into the northern [[North Sea]], even in the winter, which may displace the [[White-beaked dolphin|white-beaked]] and [[Atlantic white-sided dolphin]] that are in that region. The white-beaked dolphin has shown an increase in the southern North Sea since the 1960s because of this. The [[rough-toothed dolphin]] and [[Atlantic spotted dolphin]] may move to northwest Europe.<ref name="Evans-2013-2"/> In northwest [[Scotland]], white-beaked dolphins (local to the colder waters of the North Atlantic) have decreased while common dolphins (local to warmer waters) have increased from 1992 to 2003.<ref>{{Cite journal |last1=MacLeod |first1=Colin D. |last2=Bannon |first2=Sarah M. |last3=Pierce |first3=Graham J. |last4=Schweder |first4=Caroline |last5=Learmonth |first5=Jennifer A. |last6=Herman |first6=Jerry S. |last7=Reid |first7=Robert J. |date=2005-08-01 |title=Climate change and the cetacean community of north-west Scotland |url=https://www.sciencedirect.com/science/article/abs/pii/S0006320705000789 |journal=Biological Conservation |language=en |volume=124 |issue=4 |pages=477–483 |doi=10.1016/j.biocon.2005.02.004 |bibcode=2005BCons.124..477M |issn=0006-3207}}</ref> Additionally, [[Fraser's dolphin]], found in tropical waters, was recorded in the UK for the first time in 1996.<ref name="Evans-2013-2"/>

[[River dolphin|River dolphins]] are highly affected by climate change as high evaporation rates, increased water temperatures, decreased precipitation, and increased [[Ocean acidification|acidification]] occur.<ref name="Würsig-2001" /><ref name="Gomez-Salazar-2012">{{Cite journal |last1=Gomez-Salazar |first1=Catalina |last2=Coll |first2=Marta |last3=Whitehead |first3=Hal |date=2012-12-01 |title=River dolphins as indicators of ecosystem degradation in large tropical rivers |url=https://www.sciencedirect.com/science/article/abs/pii/S1470160X12000805 |journal=Ecological Indicators |language=en |volume=23 |pages=19–26 |doi=10.1016/j.ecolind.2012.02.034 |bibcode=2012EcInd..23...19G |issn=1470-160X}}</ref> River dolphins typically have a higher densities when rivers have a lox index of freshwater degradation and better water quality. {{Explain|date=April 2025}}<ref name="Gomez-Salazar-2012" /> Specifically looking at the [[Ganges river dolphin]], the high evaporation rates and increased flooding on the plains may lead to more human river regulation, decreasing the dolphin population.<ref name="Würsig-2001" />

As warmer waters lead to a decrease in dolphin prey, this led to other causes of dolphin population decrease. In the case of bottlenose dolphins, [[Mullet (fish)|mullet]] populations decrease due to increasing water temperatures, which leads to a decrease in the dolphins' health and thus their population.<ref name="Würsig-2001" /> At the Shark Bay World Heritage Area in Western Australia, the local [[Indo-Pacific bottlenose dolphin]] population had a significant decline after a marine heatwave in 2011. This heatwave caused a decrease in prey, which led to a decline in dolphin reproductive rates as female dolphins could not get enough nutrients to sustain a calf.<ref>{{Cite journal |last1=Wild |first1=Sonja |last2=Krützen |first2=Michael |last3=Rankin |first3=Robert W. |last4=Hoppitt |first4=William J.E. |last5=Gerber |first5=Livia |last6=Allen |first6=Simon J. |date=2019-04-01 |title=Long-term decline in survival and reproduction of dolphins following a marine heatwave |journal=Current Biology |language=en |volume=29 |issue=7 |pages=R239–R240 |doi=10.1016/j.cub.2019.02.047 |issn=0960-9822 |pmid=30939303 |doi-access=free|bibcode=2019CBio...29.R239W |hdl=1983/1a397eb9-1713-49b5-a2fb-f0d7c747e724 |hdl-access=free }}</ref> The resultant decrease in fish population due to warming waters has also influenced humans to see dolphins as fishing competitors or even bait. Humans use [[Dusky dolphin|dusky dolphins]] as bait or are killed off because they consume the same fish humans eat and sell for profit.<ref name="Würsig-2001" /> In the central Brazilian Amazon alone, approximately 600 [[Pink River Dolphin|pink river dolphins]] are killed each year to be used as bait.<ref name="Gomez-Salazar-2012" />