Editing Northern elephant seal (section)

==History and status==
[[File:Breeding colony of Mirounga angustirostris.jpg|thumb|left|The northern elephant seal population was estimated to be 171,000 in 2005.<ref name="iucn status 12 November 2021" />]]
Beginning in the 18th century, northern elephant seals were hunted extensively, almost to extinction by the end of the 19th century, being prized for oil made from their [[blubber]], and the population may have fallen as low as only 20–40 individuals.<ref name="iucn status 12 November 2021" /> In 1874, [[Charles Melville Scammon]] recorded in ''Marine Mammals of the Northwestern Coast of America'', that an {{convert|18|ft|adj=on}} long bull caught on [[Santa Barbara Island]] yielded {{convert|210|usgal|0}} of oil.<ref>{{cite book |title=The marine mammals of the northwestern coast of North America: together with an account of the American whale-fishery |page=132 |url=https://books.google.com/books?id=GJ1tlnhkTWcC |last=Scammon |first=Charles Melville |name-list-style=vanc |publisher=[[Heyday Books]] |year=2007 |isbn=978-1-59714-061-4 }}</ref> They were thought to be extinct in 1884 until a remnant population of eight individuals was discovered on [[Guadalupe Island]] in 1892 by a [[Smithsonian Institution|Smithsonian]] expedition, who promptly killed several for their collections.<ref>{{cite book |title=The War Against the Seals: A History of the North American Seal Fishery | last = Busch | first = Briton Cooper | name-list-style = vanc |page=187 |url=https://books.google.com/books?id=Q4WF3PTh4kQC&pg=PA187 |publisher=McGill-Queen's Press |year=1987 |isbn=978-0-7735-0610-7 }}</ref> The elephant seals managed to survive, and were finally protected by the Mexican government in 1922. Since the early 20th century, they have been protected by law in both Mexico and in the United States. Subsequently, the U.S. protection was strengthened after passage of the [[Marine Mammal Protection Act of 1972]], and numbers have now recovered to over 200,000.<ref>{{Cite journal |last=Lowry |first=Mark S. |last2=Jaime |first2=Elizabeth M. |last3=Nehasil |first3=Stephanie E. |last4=Betcher |first4=Amy E. |last5=Condit |first5=Richard |title=Winter surveys at the Channel Islands and Point Conception reveal population growth of northern elephant seals and residence counts of other pinnipeds |url=https://repository.library.noaa.gov/view/noaa/25229 |journal=NOAA Technical Memorandum NMFS |language=en |issue=627 |doi=10.25923/k8c2-a111}}</ref><ref>{{Cite journal |last=Lowry |first=Mark |date=2014-03-01 |title=Abundance, Distribution, and Population Growth of the Northern Elephant Seal (Mirounga angustirostris) in the United States from 1991 to 2010 |url=https://www.aquaticmammalsjournal.org/article/vol-40-iss-1-lowry/ |journal=Aquatic Mammals |volume=40 |issue=1 |pages=20–31 |doi=10.1578/AM.40.1.2014.20|url-access=subscription }}</ref>

Nevertheless, a [[genetic bottleneck]] experienced by northern elephant seals during the nineteenth century made them more susceptible to disease, environmental changes and pollution.<ref>{{cite journal |vauthors=Hoelzel AR, Fleischer R, Campagna C, Le Boeuf BJ, Alvord G |year=2002 |title=Impact of a population bottleneck on symmetry and genetic diversity in the northern elephant seal |journal=Journal of Evolutionary Biology |volume=15 |pages=567–575 |doi=10.1046/j.1420-9101.2002.00419.x |issue=4 |s2cid=85821330 |doi-access=}}</ref><ref>{{cite journal |vauthors=Weber DS, Stewart BS, Garza JC, Lehman N |title=An empirical genetic assessment of the severity of the northern elephant seal population bottleneck |journal=Current Biology |volume=10 |issue=20 |pages=1287–90 |date=October 2000 |pmid=11069110 |doi=10.1016/S0960-9822(00)00759-4 |s2cid=14943019 |name-list-style=amp |doi-access=free |bibcode=2000CBio...10.1287W }}</ref> Such a small initial population of around 20–40 also meant that extensive inbreeding occurred within the species, leading to a whole other onset of issues.<ref name="HOELZEL 23–39">{{Cite journal |last=HOELZEL |first=A. RUS |date=September 1999 |title=Impact of population bottlenecks on genetic variation and the importance of life-history; a case study of the northern elephant seal |journal=Biological Journal of the Linnean Society |volume=68 |issue=1–2 |pages=23–39 |doi=10.1111/j.1095-8312.1999.tb01156.x |issn=0024-4066|doi-access=free }}</ref> Such issues from the bottleneck a sharp loss of [[genetic diversity]] and increased [[homozygosity]] in the surviving population, and also a decreased number of [[haplogroup]]s.<ref>{{cite book |first1=Richard |last1=Frankham |first2=Jonathan D. |last2=Ballou |first3=David Anthony |last3=Briscoe |first4=Karina H |last4=McInness |name-list-style=vanc |title=Introduction to Conservation Genetics |publisher=Cambridge Cambridge University Press |year=2013 |edition=2nd |isbn=978-0-521-87847-0 |url=https://books.google.com/books?id=vLZKnsCk89wC&pg=PA169 }}</ref> In addition to this, there was also a substantial increase in the rate of asymmetry within the animals' skulls.<ref name="HOELZEL 23–39"/>
[[File:Northern elephant seal sleeping.PNG|thumb|A northern elephant seal sleeps on the coast of the [[Channel Islands National Marine Sanctuary]] in&nbsp;[[California]].]]
In California, the population is continuing to grow at around 6% per year, and new colonies are being established; they are now probably limited mostly by the availability of [[hauling-out|haul-out]] space. Their breeding was probably restricted to islands, before large carnivores were exterminated or prevented from reaching the side of the ocean.<ref>{{cite book |chapter=Ch. 7 "Mammals" |title=The Natural History of Ano Nuevo |year=1981 |editor=Le Boeuf, Burney J. |editor2=Kaza, Stephanie |publisher=Boxwood Press |isbn=978-0910286770 |chapter-url=https://archive.org/details/environmentaleth00shra |url-access=registration |url=https://archive.org/details/environmentaleth00shra}}</ref> Numbers can be adversely affected by [[El Niño]] events and the resultant weather conditions, and the 1997–98 El Niño may have caused the loss of about 80% of that year's pups. Presently, the northern elephant seal is protected under the federal Marine Mammal Protection Act and has a fully protected status under California law (California Fish and Game Code [FGC] § 4700).

While the population is rising in the state of California, some colonies farther south are experiencing declining populations, likely due to rising sea and air temperatures. In Baja California, the two largest colonies, in Guadalupe and San Benito, have seen consistently declining numbers for the past two decades. Seeing as populations farther north are consistently increasing, it has been hypothesized that this discrepancy is due to a change in migration patterns.<ref name=":1">{{Cite journal |last1=García-Aguilar |first1=María C. |last2=Turrent |first2=Cuauhtémoc |last3=Elorriaga-Verplancken |first3=Fernando R. |last4=Arias-Del-Razo |first4=Alejandro |last5=Schramm |first5=Yolanda |date=2018-02-15 |title=Climate change and the northern elephant seal (Mirounga angustirostris) population in Baja California, Mexico |journal=PLOS ONE |language=en |volume=13 |issue=2 |pages=e0193211 |doi=10.1371/journal.pone.0193211 |issn=1932-6203 |pmc=5814045 |pmid=29447288|bibcode=2018PLoSO..1393211G |doi-access=free }}</ref> As sea and air temperatures rise, Northern elephant seals may not be migrating as far south as they have previously. The climate is expected to continue warming, and southern populations are expected to continue falling.<ref name=":1" />

Populations of rookery sites in California have increased during the past century.<ref name="iucn status 12 November 2021" /> At [[Año Nuevo State Park]], for example, no individuals were observed whatsoever until 1955; the first pup born there was observed in the early 1960s. Currently, thousands of pups are born every year at Año Nuevo, on both the island and mainland. The growth of the site near San Simeon has proved even more spectacular; no animals were there prior to 1990. Currently, the San Simeon site hosts more breeding animals than Año Nuevo State Park during winter season.{{citation needed|date = October 2017}}