Diferenzas entre revisións de «Erignathus barbatus»

Underwater, bearded seal trills can be heard from a distance of over 30&nbsp;km, with some types of sounds traveling farther than others. This makes it possible for one animal to communicate with another animal that is far away, although acoustic degradation does occur as the sound passes through the environment. A seal must produce a trill with a [[Sound pressure|sound-pressure]] of at least 100 [[Decibel|dB]] at 1 m in order for the sound to propagate 30&nbsp;km, meaning that bearded seals can likely produce sounds at this level.<ref name=":1" />[[Image:beardedseal2.jpg|thumb|Bearded seal on ice, [[Svalbard]]]]
==Conservation status==
On March 28, 2008, the U.S. [[National Marine Fisheries Service]] initiated a status review<ref>[http://www.nmfs.noaa.gov/pr/pdfs/fr/fr73-16617-ribbonseal.pdf Federal Register /Vol. 73, No. 61 / March 28, 2008 / Proposed Rules]. National Marine Fisheries Service</ref> under the [[Endangered Species Act]] (ESA) to determine if listing this species under the ESA is warranted. All bearded seals are protected under the [[Marine Mammal Protection Act]], and determined by the [[International Union for Conservation of Nature|IUCN]] to be classified as a "least concern" for extinction.<ref>{{Cite web|url=http://oldredlist.iucnredlist.org/details/8010/0|title=Erignathus barbatus (Bearded Seal)|website=www.iucnredlist.org|access-date=2018-06-06}}</ref> This classification was determined due to various factors including, widespread distribution, stable population size, as well as alternating prey resources. [[National Oceanic and Atmospheric Administration|NOAA]] determined that the factors influencing any change in conservancy status of the bearded seal may include: loss of sea ice by climate change, [[bycatch]] from commercial fishing gear, and hunting.<ref>{{Cite web|url=https://www.fisheries.noaa.gov/species/bearded-seal|title=Bearded Seal {{!}} NOAA Fisheries|last=Fisheries|first=NOAA|date=2018-05-24|website=www.fisheries.noaa.gov|language=EN-US|access-date=2018-06-06}}</ref> Their main predators include [[polar bear]]s, however, typically pups around age 2 are attacked within birthing lairs, leaving older juveniles and adults commonly unharmed.<ref>{{Cite journal|title=Canadian Science Publishing|url=http://www.nrcresearchpress.com/doi/abs/10.1139/z80-302#.Ww96nkgvzIU|doi=10.1139/z80-302#.ww96nkgvziu|doi-broken-date=2019-03-13}}</ref> Due to climate change, factors such as loss of sea ice, as well as decrease in prey population may create negative results on the bearded seal population in the future. Therefore, monitoring of the species as well as influences of human activity, will be vital to ensure species stability.
== Status de conservación ==
A [[IUCN]] clasifica esta especie como en situación "pouco preocupante".<ref>{{Cite web|url=http://oldredlist.iucnredlist.org/details/8010/0|title=Erignathus barbatus (Bearded Seal)|website=www.iucnredlist.org|access-date=2018-06-06}}</ref> Esta clasificación está determinada por varios factores como a súa ampla distribución, tamaño de poboación estable, e recursos de posibles presas alternativos. A [[NOAA]] determinou que os factores que inflúen en calquera posible cambio no status de conservación da foca barbuda poden ser: perda de xeo mariño por mor do cambio climático, pesca accidental (''bycatch'') en aparellos de pesca comerciais e a caza.<ref>{{Cite web|url=https://www.fisheries.noaa.gov/species/bearded-seal|title=Bearded Seal {{!}} NOAA Fisheries|last=Fisheries|first=NOAA|date=2018-05-24|website=www.fisheries.noaa.gov|language=EN-US|access-date=2018-06-06}}</ref> Os seus principais depredadores son os osos polares.<ref>{{Cite journal|title=Canadian Science Publishing|url=http://www.nrcresearchpress.com/doi/abs/10.1139/z80-302#.Ww96nkgvzIU|doi=10.1139/z80-302#.ww96nkgvziu|doi-broken-date=2019-03-13}}</ref> Debido ao cambio climático, os factores como a perda de xeo mariño ou a diminución das poboacións de presas poden producir resultados negativos sobre as poboacións da foca barbuda no futuro. Por tanto, a monitorización da especie e as influencias das actividades humanas serán vitais para asegurar a estabilidade da especie.
== Subespecies ==
Recoñécense dúas subespecies:<ref name=msw3/>