Hauling out

{{Short description|Marine mammal behaviour}}{{Redirect|Haulout|the short documentary|Haulout (film)}}[[File:Sea lion group at haulout.jpg|thumb|right|300px|Sea lion group at haulout]] [[File:Harbor seals at haulout.jpg|thumb|right|250px|Harbor seals at haulout]]

'''Hauling out''' is a behaviour associated with pinnipeds (true seals, sea lions, fur seals and walruses) temporarily leaving the water.<ref name=":Hoelzel" /><ref name=":A" /> Hauling out typically occurs between periods of foraging activity.<ref name=":Hoelzel" /><ref name=":Kovacs" /><ref name=":Gales" /> Rather than remain in the water, pinnipeds haul out onto land or sea ice for reasons such as reproduction and rest.<ref name=":Gales"/><ref name=":A" /> Hauling out is necessary in seals for mating (with the exception of the Baikal seal<ref name=":Hoelzel" />) and giving birth (although a distinction is generally made between reproductive aggregations, termed "rookeries", and non-reproductive aggregations, "haulouts").<ref name=":Gales" /><ref name=":Loughlin" /> Other benefits of hauling out may include predator avoidance, thermoregulation, social activity, parasite reduction and rest.<ref name=":Gales" /><ref name=":A" /><ref name=":Loughlin" /><ref name=":3" />

There is much variation in haul-out patterns among different seal species.<ref name=":Hoelzel">Hoelzel, A. Rus. (2002). ''Marine Mammal Biology: An Evolutionary Approach''. Blackwell Publishing. {{ISBN|978-0-632-05232-5}}. p. 197.</ref> Haul-out sites may be segregated by age and sex within the same species.<ref name=":Kovacs">{{cite journal | last1 = Kovacs | first1 = Kit M. | last2 = Jonas | first2 = Krista M. | last3 = Welke | first3 = Sylvia E. | year = 1990 | title = Sex and age segregation by ''Phoca vitulina concolor'' at haul-out sites during the breeding season in the Passamaquoddy Bay region, New Brunswick | journal = Marine Mammal Science | volume = 6 | issue = 3| pages = 204–214 | doi=10.1111/j.1748-7692.1990.tb00244.x| bibcode = 1990MMamS...6..204K }}</ref> Many species of pinniped have only a few localized rookeries where they breed, but periodically occupy hundreds of haul-out sites throughout the range.<ref name=":Loughlin" /> For example, the Australian fur seals breed on only nine islands in Bass Strait but also occupy up to 50 haul-out sites in south-east Australian waters,<ref name=":Gales">Gales, Nick; Gales, Nicholas; Hindell, Mark; & Kirkwood, Roger. (2003). ''Marine Mammals: Fisheries, Tourism and Management Issues''. CSIRO Publishing. {{ISBN|978-0-643-06953-4}}. p. 259.</ref> and Steller sea lions have around 50 rookeries throughout their range, but several hundred haul-out sites.<ref name=":Loughlin">{{cite journal | last1 = Loughlin | first1 = Thomas R. | last2 = Rugh | first2 = David J. | last3 = Fiscus | first3 = Clifford H. | year = 1984 | title = Northern Sea Lion Distribution and Abundance: 1956-80 | journal = The Journal of Wildlife Management | volume = 48 | issue = 3| pages = 729–740 | doi=10.2307/3801420| jstor = 3801420 }}</ref>

Hauling-out behaviour provides numerous benefits to pinnipeds besides reproduction. This behaviour has been shown to be used for activities such as thermoregulation, predator avoidance, moulting, nursing, and resting.<ref name=":A">{{cite journal|last1=London|first1=Josh M.|last2=Ver Hoef|first2=Jay M.|last3=Jefferies|first3=Steven J.|last4=Lance|first4=Monique M.|last5=Boveng|first5=Peter L.|title=Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Hood Canal, Washington|journal=PLOS ONE|date=June 18, 2012|volume=7|issue=6|article-number=e38180|doi=10.1371/journal.pone.0038180|pmc=3377645|pmid=22723851|bibcode=2012PLoSO...738180L|doi-access=free}}</ref> Haul-out frequency, duration, and site location (i.e. sea-ice, floating-ice, and terrestrial) are all influenced by physical constraints (i.e. air temperature, wind speed, and time of day) and biological constraints (i.e. moulting, age, and sex).<ref name=":A" /><ref name=":1" /><ref name=":3" /><ref name=":4" /><ref name=":7" /> Variations in hauling-out behaviour exist among pinnipeds for reasons such as geographical location.<ref name=":1" />

==Examples== === Weddell seals === [[File:Weddell Seal (js)1.jpg|thumb|Weddell seal on terrestrial haul-out site.]] Haul-out sites of Weddell seals are not necessarily geographically distinct from one another and vary due to physical factors (i.e. food availability) and biological factors (i.e. age).<ref name=":1">{{cite journal|last1=Boeheme|first1=Lars|last2=Baker|first2=Amy|last3=Fedak|first3=Mike|last4=Ârthun|first4=Marius|last5=Nicholls|first5=Keith|last6=Robinson|first6=Patrick|last7=Costa|first7=Dan|last8=Biuw|first8=Martin|last9=Photopoulou|first9=Theoni|title=Bimodal Winter Haul-Out Patterns of Adult Weddell Seals (Leptonychotes weddellii) in the Southern Weddell Sea|journal=PLOS ONE|date=2016|volume=11|issue=5|doi=10.1371/journal.pone.0155817|pmid=27196097|article-number=e0155817|pmc=4873014|bibcode=2016PLoSO..1155817B|doi-access=free}}</ref> Weddell seals are high latitude Antarctic inhabitants, allowing them to haul-out onto ice as adults year round for foraging.<ref name=":1" /> Similar to other pinnipeds, Weddell seals haul-out for reasons such as feeding, rest, avoidance of predators, and thermoregulation.<ref name=":1" /><ref name=":2">{{cite journal|last1=Lake|first1=S.E.|last2=Burton|first2=H.R.|last3=Hindell|first3=M.A.|title=Influence of time of day and month on Weddell seal haul-out patterns at the Vestfold Hills, Antarctica|journal=Polar Biology|date=1997|volume=18|issue=5|pages=319–324|doi=10.1007/s003000050194|bibcode=1997PoBio..18..319L |s2cid=20280920}}</ref> Seasonal variation has been indicated to influence the haul-out patterns of this species, environmental factors such as air temperature and wind speed trigger a shift from long-duration diurnal haul-outs to short-duration nocturnal patterns.<ref name=":1" /> Following moulting season the number of haul-outs performed increases allowing the seals to benefit from the increased air temperature and thus decreasing the energetic cost of growing new hair.<ref name=":1" /><ref name=":2" /> The haul-out patterns of female Weddell seal are heavily influenced by the age of their pups.<ref name=":2" /><ref name=":3">{{cite journal|last1=Thomas|first1=Jeanette|last2=DeMaster|first2=Douglas|title=Diel haul-out patterns of Weddell seal (Leptonychotes weddelli) females and their pups|journal=Canadian Journal of Zoology|date=1983|volume=61|issue=9|pages=2084–2086|doi=10.1139/z83-273|bibcode=1983CaJZ...61.2084T }}</ref> In the first week post parturition, haul-out frequency is high and females remain hauled-out for longer periods prior to the pups starting to swim. Haul-out frequency decreases as the pups are weaned and mating begins.<ref name=":1" /><ref name=":2" /><ref name=":3" />

===Walruses=== [[File:Noaa-walrus9.jpg|thumb|Group of walruses on sea-ice haul-out.]] Walruses tend to occupy both terrestrial and sea ice haul-out sites, alternating between the two depending on resource availability.<ref name=":4">{{cite journal|last1=Udevitz|first1=Mark|last2=Chadwick|first2=Jay|last3=Fischbach|first3=Anthony|last4=Garlich-Miller|first4=Joel|title=Modeling haul-out behavior of walruses in Bering Sea ice|journal=Canadian Journal of Zoology|date=2009|volume=87|issue=12|pages=1111–1128|doi=10.1139/Z09-098|bibcode=2009CaJZ...87.1111U }}</ref> Walruses haul-out onto land primarily for birthing, moulting, nursing, and resting, meanwhile using sea-ice haul-out sites for foraging and predator avoidance.<ref name=":4" /><ref name=":5" /> These physiological factors are correlated with both the duration and frequency of haul-outs among walruses.<ref name=":4" /> Sea ice sites are more commonly used for shorter and more frequent haul-outs compared to terrestrial sites, which are commonly used to fulfill more time-consuming requirements (i.e. breeding and birthing).<ref name=":4" /><ref name=":5" /> Hauling out is also used as a method of thermoregulation, therefore it is influenced by various environmental factors such as wind speed, temperature, and even time of day.<ref name=":4" /> Accounting for these environmental factors, walruses more frequently haul-out from late morning to early evening and avoid hauling out during weather periods of intense cold or high winds.<ref name=":4" /><ref name=":5" /> Haul-out frequency is at a maximum for walruses during the summer using terrestrial haul-out sites as sea ice sites are then further from foraging grounds.<ref name=":4" /><ref name=":5" /> As female walruses haul-out for parturition, the males are territorial of the haul-out site surrounding the female herd.<ref name=":5">{{cite journal|last1=Hamilton|first1=Charmain|last2=Kovacs|first2=Kit|last3=Lydersen|first3=Christian|title=Year-round haul-out behaviour of male walruses Odobenus rosmarus in the Northern Barents Sea|journal=Marine Ecology Progress Series|date=2015|volume=519|pages=251–263|doi=10.3354/meps11089|bibcode=2015MEPS..519..251H|doi-access=free}}</ref> In these instances, hauling out provides an opportunity for more aggressive and territorial males to mate.<ref name=":6">{{cite journal|last1=Charrier|first1=Isabelle|last2=Burlet|first2=Armandine|last3=Aubin|first3=Thierry|title=Social vocal communication in captive Pacific walruses Odobenus rosmarus divergens|journal=Mammalian Biology|volume=76|issue=5|pages=622–627|doi=10.1016/j.mambio.2010.10.006|year=2011|bibcode=2011MamBi..76..622C }}</ref>

===Ringed seal=== [[File:Pusa hispida hispida NOAA 1.jpg|thumb|Ringed seal on sea-ice haulout]] Ringed seal haulouts occur throughout any point in the year, however it reaches a maximum during the spring.<ref name=":7">{{cite journal|last1=Born|first1=E. W.|last2=Teilmann|first2=J.|last3=Riget|first3=F.|title=Haul-out activity of Ringed seals (Phoca hispida) determined form satellite telemetry|journal=Marine Mammal Science|date=2002|volume=18|issue=1|pages=167–181|doi=10.1111/j.1748-7692.2002.tb01026.x|bibcode=2002MMamS..18..167B }}</ref> In comparison to other pinniped species, ringed seals haul-out with a shorter duration year round.<ref name=":7" /> Ringed seals have a diel haul-out pattern in which they spend more time hauled-out during the night, an uncommon feature among pinnipeds.<ref name=":7" /><ref name=":10">{{cite journal|last1=Smith|first1=T. G.|title=Population dynamics of the ringed seal in the Canadian eastern Arctic|journal=Fisheries Research Board of Canada Bulletin|volume=181|page=55}}</ref> Hauling out spikes an increase in the herding behaviour of ringed seals, particularly in the Ladoga subspecies.<ref name=":8">{{cite journal|last1=Sipilä|first1=Tero|last2=Medvedev|first2=Nikolai|last3=Hyvärinen|first3=Heikki|title=The Ladoga seal (Phoca hispida ladogensis Nordq.)|journal=Hydrobiologia|date=1996|volume=322|issue=1–3|pages=193–198|doi=10.1007/bf00031827|bibcode=1996HyBio.322..193S |s2cid=26024676}}</ref> Subspecies of the ringed seal prefer different haul-out sites depending on their geographical location and environmental constraints.<ref name=":9">{{cite journal|last1=Smith|first1=Thomas|last2=Stirling|first2=Ian|title=The breeding habitat of the ringed seal (Phoca hispida). The birth lair and associated structures|journal=Canadian Journal of Zoology|date=1975|volume=53|issue=9|pages=1297–1305|doi=10.1139/z75-155|bibcode=1975CaJZ...53.1297S }}</ref> For example, 5 subspecies of ringed seals prefer hauling out onto land-fast ice, however ''Phoca hispida ochotensis'' prefers drifting pack ice, meanwhile ''Phoca hispida hispida'' occupies both land-fast ice and far offshore areas of relatively stable ice.<ref name=":9" /> The majority of ringed seals however use terrestrial haul-out sites to create birth layers in the snow for newborn seal pups.<ref name=":9" />

===Harbour seal=== [[File:Harbor seal rocks.jpg|thumb|Harbour seals on intertidal site]] Harbour seals are the most abundant pinniped in the eastern North Pacific Ocean.<ref name=":A" /> Much like other pinnipeds, harbour seals haul-out for reasons such as thermoregulation, breeding, mating, moulting, resting, and foraging.<ref name=":11" /><ref name=":A" /> They commonly haul-out onto intertidal ledges, mudflats, beaches, and ice floes year round.<ref name=":11">{{cite journal|last1=Terhune|first1=John|title=Meteorological influences on harbour seal haul-out|journal=Aquatic Mammals|date=1987|volume=13|issue=3|pages=114–118}}</ref> Haulout sites are often revisited on a regular basis by the same herd<ref name=":A" /> and are heavily affected by tide height.<ref name=":A" /><ref name=":11" /> Harbour seals are likely to move haul-out sites in response to inclement weather conditions (i.e. wind chill and wave size) to more favourable sites in rocky reefs, mudflats, and beaches that are exposed during lower tides.<ref name=":A" /><ref name=":11" />

Frequency and duration of the behaviour is at a maxima during early afternoon when lower tides and higher air temperatures are prevalent.<ref name=":A" /><ref name=":11" /> During parturition and weaning, females spend more time hauled-out ashore until their pups begin to swim, meanwhile males spend less time hauled-out and maintain aquatic territories instead.<ref name=":A" /> Moulting and predation risk also increase the time spent hauled-out.<ref name=":A" /> Despite the increased time ashore for females and decreased time ashore or males during birthing and weaning, biological constraints such as age and sex have not been shown to effect harbour seal haul-outs.<ref name=":A" /> Both male and female harbour seals of all ages are consistent with time spent hauled-out.<ref name=":A" /><ref name=":11" /> Harbour seals commonly inhabit regions susceptible to human disturbances (i.e. industries such as the fishery), a factor that has been studied and shown to alter haul-out patterns.<ref name=":12">{{cite journal|last1=Härkönen|first1=T. J.|title=Influence of feeding on haul-out patterns and sizes of sub-populations in harbour seals|journal=Netherlands Journal of Sea Research|date=1987|volume=21|issue=4|pages=331–339|doi=10.1016/0077-7579(87)90007-x|bibcode=1987NJSR...21..331H}}</ref> Human disturbances negatively influence the duration and frequency of harbour seal haul-outs, decreasing the occurrence of this behaviour as human interference increases.<ref name=":12" />

==References== {{reflist}}

Category:Pinnipeds Category:Ethology