Life History of the Sea-Lions on the California Coast

Rowley, J.C.

doi:10.2307/1374097

Cited by 21 publications

(17 citation statements)

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“…In the Leipzig Zoo they entered the water for the first time at the age of 18 days and according to Allen (1880) pups do not swim before they are 4-5 weeks old. Rowley (1929) says that the newborns cannot swim. If they are brought into the water they float by heavy leaps of their flippers.…”

Section: -The Closure Of the Ductus In Aquatic Mammalsmentioning

confidence: 99%

Foramen Ovale and Ductus Arteriosus Botalli in Aquatic Mammals

Slijper¹

1961

Mammalia

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ment.retardée pâr râpport aux animaux terrestres. ces faits rotrt en rapport avec la t-ension en oxygène-du sâng.-L,élévation de celle_ci ap"ès ia orir.ao"e entraine I'occlusion du canal ; une ãéficience en oxygèn" "ri àî "ã"^i"J"" "ap^_ ble de ìtouvrir à nouveau. L'auteur examine la bio"rogie a", ",,i-u"" marins en fonction de ces diverses données et compare notamrnent les cétacés et re Phoque veau-marin aux a-utres pinnipèdes, dont res ¡"""", ,r"-p¿rr¿t""nt dans I'eau qu'âgés de 3-4 semaines au moins et parfois plüs.

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Section: -The Closure Of the Ductus In Aquatic Mammalsmentioning

confidence: 99%

Foramen Ovale and Ductus Arteriosus Botalli in Aquatic Mammals

Slijper¹

1961

Mammalia

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“…, Bradshaw et al 2000), however colonization of new rookeries by Steller sea lions is not common. From at least the 1920s into the 1980s, the Forrester Island complex (54°48′10″N, 133°31′37″W) was the only Steller sea lion rookery in southeastern Alaska (Rowley 1929, Pitcher et al . 2007).…”

mentioning

confidence: 99%

Population growth and colonization of Steller sea lions in the Glacier Bay region of southeastern Alaska: 1970s–2009

Mathews

Womble

Pendleton

et al. 2011

Marine Mammal Science

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We estimated trends in numbers of Steller sea lions in the Glacier Bay region of the eastern population from the 1970s to 2009. We documented the colonization of several new haul‐outs and the transition of one haul‐out (Graves Rocks) to a rookery, assessed seasonal patterns in distribution, and compared counts from different observation platforms. Sea lions increased in the region by 8.2%/yr (95%CI = 6.4%–10.0%), with the most growth at South Marble Island in Glacier Bay (16.6%/yr, 1991–2009) and rapid growth in Cross Sound. Seasonal patterns in the distribution of sea lions were likely influenced by new breeding opportunities and the seasonal availability of prey. Factors that likely contributed to the exceptional growth include availability of new habitat following deglaciation, immigration, redistribution, decreases in mortality, and ecosystem‐level changes. The rapid increase in sea lion numbers in this region is of particular interest in light of dramatic declines in the western population and evidence that Steller sea lions from both the eastern and western populations colonized the Graves Rocks rookery. The colonization and rookery development in this dynamic area may signal the reversal of the reproductive isolation of the two populations.

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“…). The primary breeding ranges were even further apart as pup counts were low on peripheral rookeries in both populations for much of this time (Rowley ; Mathisen & Lopp ; Calkins & Pitcher ). The emergence of Forrester as a major rookery mid‐century followed by the colonization of Hazy Island, White Sisters and Graves Rocks by the late 1990s closed the gap to 630 km.…”

Section: Discussionmentioning

confidence: 99%

“…). East of 144°W, exponential growth in southeast Alaska has been accompanied by the sequential colonization of new breeding sites north of Forrester Island, the only rookery in southeast Alaska for most of the 20th century (Rowley ; Trites & Larkin ; Pitcher et al . ).…”

Section: Introductionmentioning

confidence: 99%

Crossing to safety: dispersal, colonization and mate choice in evolutionarily distinct populations ofSteller sea lions,Eumetopias jubatus

et al. 2014

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Population growth typically involves range expansion and establishment of new breeding sites, while the opposite occurs during declines. Although density dependence is widely invoked in theoretical studies of emigration and colonization in expanding populations, few empirical studies have documented the mechanisms. Still fewer have documented the direction and mechanisms of individual transfer in declining populations. Here, we screen large numbers of pups sampled on their natal rookeries for variation in mtDNA (n = 1106) and 16 microsatellite loci (n = 588) and show that new Steller sea lion breeding sites did not follow the typical paradigm and were instead colonized by sea lions from both a declining (Endangered) population and an increasing population. Dispersing individuals colonized rookeries in the distributional hiatus between two evolutionarily distinct (Φ¯(st) = 0.222, R¯(st) = 0.053, K = 2) metapopulations recently described as separate subspecies. Hardy-Weinberg, mixed-stock and relatedness analysis revealed levels of interbreeding on the new rookeries that exclude (i) assortative mating among eastern and western forms, and (ii) inbreeding avoidance as primary motivations for dispersal. Positive and negative density dependence is implicated in both cases of individual transfer. Migration distance limits, and conspecific attraction and performance likely influenced the sequence of rookery colonizations. This study demonstrates that resource limitation may trigger an exodus of breeding animals from declining populations, with substantial impacts on distribution and patterns of genetic variation. It also revealed that this event is rare because colonists dispersed across an evolutionary boundary, suggesting that the causative factors behind recent declines are unusual or of larger magnitude than normally occur.

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Life History of the Sea-Lions on the California Coast

Cited by 21 publications

References 0 publications

Foramen Ovale and Ductus Arteriosus Botalli in Aquatic Mammals

Foramen Ovale and Ductus Arteriosus Botalli in Aquatic Mammals

Population growth and colonization of Steller sea lions in the Glacier Bay region of southeastern Alaska: 1970s–2009

Crossing to safety: dispersal, colonization and mate choice in evolutionarily distinct populations ofSteller sea lions,Eumetopias jubatus

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