HISTORICAL AND RECENT COLONIZATION OF THE SOUTH FARALLON ISLANDS, CALIFORNIA, BY NORTHERN FUR SEALS (<i>CALLORHINUS URSINUS</i>)

Pyle, Peter; Long, Douglas J.; Schonewald, Jacqueline; Jones, Robert E.; Roletto, Jan

doi:10.1111/j.1748-7692.2001.tb01282.x

Cited by 16 publications

(8 citation statements)

References 9 publications

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“…The absence of fur seals in the 1998 surveys, therefore, may have been the result of a decline in the total population. Patterns of occurrence of northern fur seals at sea were consistent with sightings of animals hauled out on the South Farallon Islands (Pyle et al 2001).…”

Section: El Niñosupporting

confidence: 50%

“…During autumn, adult female and juvenile northern fur seals migrate from breeding areas in the Bering Sea and the Sea of Okhotsk (Kenyon & Wilke 1953, Kajimura 1980, Pyle et al 2001) to continental slope waters off western North America (Antonelis & Perez 1984, Kajimura 1982. Usually, the greatest numbers off central California occur during February to May (Kajimura 1982).…”

Section: El Niñomentioning

confidence: 99%

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Marine mammal occurrence and ocean climate off central California, 1986 to 1994 and 1997 to 1999

Keiper¹,

Ainley²,

Allen³

et al. 2005

Mar. Ecol. Prog. Ser.

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The California Current System (CCS), a highly variable eastern boundary system, supports a rich marine mammal fauna. Variation in local coastal upwelling, coupled with larger scale processes (El Niño/La Niña) affects the productivity and distribution of marine species at all trophic levels. Herein, we present an analysis of the occurrence patterns of marine mammals in the central CCS and relate these patterns to changing ocean climate and prey availability. Data on marine mammal distributions, ocean conditions, and prey availability were collected in waters overlying the continental shelf and slope from Bodega to Monterey Bays, from 1986 to 1994 and 1997 to 1999. Occurrence patterns were investigated using geographical information system (GIS), percent similarity index (PSI), multiple logistic regression, and principal component analyses. Spatial patterns of the most frequently sighted species (California sea lion Zalophus californianus, northern fur seal Callorhinus ursinus, Pacific white-sided dolphin Lagenorhyncus obliquidens, Dall's porpoise Phocoenoides dalli, harbor porpoise Phocoena phocoena,and humpback whale Megaptera novaeangliae) were related to bathymetry and changing ocean climate, and were likely to have been mediated by changes in prey availability. Temporal changes were related to migration and significant differences in ocean structure resulting from both local and large-scale processes.

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Section: El Niñosupporting

confidence: 50%

Section: El Niñomentioning

confidence: 99%

Marine mammal occurrence and ocean climate off central California, 1986 to 1994 and 1997 to 1999

Keiper¹,

Ainley²,

Allen³

et al. 2005

Mar. Ecol. Prog. Ser.

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“…Our study demonstrates that NFS had more temperate-latitude breeding colonies in the past, with breeding populations in California, the Pacific Northwest (Washington and/or British Columbia), and the eastern Aleutian Islands, and that these populations used a different reproductive strategy than modern populations. Over the past several decades, NFS migrants sourced from high-latitude breeding colonies (Pribilof and Commander Islands, Bering Sea) have reestablished breeding colonies in some of these areas (3,12,13), despite ongoing and unexplained population declines in the source population in the eastern Bering Sea. Further establishment of temperatelatitude breeding colonies could help buffer the global population of this species, through diversification of population and genetic structure, and by diffusing potential threats to population viability (anthropogenic or climatic) over a larger geographical area.…”

Section: Resultsmentioning

confidence: 99%

The shifting baseline of northern fur seal ecology in the northeast Pacific Ocean

Newsome

Etnier

Gifford–Gonzalez³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Historical data provide a baseline against which to judge the significance of recent ecological shifts and guide conservation strategies, especially for species decimated by pre-20th century harvesting. Northern fur seals (NFS; Callorhinus ursinus) are a common pinniped species in archaeological sites from southern California to the Aleutian Islands, yet today they breed almost exclusively on offshore islands at high latitudes. Harvest profiles from archaeological sites contain many unweaned pups, confirming the presence of temperate-latitude breeding colonies in California, the Pacific Northwest, and the eastern Aleutian Islands. Isotopic results suggest that prehistoric NFS fed offshore across their entire range, that California populations were distinct from populations to the north, and that populations breeding at temperate latitudes in the past used a different reproductive strategy than modern populations. The extinction of temperate-latitude breeding populations was asynchronous geographically. In southern California, the Pacific Northwest, and the eastern Aleutians, NFS remained abundant in the archaeological record up to the historical period Ϸ200 years B.P.; thus their regional collapse is plausibly attributed to historical hunting or some other anthropogenic ecosystem disturbance. In contrast, NFS populations in central and northern California collapsed at Ϸ800 years B.P., long before European contact. The relative roles of human hunting versus climatic factors in explaining this ecological shift are unclear, as more paleoclimate information is needed from the coastal zone.Callorhinus ursinus ͉ historic ecology ͉ stable isotopes ͉ zooarchaeology ͉ ancient DNA

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“…Examples of recovery and recolonization of former habitat by pinniped species are widely acknowledged (Bonin et al, ; Cammen et al, ; Grandi et al, ; Hoelzel, Fleischer, Campagna, Le Boeuf, & Alvord, ; Kirkwood, Warneke, & Arnould, ; MacMillan et al, ; Pyle, Long, Shonewald, Jones, & Roletto, ; Reijnders, van Dijk, & Kuiper, ). In addition, temporary migration and the occurrence of transient or visitor animals may have important implications for conservation of the populations and groups of many endangered marine mammals ranging across borders of different countries (Bearzi, Bonizzoni, & Gonzalvo, ; Genov et al, ; Stern, ).…”

Section: Discussionmentioning

confidence: 99%

On sightings of (vagrant?) monk seals, Monachus monachus, in the Mediterranean Basin and their importance for the conservation of the species

Bundone

Panou

Molinaroli

2019

Aquatic Conservation

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In ancient times, the distribution range of the Mediterranean monk seal (Monachus monachus) extended all over the coasts of the Mediterranean, the Black Sea and parts of the north‐eastern Atlantic coast. Nowadays, the species is classified as Endangered and the current total world population is stated to consist of ~700 animals, though numbers mostly express best estimates. Distribution patterns in documents of international authorities from the last 15 years indicate the species' extinction in a number of Mediterranean countries, whereas in some of them only a few individuals are thought to survive and in others the status is unknown. This study analyses recent monk seal sightings over the period from 2000 to 2014 in the Mediterranean Basin. The locations of the sightings cover most of the study area and indicate a spreading of individual seals or a more stable presence in regions where the species was considered extinct. The investigation pointed out that efforts for the protection of monk seals, the most endangered marine mammal in Europe, should encompass all areas where monk seal sightings have been recorded, including the protection and conservation of potential suitable habitats in countries where the species apparently no longer exists. Appropriate conservation measures, such as the establishment of marine protected areas and sustainable management of fisheries, will aid natural recolonization and enhance gene flow between distant regions throughout the Mediterranean Basin, allowing the reconnection of distant populations or individual animals.

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HISTORICAL AND RECENT COLONIZATION OF THE SOUTH FARALLON ISLANDS, CALIFORNIA, BY NORTHERN FUR SEALS (CALLORHINUS URSINUS)

Cited by 16 publications

References 9 publications

Marine mammal occurrence and ocean climate off central California, 1986 to 1994 and 1997 to 1999

Marine mammal occurrence and ocean climate off central California, 1986 to 1994 and 1997 to 1999

The shifting baseline of northern fur seal ecology in the northeast Pacific Ocean

On sightings of (vagrant?) monk seals, Monachus monachus, in the Mediterranean Basin and their importance for the conservation of the species

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