Occurrence of leopard seals in northern Argentina

Rodríguez, Diego H.; Bastida, Ricardo; Morón, Sergio; Heredia, Sergio Rodríguez; Loureiro, João

doi:10.5597/lajam00031

Cited by 16 publications

(11 citation statements)

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“…The leopard seals encountered during this study (n = 77) were not sexually dimorphic, and, as has been previously reported by Walker et al (1998) and Rodriguez et al (2003), the seals' body condition diminished when they were seen at subtropical latitudes. We developed a subjective visual index, validated against 2 empirical indices (the Smirnov condition index and the Fineness Ratio), to determine the body condition for these vagrant seals; the visual index can delineate poor condition seals from others.…”

Section: Discussionsupporting

confidence: 84%

“…Based on their emaciated appearance, lethargy and open wounds on various body regions, vagrant leopard seals (i.e. seasonal visitors seen far to the north of their typical Antarctic habitat) are often assessed to have "poor" body condition (Rodriguez et al 2003). Vagrant seals are most often seen in the lower latitudes during winter when the Antarctic sea-ice has reached its maximum extent (Hamilton 1939, Best 1971, where assessment of their condition can be misleading to the inexperienced observer because leopard seals are lean for their length, and leaner than other phocids such as the southern elephant seal (Duignan 2003).…”

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confidence: 99%

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Estimating Body Mass and Condition of Leopard Seals by Allometrics

Hoff¹,

Fraccaro²,

Mitchell³

et al. 2005

Journal of Wildlife Management

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Leopard seals (Hydrurga leptonyx) are formidable marine predators and require sedation before scientific examination. Mass‐specific drug dosage for leopard seals has usually been determined from generic allometric equations or visual estimates. However, the leopard seal is a slender phocid and generic equations are likely to return inaccurate mass estimates, which may lead to fatal overdoses of drugs. We used published and unpublished morphometric data to construct allometric models for estimating leopard seal body mass. The model using volume (Vol), which combined measures of snout‐tail length (STL) and the square of girth (G2), provided our best estimate of mass (r2 = 0.97). The model using STL alone was sample‐site specific (each r2 ≥ 0.85), highlighting G as an important measure to obtain where possible. The confidence and prediction intervals associated with each model broadened with increased seal size and decreased sample size, suggesting the use of extra caution when estimating drug dosage for larger seals to avoid over‐ or under‐dosing. We also developed a seal body condition index that can assist wildlife management when deciding if rehabilitation of vagrant seals is warranted. Body condition may also affect the induction, duration and recovery times of anaesthetized leopard seals.

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Section: Discussionsupporting

confidence: 84%

mentioning

confidence: 99%

Estimating Body Mass and Condition of Leopard Seals by Allometrics

Hoff¹,

Fraccaro²,

Mitchell³

et al. 2005

Journal of Wildlife Management

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“…They are most commonly found in and around the outer fringes of the pack ice or close to the Antarctic Continent [ 9 – 11 ]. Their range extends beyond the Polar Front with regular sightings in South America [ 12 , 13 ], and individuals reported in South Africa [ 14 ], Australia [ 15 ] and as far north as the Cook Islands [ 14 ]. Across this north-south distribution there is evidence of a gradient in age classes with the proportion of younger immature animals increasing in lower latitudes [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Long term movements and activity patterns of an Antarctic marine apex predator: The leopard seal

et al. 2018

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Leopard seals are an important Antarctic apex predator that can affect marine ecosystems through local predation. Here we report on the successful use of micro geolocation logging sensor tags to track the movements, and activity, of four leopard seals for trips of between 142–446 days including one individual in two separate years. Whilst the sample size is small the results represent an advance in our limited knowledge of leopard seals. We show the longest periods of tracking of leopard seals’ migratory behaviour between the pack ice, close to the Antarctic continent, and the sub-Antarctic island of South Georgia. It appears that these tracked animals migrate in a directed manner towards Bird Island and, during their residency, use this as a central place for foraging trips as well as exploiting the local penguin and seal populations. Movements to the South Orkney Islands were also recorded, similar to those observed in other predators in the region including the krill fishery. Analysis of habitat associations, taking into account location errors, indicated the tracked seals had an affinity for shallow shelf water and regions of sea ice. Wet and dry sensors revealed that seals hauled out for between 22 and 31% of the time with maximum of 74 hours and a median of between 9 and 11 hours. The longest period a seal remained in the water was between 13 and 25 days. Fitting GAMMs showed that haul out rates changed throughout the year with the highest values occurring during the summer which has implications for visual surveys. Peak haul out occurred around midday for the months between October and April but was more evenly spread across the day between May and September. The seals’ movements between, and behaviour within, areas important to breeding populations of birds and other seals, coupled with the dynamics of the region’s fisheries, shows an understanding of leopard seal ecology is vital in the management of the Southern Ocean resources.

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“…Para Argentina existen registros de la foca leopardo (H. leptonyx) en las provincias de Buenos Aires, Chubut y Río Negro (Castello & Rumboll, 1978;Rodríguez et al, 2003;Daneri et al, 2011). La foca de Weddell (Leptonychotes weddellii) se ha reportado en las provincias de Santa Cruz y Tierra del Fuego (Stirling, 1971;Rice, 1998).…”

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Ocurrencia De Focas (Mammalia, Carnivora, Phocidae) en Uruguay

Juri¹

2017

BolSZU

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RESUMENSe presenta una revisión actualizada sobre la ocurrencia de fócidos para Uruguay (1921Uruguay ( -2016. Se obtuvieron 64 registros que ocurrieron en la costa Atlántica (n=45), Río de la Plata (n=13) y en otros ríos y arroyos (n=6). Se reclasificaron especímenes erróneamente identificados, además se encontraron especímenes perdidos y se presentan 21 registros de fócidos no publicados.Palabas clave: Focas, Phocidae, Registros, Uruguay ABSTRACTOccurrence of seals (Mammalia, Carnivora, Phocidae) in Uruguay. An updated review on the occurrence of seals for Uruguay (1921Uruguay ( -2016 is presented. A total of 64 records occurred on the Atlantic coast (n=45), Rio de la Plata (n=13) and other rivers and streams (n=6). Erroneously identified specimens were reclassified, missing specimens were found and 21 unpublished seals records are presented.

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Occurrence of leopard seals in northern Argentina

Cited by 16 publications

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Estimating Body Mass and Condition of Leopard Seals by Allometrics

Estimating Body Mass and Condition of Leopard Seals by Allometrics

Long term movements and activity patterns of an Antarctic marine apex predator: The leopard seal

Ocurrencia De Focas (Mammalia, Carnivora, Phocidae) en Uruguay

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