Estimating population status under conditions of uncertainty: the Ross seal in East Antarctica

  title={Estimating population status under conditions of uncertainty: the Ross seal in East Antarctica},
  author={Colin Southwell and Charles G. M. Paxton and David L. Borchers and Peter L. Boveng and Erling S. Nord{\o}y and Arnoldus Schytte Blix and William de la Mare},
  journal={Antarctic Science},
  pages={123 - 133}
Abstract The Ross seal (Ommatophoca rossii) is the least studied of the Antarctic ice-breeding phocids. In particular, estimating the population status of the Ross seal has proved extremely difficult. The Protocol on Environmental Protection to the Antarctic Treaty currently designates the Ross seal as a ‘Specially Protected Species’, contrasting with the IUCN's classification of ‘Least Concern’. As part of a review of the Ross seal's classification under the Protocol, a survey was undertaken… 

Distribution, density and abundance of Antarctic ice seals off Queen Maud Land and the eastern Weddell Sea

The Atlantic sector of the Southern Ocean (the easternsector of the Weddell Sea) was surveyed by research teams from Germany, Norway and South Africa using a range of aerial methods over five austral summers between 1996–1997 and 2000–2001, providing an important baseline against which to compare future changes in seal distribution and abundance.

Erratum to: Distribution, density and abundance of Antarctic ice seals off Queen Maud Land and the eastern Weddell Sea

The Antarctic Pack Ice Seal (APIS) Program was initiated in 1994 to estimate the abundance of four species of Antarctic phocids: the crabeater seal Lobodon carcinophaga, Weddell seal Leptonychotes

Limited use of sea ice by the Ross seal (Ommatophoca rossii), in Amundsen Sea, Antarctica, using telemetry and remote sensing data

Their pelagic behaviour suggests that Ross seals, although being an ice obligate species, may adapt comparatively easy to climate change involving ice melting and recession and thereby potentially being less sensitive to the reduction of sea ice than other Antarctic seal species.

Antarctic pack ice seal observations during spring across the Lazarev Sea

Abstract The distribution, density and percentage contribution of pack ice seals during ship-board censuses in the marginal sea ice zone beyond the Lazarev Sea in spring 2019 are presented.

Responses of Antarctic pack-ice seals to environmental change and increasing krill fishing

Haul-out behavior and aerial survey detectability of seals in the Bering and Chukchi seas

Ice-associated seals rely on sea ice for a variety of activities, including breeding, molting, pupping, and resting. In the Arctic, many of these activities occur in spring (April – June) as sea ice

Genetically effective population sizes of Antarctic seals estimated from nuclear genes

Microsatellite NE estimates were comparable with previously published NE estimates from mitochondrial DNA, but both are substantially lower than direct estimates of population size in all species except the Ross seals.



Haul-out behaviour of two Ross seals off eastern Antarctica

  • C. Southwell
  • Environmental Science, Geology
    Antarctic Science
  • 2003
Accurate assessment of the abundance of pinnipeds from visual surveys requires estimation of both the available (hauled-out) and unavailable (in-water) components of the population (Eberhardt et al.

Optimising the timing of visual surveys of crabeater seal abundance: haulout behaviour as a consideration

Satellite-linked dive recorders were attached to 24 adult seals in the pack-ice off east Antarctica to record haulout behaviour over a 4-month period from mid-September to mid-January to assess the optimal time for conducting visual surveys of crabeater seals.

Seasonal change in the distribution and density of seals in the pack ice off Princess Martha Coast, Antarctica

During the period 9 December 1991–4 February 1992 shipboard and aerial surveys of seals in the pack ice off the Princess Martha Coast were made. All aerial surveys were flown from the MV SA Agulhas

The timing of pupping by pack-ice seals in East Antarctica

Observations of the presence or absence of pups with adults during numerous voyages of the Australian National Antarctic Research Expeditions to East Antarctica during spring and early summer months are analysed and presented to provide circumstantial evidence that the maximum durations of lactation reported in the literature for the three species may be over-estimates.


We examine the extent to which the assumptions underlying line transect sampling are satisfied in shipboard surveys of crabeater seals (Lobodon carcinophaga) hauled out on the Antarctic pack-ice.

A top–down, multidisciplinary study of the structure and function of the pack-ice ecosystem in the eastern Ross Sea, Antarctica

We used a top–down, multidisciplinary approach to examine the physical and biological environment of the pack ice of the eastern Ross Sea (approximately 125–170°W) during the austral summer of

Diving behaviour of two Ross seals off east Antarctica

The Ross seal is the least frequently sighted and least known of the Antarctic pinnipeds and its dive patterns suggest that their prey species, thought to comprise mostly fish and squid, were relatively unavailable at depths <100 m.

Estimation of detection probability in aerial surveys of antarctic pack-ice seals

We use line transect detection functions together with generalized linear and additive models to estimate detection probability when detection on the line (“g(0)”) may not be certain. The methods

Continental Estimates and Population Trends of Antarctic Ice Seals

Seal census data accrued during 1968–1983 were incorporated into a standard data format and revised density estimates were calculated. A key element in this reanalysis was time correction of the

Antarctic ecosystems: ecological change and conservation

Long- and Medium-Term Changes in Antarctic Environments.- Significance of Evidence for Changes in the Antarctic Marine Environment Over the Last 5 Million Years.- Temperature and Evolution: Southern