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

Published online by Cambridge University Press:  04 January 2008

Colin J. Southwell ,
Charles G.M. Paxton ,
David L. Borchers ,
Peter L. Boveng ,
Erling S. Nordøy ,
Arnoldus Schytte Blix  and
William K. De La Mare
Colin J. Southwell*
Affiliation:
Department of the Environment and Water Resources, Australian Antarctic Division, Channel Highway, Kingston, TAS 7050, Australia
Charles G.M. Paxton
Affiliation:
School of Mathematics and Statistics, University of St.Andrews, North Haugh, St Andrews KY16 9SS, UK
David L. Borchers
Affiliation:
School of Mathematics and Statistics, University of St.Andrews, North Haugh, St Andrews KY16 9SS, UK
Peter L. Boveng
Affiliation:
National Marine Mammal Laboratory, 7600 Sand Point Way NE Seattle, WA 98115, USA
Erling S. Nordøy
Affiliation:
Department of Arctic Biology, University of Tromsø, N-9037 Tromsø, Norway
Arnoldus Schytte Blix
Affiliation:
Department of Arctic Biology, University of Tromsø, N-9037 Tromsø, Norway
William K. De La Mare
Affiliation:
CSIRO Marine and Atmospheric Research, Cleveland Laboratories, PO Box 120, Cleveland, QLD 4163, Australia
*
*colin.southwell@aad.gov.au
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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 in 1999/2000 to estimate the status of the Ross seal population in the pack ice off East Antarctica between 64–150°E. Shipboard and aerial sighting surveys were carried out along 9476 km of transect to estimate the density of Ross seals hauled out on the ice, and satellite dive recorders deployed on a sample of Ross seals to estimate the proportion of time spent on the ice. The survey design and analysis addressed the many sources of uncertainty in estimating the abundance of this species in an effort to provide a range of best and plausible estimates. Best estimates of abundance in the survey region ranged from 41 300–55 900 seals. Limits on plausible estimates ranged from 20 500 (lower 2.5 percentile) to 226 600 (upper 97.5 percentile).

Keywords

abundancemodel-based inferencepopulation status
Type
Life Sciences
Information
Antarctic Science , Volume 20 , Issue 2 , April 2008 , pp. 123 - 133
Copyright
Copyright © Antarctic Science Ltd 2008

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References

Ackley, S.F., Bengtson, J.L., Boveng, P., Castellini, M., Daly, K., Jacobs, S., Kooyman, G.L., Laake, J., Quetin, L., Ross, R., Siniff, D.B., Stewart, B.S., Stirling, I., Torres, J. & Yochem, P.K. 2003. A top-down, multidisciplinary study of the structure and function of the pack ice ecosystem in the eastern Ross Sea, Antarctica. Polar Record, 39, 219–230.CrossRefGoogle Scholar
Akçakaya, H.R., Ferson, S., Burgmann, M.A., Keith, D.A., Mace, G.M. & Todd, C.R. 2000. Making consistent IUCN classifications under uncertainty. Conservation Biology, 14, 1001–1013.CrossRefGoogle Scholar
Anonymous. 1994. Antarctic pack ice seal program. Draft Implementation Plan. http://nmml.afsc.noaa.gov/apis/international.htm.Google Scholar
Bengtson, J.L. & Cameron, M.F. 2004. Seasonal haulout patterns of crabeater seals (Lobodon carcinophaga). Polar Biology, 27, 344–349.CrossRefGoogle Scholar
Bester, M.N., Erickson, A.W. & Ferguson, J.W.H. 1995. Seasonal change in the distribution and density of seals in the pack ice off Princess Martha Coast, Antarctica. Antarctic Science, 7, 357–364.CrossRefGoogle Scholar
Blix, A.S. & Nordøy, E.S. 1998. Ross seal diving behaviour and distribution: a reassessment? Proceedings VII SCAR International Biology Symposium. New Zealand Natural Science, 23, Supplement 14.Google Scholar
Borchers, D.L., Laake, J.L., Southwell, C. & Paxton, C.G.M. 2006. Accommodating unmodelled heterogeneity in double-observer distance sampling surveys. Biometrics, 62, 372–378.CrossRefGoogle Scholar
Buckland, S.T., Anderson, D.R., Burnham, K.P., Laake, J.L., Borchers, D.L. & Thomas, L. 2001. Introduction to Distance sampling: estimating abundance of biological populations. Oxford: Oxford University Press, 448 pp.CrossRefGoogle Scholar
Craven, P. & Wahba, G. 1979. Smoothing noisy data with spline functions. Numerische Mathematik, 31, 377–403.CrossRefGoogle Scholar
Eklund, C.R. & Atwood, E.L. 1962. A population study of Antarctic seals. Journal of Mammalogy, 43, 229–238.CrossRefGoogle Scholar
Erickson, A.W. & Hanson, M.B. 1990. Continental estimates and population trends of Antarctic seals. In Kerry, K.R. & Hempel, G., eds. Antarctic ecosystems: ecological change and conservation. Berlin: Springer, 253–264.CrossRefGoogle Scholar
Gilbert, J.R. & Erickson, A.W. 1977. Distribution and abundance of seals in the pack ice of the Pacific sector of the Southern Ocean. In Llano, L., ed. Adaptations within Antarctic ecosystems. Washington, DC: Smithsonian Institute, 703–740.Google Scholar
Hastie, T.J. & Tibshirani, R.J. 1990. Generalized additive models. London: Chapman and Hall, 352 pp.Google Scholar
Hedley, S.L., Buckland, S.T. & Borchers, D.L. 1999. Spatial modelling from line transect data. Journal of Cetacean Research and Management, 1, 255–264.CrossRefGoogle Scholar
Horvitz, D.G. & Thompson, D.J. 1952. A generalization of sampling without replacement from a finite universe. Journal of the American Statistical Association, 47, 663–685.CrossRefGoogle Scholar
IUCN. 2006. IUCN Red list of threatened species. www.iucnredlist.org.Google Scholar
Martin, T.G., Wintle, B.A., Rhodes, J.R., Kuhnert, P.M., Field, S.A., Low-Choy, S.J., Tyre, A.J. & Possingham, H.P. 2005. Zero tolerance ecology: improving ecological inference by modelling the source of zero observations. Ecology Letters, 8, 1235–1246.CrossRefGoogle ScholarPubMed
Maxwell, G. 1967. Seals of the world. London: Constable, 168 pp.Google Scholar
Mullahy, J. 1986. Specification and testing of some modified count data models. Journal of Econometrics, 33, 341–365.CrossRefGoogle Scholar
Nordøy, E.S., Folkow, L. & Blix, A.S. 1995. Distribution and diving behaviour of crabeater seals (Lobodon carcinophagus) off Queen Maud Land. Polar Biology, 15, 261–268.CrossRefGoogle Scholar
Nordøy, E.S. & Blix, A.S. 2001. The previously pagophilic Ross seal is now rather pelagic. Proceedings VIII SCAR International Biology Symposium, Abstract, Vrije University, Amsterdam, The Netherlands.Google Scholar
Nordøy, E.S. & Blix, A.S. 2005. Haulout behaviour of Ross seals in King Haakon VII Sea. Proceedings IX SCAR International Biology Symposium, Curitiba, Brazil.Google Scholar
R Development Core Team, 2005. R: a language and environment for statistical computing. Vienna: R Foundation for Statistical Computing. http://www.R-project.orgGoogle Scholar
Sato, K., Tsuchiya, Y., Kudoh, S. & Naito, Y. 2003. Meteorological factors affecting the number of Weddell seals hauling-out on the ice during the molting season at Syowa Station, East Antarctica. Polar Bioscience, 16, 98–103.Google Scholar
Scheffer, V.B. 1958. Seals, sea lions and walruses. a review of the Pinnipedia. Palo Alto, CA: Stanford University Press, 190 pp.Google Scholar
Scott, P. 1965. Section XIII. Preliminary List of Rare Mammals and Birds. In Scott, P., ed. The Launching of a New Ark. First report of the President and Trustees of the World Wildlife Fund. An International Foundation for Saving the World's Wildlife and Wild Places, 1961–1964. London: Collins.Google Scholar
Skinner, J.D. & Westlin-van Aarde, L.M. 1989. Aspects of reproduction in female Ross seals (Ommatophoca rossii). Journal of Reproduction and Fertility, 87, 67–72.CrossRefGoogle ScholarPubMed
Smith, W.H.F. & Sandwell, D.T. 1997. Global sea floor topography from satellite altimetry and ship depth soundings. Science, 277, 1956–1962.CrossRefGoogle Scholar
Southwell, C. 2003. Haulout behaviour of two Ross seals off eastern Antarctica. Antarctic Science, 15, 257–258.CrossRefGoogle Scholar
Southwell, C. 2005a. Optimising the timing of visual surveys of crabeater seal abundance: haulout behaviour as a consideration. Wildlife Research, 32, 333–338.CrossRefGoogle Scholar
Southwell, C.J. 2005b. Diving behaviour of two Ross seals in East Antarctica. Wildlife Research, 32, 63–65.CrossRefGoogle Scholar
Southwell, C., de la Mare, B., Borchers, D.L. & Burt, L. 2004. Shipboard line transect surveys of crabeater seal abundance in the pack ice off East Antarctica: evaluation of assumptions. Marine Mammal Science, 20, 602–620.CrossRefGoogle Scholar
Southwell, C., Borchers, D., Paxton, C.G.M., Burt, L. & de la Mare, W.K. 2007a. Estimation of detection probability in aerial surveys of Antarctic pack ice seals. Journal of Agricultural, Biological and Environmental Statistics, 12, 41–54.CrossRefGoogle Scholar
Southwell, C., de la Mare, W., Underwood, M., Quartararo, F. & Cope, K. 2002. An automated system to log and process distance sight-resight aerial survey data. Wildlife Society Bulletin, 30, 394–404.Google Scholar
Southwell, C., Kerry, K., Ensor, P., Woehler, E. & Rogers, T. 2003. The timing of pupping by pack ice seals in East Antarctica. Polar Biology, 26, 648–652.CrossRefGoogle Scholar
Southwell, C., Paxton, C.G.M., Borchers, D.L., Boveng, P. & de la Mare, W.K. 2007b. Taking account of dependent species in management of the Southern Ocean krill fishery: estimating crabeater seal abundance off East Antarctica. Journal of Applied Ecology, 10.1111/j.1365-2664.2007.01399.x.Google Scholar
Williams, B.K. 2001. Uncertainty, learning, and the optimal management of wildlife. Environmental and Ecological Statistics, 8, 269–288.CrossRefGoogle Scholar
Williams, B.K., Nichols, J.D. & Conroy, M.J. 2002. Analysis and management of animal populations. modeling, estimation, and decision making. San Diego: Academic Press, 1040 pp.Google Scholar
Wood, S.N. 2006. Generalized additive models. an introduction with R. Boca Raton, FL: Chapman and Hall, 416 pp.CrossRefGoogle Scholar
Zorn, C.J.W. 1996. Evaluating zero-inflated and hurdle poisson specifications. Midwest Political Science Association, April 1996, 1–16.Google Scholar