Population dynamics of southern elephant seals: a synthesis of three decades of demographic research at Marion Island

  • PA Pistorius
  • PJN de Bruyn
  • MN Bester

Abstract

Southern elephant seal Mirounga leonina numbers declined precipitously throughout most of their circumpolar distribution since the 1950s. A long-term  intensive demographic programme was initiated in 1983 on the relatively small population of southern elephant seals at sub-Antarctic Marion Island in an attempt to identify causative mechanisms associated with this decline. Weaned pups have been tagged annually since 1983, and this has produced a large number of individuals of known identity. A regular resighting programme yielded a mark-recapture dataset that has been subjected to numerous survivalbased models. This ongoing programme produced a substantial body of scientific literature on  population growth patterns, vital rates (survival and fecundity) and population regulation in southern elephant seals, which are reviewed in this synthesis. We  briefly describe the analytical framework common to much of the  demographic research, highlight important conclusions concerning population regulation of elephant seals at Marion Island, and discuss priorities for future research.

Keywords: environmental change, fecundity, growth, mark-recapture, Mirounga leonina, population regulation, survival

African Journal of Marine Science 2011, 33(3): 523–534

Author Biographies

PA Pistorius
Department of Zoology, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031, South Africa
PJN de Bruyn
Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
MN Bester
Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X