H-20 



RESEARCH PROGRAMMES 



are in tlie north, it is well known that the stocks of large whales have been commercially 

 overfished in the Southern Ocean since 1904, and with the exception of the Minke Whale are 

 still very low compared with their former abundance. 



There is a need for proper conservation and management and a growing awareness of the 

 complex interactions between seals and whales involving possible competition for food with 

 each other and with birds, fishes and squids. Two international conventions are concerned with 

 the marine mammals: the International Whaling Convention, dating from 1931, and the 

 Convention for the Conservation of Antarctic Seals, signed in 1972 but not yet in force. 

 The SCAR Group of Specialists on Seals and the Subcommittee on Bird Biology of the SCAR 

 Working Group on Biology are also active in this field. Adequate conservation and management 

 depends on a continuing input of data and information. 



2.5.2 Ecology and abundance 



1. Seals 



The pack ice region around Antarctica is the habitat of the Antarctic seals. These are the 

 Crabeater Seal Lobodon carcinophagus, the Weddell Seal Leptonychotes weddelli, the Leopard 

 Seal Hydrurga leptonyx. and the Ross Seal Omatophoca rossi. These species have recently 

 drawn considerable worldwide attention since they are a resource as yet unexploited by man. 

 Other seal species which inhabit the Southern Ocean are the Southern Elephant SQzXMirounga 

 leonina and the Fur Seals Arctocephalus gazella and A. trapicalis. ihese species were 

 overexploited by the 18th and 19th century sealers and the stocks are still recovering. 



Table 1 . Crude estimates of antarctic seal populations, 

 biomass and food consumption 



Thousands of metric tons. 



Assumed proportions in absence of pelagic data. 

 ^Totals rounded. 



Scientific studies on Antarctic seals began in tlie early 1900's. Most of the work since has 

 been carried out from icebreaker support vessels or in close association with the Antarctic shore 

 stations. In general, the Crabeater, Leopard and Ross seals are distributed in the pack ice 

 regions surrounding the Antarctic continent. Erickson and Hofman (1974) have provided maps 

 which summarize information on distribution and abundance of these species based on census 

 information from the years 1968 and 1974. Estimates of the abundance of various species in 

 these regions are presented in Table 1. For the pack ice species the estimates have been 

 corrected for variation which might occur in surface counts due to the seals' 24-hour activity 

 pattern, but they are, nevertheless, underestimates because an unknown proportion is in the 

 water even at peak haul out times. 



