from long-line fishing for toothfish
note: the now-protected fur seal population is making a strong
comeback after severe overexploitation in the 18th and 19th centuries

Environment - international agreements:

the Southern Ocean is subject to all international agreements
regarding the world's oceans; in addition, it is subject to these
agreements specific to the Antarctic region: International Whaling
Commission (prohibits commercial whaling south of 40 degrees south
[south of 60 degrees south between 50 degrees and 130 degrees
west]); Convention on the Conservation of Antarctic Seals (limits
sealing); Convention on the Conservation of Antarctic Marine Living
Resources (regulates fishing)
note: many nations (including the US) prohibit mineral resource
exploration and exploitation south of the fluctuating Polar Front
(Antarctic Convergence), which is in the middle of the Antarctic
Circumpolar Current and serves as the dividing line between the cold
polar surface waters to the south and the warmer waters to the north

Geography - note:

the major chokepoint is the Drake Passage between South America and
Antarctica; the Polar Front (Antarctic Convergence) is the best
natural definition of the northern extent of the Southern Ocean; it
is a distinct region at the middle of the Antarctic Circumpolar
Current that separates the cold polar surface waters to the south
from the warmer waters to the north; the Front and the Current
extend entirely around Antarctica, reaching south of 60 degrees
south near New Zealand and near 48 degrees south in the far South
Atlantic coinciding with the path of the maximum westerly winds

Economy
Southern Ocean

Economy - overview:

Fisheries in 2005-06 landed 128,081 metric tons, of which 83%
(106,591 tons) was krill (Euphausia superba) and 9.7% (12,364 tons)
Patagonian toothfish (Dissostichus eleginoides), compared to 147,506
tons in 2004-05 of which 86% (127,035 tons) was krill and 8% (11,821
tons) Patagonian toothfish (estimated fishing from the area covered
by the Convention of the Conservation of Antarctic Marine Living
Resources (CCAMLR), which extends slightly beyond the Southern Ocean
area). International agreements were adopted in late 1999 to reduce
illegal, unreported, and unregulated fishing, which in the 2000-01
season landed, by one estimate, 8,376 metric tons of Patagonian and
Antarctic toothfish. In the 2006-07 Antarctic summer, 35,552
tourists visited