The complete guide to Antarctic wildlife: birds and marine mammals of the Antarctic continent and the Southern Ocean

2008 ◽  
Vol 45 (11) ◽  
pp. 45-6171-45-6171

Mr President, ladies and gentlemen: it is my pleasure, in opening this two-day conference on the terrestrial Antarctic ecosystem, to welcome you as contributors of papers and, as I shall hope, participants in the discussions with which we will conclude each of the four sessions of our meeting. This symposium was first suggested and has, in very large measure, been organized by Dr Martin Holdgate whom we regretfully, but nevertheless most warmly congratulate on his recent translation from the post of Senior Biologist of the British Antarctic Survey to that of Deputy Director of the Nature Conservancy. The furtherance of Antarctic biology in recent years owes much to Dr Holdgate’s energetic and imaginative direction, and I am glad to have this opportunity of acknowledging our indebtedness to him for arranging this discussion. The Antarctic continent, half as large again as Australia, and the surrounding Southern Ocean, in area about one-fifth of the world’s sea surface were, by their very remoteness from the maritime nations of the northern hemisphere, late of exploration. But, while it is little more than 75 years since man first set foot on the Antarctic continent, the more accessible waters of the Southern Ocean have an appreciably longer history of exploration, dating from the pioneering voyages of Captain Cook some 200 years ago. Biological investigations in Antarctica were, therefore, for long concerned almost entirely with observations and studies of animals living in the open ocean or on the sea floor rather than with the terrestrial and freshwater floras and faunas of the continental margin and oceanic islands which, either because of difficulties of access or limitations of time imposed by ships’ programmes, were rarely surveyed in detail.


1978 ◽  
Vol 20 (84) ◽  
pp. 533-542 ◽  
Author(s):  
J.G. Job

AbstractsThe towing of unprotected icebergs from the Antarctic continent (66° S.) to latitude 38° S. has been simulated using an explicit hydrodynamic model and an extended two-dimensional melting model. It was found that nominal towing accelerations in excess of 2 × 10-5m s-2were required to deliver ice over this route in most circumstances, and minimum energy consumptions were obtained at accelerations around 10-4m s-2. Unprotected icebergs could be delivered with about 50% yield to latitude 38° S., but the rate of deterioration in the warm waters indicates that protection would be required for longer journeys. The towing simulation was most sensitive to north-south current components, the total towing distance and the rate of iceberg deterioration. Efforts directed towards locating suitable icebergs in the region 50° S. to 60° S., and towards increasing knowledge of the changing current patterns in the Southern Ocean would be most valuable, as would a knowledge of the mechanisms and rates of deterioration of icebergs in warm seas.


2005 ◽  
Vol 32 (2) ◽  
pp. 334-345
Author(s):  
John Turner

Great advances have been made in recent years in our understanding of the weather of the Antarctic and how the climate of the continent varies on a range of time-scales. The observations from the stations are still the most accurate meteorological measurements that we have, but satellites have been important in providing data for remote parts of the continent and the Southern Ocean. With the large amount of data that is available today weather forecasts are much more accurate than just a few years ago and can provide valuable guidance up to several days ahead over the Southern Ocean and Antarctic coastal region. However, predicting the weather for the interior of the Antarctic is still very difficult. Recent research has shown that the climate of the Antarctic is affected by tropical atmospheric and oceanic climate cycles, such as the El Niño-Southern Oscillation, but the links are complex. The picture of climate change across the Antarctic during the last 50 years is complex, with only the Antarctic Peninsula showing a significant warming. By the end of the twenty-first century near-surface air temperatures across much of the Antarctic continent are expected to increase by several degrees. A small increase in precipitation is also expected.


Polar Record ◽  
2013 ◽  
Vol 50 (1) ◽  
pp. 92-107 ◽  
Author(s):  
David G. Ainley ◽  
Daniel Pauly

ABSTRACTThe history of biotic exploitation for the continental margin (shelf and slope) of the Antarctic Large Marine Ecosystem (LME) is reviewed, with emphasis on the period from 1970 to 2010. In the Antarctic Peninsula portion, marine mammals were decimated by the 1970s and groundfish by the early 1980s. Fishing for Antarctic krill Euphausia superba began upon the demise of groundfish and now is the only fishing that remains in this region. Surveys show that cetacean and most groundfish stocks remain severely depressed, harvest of which is now prohibited by the International Whaling Commission and the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). On the other hand, krill fishing in this region is underway and in recent years has contributed up to 72% of the Southern Ocean catch, depending on fishing conditions and the CCAMLR conservation measures in force. Elsewhere along the Antarctic continental margin, marine mammals were also severely depleted by the 1970s, followed directly by relatively low-level fisheries for krill that continued until the early 1990s. Recently in these areas, where fin-fishing is still allowed, fisheries for Antarctic toothfish Dissostichus mawsoni have been initiated, with one of this fish's main prey, grenadiers Macrourus spp., being taken significantly as by-catch. Continental margin fishing currently accounts for ~25% of the total toothfish catch of the Southern Ocean. Fishing along the Antarctic continental margin, especially the Antarctic Peninsula region, is a clear case of both the tragedy of the commons and ‘fishing down the food web’.


There are fewer species of marine mammals in the Antarctic than in the Arctic, probably because of the wide deep ocean with no geographical barriers to promote speciation. The stocks are substantially larger in the Antarctic and the body sizes of individual species are larger, probably owing to a more abundant food supply. Seasonal changes in the environment in the Southern Ocean are marked and food available to baleen whales is very much greater in summer. Ecological interactions of the consumers, principally in relation to krill Euphausia superba , are discussed and attention drawn to some of the ways in which ecological separation is achieved, both within and between species. Estimates of abundances, biomasses and food requirements are given for the seals and large whales. The original numbers of whales in the Antarctic were far greater than in other oceans, but the stocks have been severely reduced by whaling. This may have increased the availability of krill to other consumers by as much as 150 million tonnes annually. Increased growth rates, earlier maturity and higher pregnancy rates have been demonstrated for baleen whale species, and earlier maturity for the crabeater seal. While it has not been possible to demonstrate increases in the populations of any of these species, the stocks of fur seals and penguins have been monitored and show significant population increases. A key question is whether the original balance of this ecosystem can be regained with appropriate management.


The antarctic climate is unfavourable to the development of a land flora, and the true land fauna is meagre and inconspicuous, consisting of little more than a few insects and fresh water Crustacea; but the water circulation of the southern ocean allows for a rich production of phytoplankton, and we have a very abundant fauna living in or on the sea. Topographical and oceanographical conditions The Antarctic continent (figure 74) is surrounded by a belt of deep, cold ocean, generally very wide, which constitutes a rather effective barrier to shelf-living organisms, but within which the physical conditions tend to be uniform in a circumpolar direction. There are, however, certain submarine ridges which radiate from the continent and which may offer routes or stepping stones for dispersal. Thus the Scotia Arc connects South America with Graham Land and has several island groups. The Kerguelen Gaussberg Ridge (about 70° - 90° E) has fewer islands but no wider gaps of abyssal depths, and south of New Zealand the deep belt is narrower than at most other points.


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