C-12 



(Laws, 1977)- Distribution of all species is circumpolar, 

 with larger species and larger Individuals within species 

 penetrating further south (BIOMASS, 1977). 



Benthos 



Benthic communities occur along the Antarctic conti- 

 nental shelf and around islands. Energy sources for the 

 benthic community come from seaweed production and from 

 sinking of krill and other detritus from the water column. 



There is no commercial harvesting of Antarctic benthos 

 at predeur. . Some seaweeds occur in harvestable quantities, 

 particularly the brown algae Macrocystis pyrifera and 

 DuTvillea antarctica and red algae such as the Gelidiales 

 or Gigartinales . 



In the subantarctic , rock lobsters (janus sp.) are 

 harvested. Several antarctic invertebrates (the scallop 

 Adamussium colbecki , the clam Laternula elliptica , the 

 gastropod Neobuccinum eatoni , and sea urchins Sterechinus 

 sp.) are similar to species exploited elsewhere. However, 

 small stocks combined with logistic difficulties indicate 

 that commercial harvesting would not be practical. 



Exchanges with Other Ecosystems 



Carbon and nutrients are exported from the Antarctic 

 ecosystem through migration of whales, some fish, and some 

 birds. Nutrients are also lost through a presently small 

 krill harvest, fish harvesting and whaling. A much larger 

 krill harvest is anticipated in future years. In addition, 

 other fish species, squid and possibly some seals constitute 

 potential harvestable resources. 



The Antarctic marine ecosystem is well integrated. 

 Component species and relationships between them have 

 evolved together. There do not appear to be any empty 

 niches. All the available resources are used within the 

 system. It is very difficult for an outside species to in- 

 vade a healthy ecosystem successfully. (Only systems under 

 stress, such as the polluted Great Lakes, are susceptible to 

 major faunal changes). Thus, importing a new species such 

 as salmon to migrate across the Convergence, eat krill, and 

 then return north to be harvested, is not expected to work 

 on ecological grounds. In the case of salmon, there are 

 also biological and physical oceanographic problems with 

 establishing a population north of the Convergence. 



