-no- 



marine environments through harassment, habitat destruction, 

 and dumping of polluting effluents. Seabird nesting areas 

 and seal rookeries could easily be affected by harvest- 

 related activities as well as by harassment by tourists. 



3 . Summary 



There is evidence that whaling caused shifts in the 

 Southern Ocean trophodynamic structure by removing a major 

 biological component, baleen whales, from the upper levels 

 of the food web. An intensive krill harvest could again 

 cause major, and even more dramatic, shifts in the trophodynamics 

 of the Antarctic marine ecosystem by exploiting a resource 

 at the foundation of the entire food web. Because the 

 implications of exploiting a resource on which so many other 

 species are directly or indirectly dependent are largely 

 unknown, it is clear that extreme caution must be exercised. 



