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U.S. NATIONAL MUSEUM BULLETIN 291 



'" ° 6.0 . '00 



Figure 72. 



-Vertical distribution by 2S0-meter increments of the total sample population of 

 Crystalloteuthis glacialis Chun, 1906. Antarctic. 



just below the sharp decrease in catch. The average number of speci- 

 mens per tow for the total tows ranges from a minimum of 0.14 at 

 the shallowest and deepest depth intervals to maximums of 1.58 and 

 1.78 in the 500-1000 m increments. 



Although considerable overlap exists in the vertical ranges of G. 

 glacialis and B. ahyssicola, the zones of maximum abundance are dis- 

 tinct, the former species between 500-1000 m and the latter between 

 1000-2250 m. B. abyssicola, however, is associated with G. glacialis 

 more than with any other pelagic Antarctic cephalopod. The two spe- 

 cies frequently are caught in the same tow, but these generally are tows 

 that have fished deeper than 1000-1500 m into the zone of abundance of 

 B. dbyssicola. 



Perhaps the most distinctive feature of the distribution of G. glaci- 

 alis is that it is strictly limited in its northward extent by the location 

 of the Antarctic Convergence. This is truly an Antarctic squid that 

 is found extremely rarely north of the convergence, and then only as a 

 straggler. It is found in the convergence zone but especially south of 

 the convergence in the Circumpolar Water Mass. The details of the 

 distribution must await a more thorough analysis, but at least the 

 boundaries are clear. In fact, G. glacialis can be used as an indicator 

 species ; aboard Eltanin the location of the Antarctic Convergence can 



