Fishery Bulletin 98(1) 



thus it is difficult to explain the reasons for such a dif- 

 ference in length composition between the two years. 

 It was found that /. argentinus caught by jigging gear 

 were significantly larger and more mature (especially 

 females) than trawl-caught squid fished in the same 

 location and time (Koronkiewicz, 1995). Thus, differ- 

 ences in age and length compositions observed in 1989 

 and 1991 can be explained by interannual changes 

 in population structure of/, argentinus rather than 

 by various selectivity of the two different sampling 

 gears. 



The results of the present study show that in Janu- 

 ary-April, the international squid fishery in the south- 

 west Atlantic catches aggregations of both groups of 

 winter-spawned/, argentinus. Squid of the shelf group 

 are captured by trawlers and jigging vessels over the 

 depth range of 150—200 m mainly in the region of 

 45^9°S. Squid of the slope group are caught by trawl- 

 ers and jigging vessels mainly in the southern part of 

 the Patagonian Shelf within the EEZA(47-51°S) over 

 the depth range of 150-250 m in February-March, 

 and by trawlers over the continental slope (45^7°S) 

 at depths of 600-700 m in April. 



Acknowledgments 



I gratefully acknowledge the generous help of scientific 

 observers of the trawlers Anc/ior, Volzhanin, Petropav- 

 lovskaya krepost and Batiliman for data sampling. I 

 would like to thank L. A. Vavilova and A. B. Mikheev 

 for processing statoliths, Ch. M. Nigmatullin and A. 

 Z. Sundakov for discussions and comments on an ear- 

 lier version of the manuscript. The edtiorial work 

 of Emma Hatfield (NOAA, Woods Hole) and Emma 

 Jones (FIFD, Stanley, Falkland Islands), who helped 

 with the text in English, is most appreciated. 



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