Arkhipkin et al.: Distribution, stock structure, and growth of Berryteuthis magister 



June - July 



September - 



October 



o 



< 100 



O 



1(1(1- 500 



o 



500- 1000 



O 



> 1000 



Figure 2 



Distribution of Berryteuthis magister in the western Bering Sea, June-July 

 and September-October 1993. Circles indicate trawl catches of squids (kg-h -1 1. 



June (75%) to July-August (90%), then decreased 

 abruptly in October (37%). Spent females appeared in 

 July ( 1% ■). In August— October, their numbers were low, 

 except for a few catches along the Shirshov Ridge. Spent 

 females were most abundant in November ( 11-12%). 

 Juveniles were seldom caught from July to Octo- 

 ber. Their size range was wide (20-120 mm). Juve- 

 nile length composition was bimodal in summer and 

 without well-expressed modes in fall. 



Navarin-Olyutorsky region In the Navarin- 

 Olyutorsky region (Fig. 4), proportions of immature 

 and maturing males gradually decreased from June 

 to August. During September and October, both 

 groups almost vanished from catches (<2% each) and 

 appeared again in November. Length composition of 

 immature males was roughly unimodal (160-170 

 mm). Mantle length of the largest immature males 

 never exceeded 200 mm. Length composition of ma- 

 turing males was unimodal and wide ( 150-240 mm ), 

 with modes shifting slightly from June ( 170-180 mm ) 

 to October ( 190-200 mm). 



Among males, mature animals always predomi- 

 nated in catches, with the greatest number in Sep- 

 tember and October (95%). The size range of mature 

 males was wide ( 170-290 mm) and did not vary con- 

 siderably from June to November. The size composi- 

 tion was distinctly unimodal (modal length was 210 

 mm during the entire period of study). The number 

 of spent males was extremely low from June to Octo- 

 ber and increased slightly in November (3%). Their 

 sizes always coincided with modal lengths of mature 

 males. 



Numbers of immature females decreased succes- 

 sively from June to September. In October, their pro- 

 portion remained low, then expanded slightly in No- 

 vember. The size range of immature females was al- 

 ways wide, with largest individuals of about 280 mm 

 ML. Length composition had two modes in June 

 (180-190 mm and 220-230 mm), and three in July 

 ( 130 mm; 190-200 mm; and 240 mm). In August, only 

 one very broad mode was traced among this group 

 ( 190-240 cm). From September to November, length 

 composition of immature females had no clear modes. 



