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



(Fig. 2). Although spatial distribution varied greatly 

 in different regions and seasons, vertical distribu- 

 tion showed the same general pattern throughout 

 the entire period of study. During the day, squid oc- 

 curred near bottom at depths ranging from 150 m to 

 800 m, with the greatest densities usually between 

 350 and 450 m. At night, B. magister was generally 

 dispersed throughout the water column. Females 

 always predominated over males, the sex ratio 

 (males/females) varying from 0.6 to 0.8. 



Olyutorsky Bay During June, July, and August, B. 

 magister occurred in small numbers along the slope 

 of Olyutorsky Bay and Shirshov Ridge with average 

 catches <100 kg-tv -1 at depths from 250 to 450 m. 

 Local aggregations of mature squids (from 160 to 270 

 kgh" 1 ) were found in the western part of Olyutorsky 

 Bay and south of Cape Olyutorsky. Dense concen- 

 trations appeared in the eastern part of the Bay and 

 Shirshov Ridge in September, reaching the highest 

 values (1,100-1,400 kgh -1 ) in the first ten days of 



October. Later, smaller numbers of squid were ob- 

 served and by the second half of November had de- 

 creased to 100 kgh -1 or less. 



Navarin-Olyutorsky region In June, density of B. 

 magister shoals along the Navarin-Olyutorsky slope 

 was low; average catches were around 50 kgh -1 . A 

 few large catches (up to 400 kgh" 1 ) were taken in 

 the eastern part of the region between 176°E and 

 177°E. From July to September, numbers of squids 

 increased steadily and catches averaged 700-800 

 kgh 1 by the end of September. The most dense ag- 

 gregations (1,000 to 1,500 kgh -1 ) were captured at 

 depths of 350-450 m between 172°E and 174°E in 

 September and October. By the second half of No- 

 vember, catches of B. magister decreased rapidly to 

 90-100 kgh - 1 . 



Navarin-St. Matthew region From June to August, 

 catches of B. magister were very low (<50 kgh -1 ). 

 Catches increased steadily during September and 



