Distribution, stock structure, and growth of the squid Berryteuthis magister (Berry, 1913) (Cephalopoda, Gonatidae) during summer and fall in the western Bering Sea

• Main Authors: Arkhipkin, A. I., Bizikov, V. A., Nesis, K. N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: US Gov.Print.Off. 1996
• Subjects: Bering Sea; Navarin
• Online Access: https://oceanrep.geomar.de/id/eprint/38651/; https://oceanrep.geomar.de/id/eprint/38651/1/2902.pdf

Distribution, abundance, and length-frequency composition of schoolmaster gonate squid, Berryteuthis magister, were studied during seven trawl surveys in the western Bering Sea between June and November 1993. Statolith age analysis was undertaken for 1,381 B. magister to estimate age, stock structure, and both growth and maturation rates. Three kinds of growth increments were revealed in B. magister statoliths. Daily periodicity of the second-order increments was confirmed by two independent, indirect methods. According to our data, B. magister live >1 yr; the oldest specimen was about 16 months old. Berryteuthis magister is a slow-growing and slow-maturing squid, and males exhibit slower growth and earlier maturation than do females. Growth in length was best described by a logistic curve, with a larger asymptotic parameter for females. In summer, concentrations of B. magister were low within the whole region, whereas in September-October squids aggregated into dense shoals over the continental slope of the Navarin-Olyutorsky region and Olyutorsky Bay. Stock structure of B. magister was complicated: each month, from 5 to 12 (usually 7-8) monthly classes of squid were encountered in the western Bering Sea. Three seasonal groups of B. magister occurred in the region: winter-, summer- and fall-hatched squids utilizing resources of the continental slope in different ways. A possible life cycle for the B. magister fall-hatched group includes a longevity of ca. 2 yr: 6 mo of embryonic development and 18 mo of postembryonic growth.