Statolith microstructure of seven species of Antarctic squid captured in Prydz Bay, Antarctica

Abstract

The statolith microstructure was examined from seven species of seven families of Antarctic squid captured in Prydz Bay (n=23). Five of the species (Kondakovia longimana, Psychroteuthis glacialis, Brachioteuthis sp., Mastigoteuthis psychrophila, Galiteuthis glacialis) had very clear statolith growth increments which could be enumerated from the nucleus to the statolith margin. These increments were similar in appearance to daily statolith increments in other temperate and tropical squids. Psychroteuthis glacialis also had two distinct zones which may reflect growth during the pelagic and demersal phases of the life cycle. Total statolith increment counts were not possible on two of the species (Bathyteuthis abyssicola and Alluroteuthis antarcticus). The statolith microstructure of Bathyteuthis abyssicola had some very faint increments near the nucleus but increments were not visible in most of the statolith microstructure, while the statolith microstructure of A. antarcticus was indistinct in the nuclear region (possibly due to the formation of a second primordium during ontogenesis). Future research may reveal that statolith increments are useful tools for Antarctic squid age and growth studies.