Quantifying fin shape in Brachioteuthis beanii (Cephalopoda: Brachioteuthidae) collected at The Gully Marine Protected Area, off Nova Scotia, Canada

Abstract

Oegopsid squid fin shape changes with ontogeny and identifying the timing of these changes may distinguish between phases and stages of cephalopod life cycles. Fin shape of Brachioteuthis beanii was analyzed in 67 specimens (41–105 mm ML) divided into 5 groups based on size and sex. Male and female adult fins are the same shape, but the adult shape is different from juvenile and subadult shape. The Angle of Maximum Height and Width were similar across B. beanii in the size groups treated (AMxH =16 ± 2°and AMxW= 70 ± 3°). In brachioteuthids, the difference between a saggitate fin and a rhomboidal fin may be a function life cycle phase.