Reproductive biology of the Patagonian bobtail squid, Semirossia patagonica (Sepiolidae : Rossiinae) in the south-west Atlantic

Abstract

A total of 104 Semirossia patagonica were collected all over the Patagonian shed bet ween the depths of 47 and 295 m. Mature female size varied from 10 to 35 mm ML, mature male size was 16-32 mm. Potential fecundity ranged bet ween 5 27-766 eggs in pre-spawning females, ripe egg size was 3.4-5.0 mm. The oviduct capacity probably was no more than 3 eggs. The maximum number of spermatophores in males was 229. Males transfer 2-19 spermatophores to females during copulation. The ovulation pattern is asynchronous, individual spawning is continuous. Reproduction occurs all year round. Semirossia patagonica is a south-west Atlantic ecological sibling of north-east Atlantic bobtail squids Sepiola spp. and Sepietta spp.