Multiple spawning and spawning batch sizein Sepietta oweniana (Cephalopoda: Sepiolidae)

In order to gather information on the reproductive strategy of the sepiolid squid Sepietta oweniana, direct observations of egg-laying in the aquarium by three wild collected mated females were combined with the examination of the ovaries of 59 specimens. The record of multiple spawning events in two aquarium-kept females (two and eight events, respectively) and the co-existence in the ovaries of oocytes at various stages of maturation, including mature oocytes, showed that S. oweniana is a multiple-spawner. An estimate of the spawning batch size, i.e. the mean number of mature oocytes released at each spawning act, was 54.4 eggs; the overall fecundity was estimated to be on the order of 103 eggs. The multiple spawning reproductive strategy of this sepiolid squid, which continues to grow during its long reproductive phase, was found to differ largely from that of some teuthid squids