Octopus vulgaris life cycle: growth, reproduction and senescence in captivity

Cephalopod International Advisory Council Conference, Cephalopods in the Anthropocene: Multiple Challenges in a Changing Ocean, April 2-8, 2022, Sesimbra, Portugal

The common octopus Octopus vulgaris is the best-known octopod, but there are aspects of their life cycle still poorly known. Here we report the complete life cycle of seven O. vulgaris specimens reared in captivity from wild eggs. The shift from a planktonic to a fully benthic life took around 30-45 days and three different stages were identified based on behavioural and tissular changes: pre-settlement (~d45-60, 20-25 suckers), settlement (~d60-75, 25-35 suckers) and post-settlement (~d75-90, >35 suckers). Octopus vulgaris growth curve was effectively modelled with an initial exponential phase (d0~240), followed by a slower power growth phase (d240~500). The inflexion point matched with the development of enlarged suckers in males and the onset of mating behaviours (~220-420g). Up to 52 copulations were observed in 7 months. Spermatophore pumping speed along the hectocotylus was around 0.36 m/s. Spawning started from d512 to d546 at sizes ranging between 6.3-7.7 kg. Egg laying took between 16 and 21 days, while incubation took 49 and 63 days at 18ºC and 14ºC, respectively. Hatching lasted for up to 25 days. Natural deaths were recorded for five specimens. Oviducal gland dissection revealed live sperm >4 months after the last recorded copulation. Skin decolouration and putrefaction of arm tips followed by autophagy of rotten tissue was a common sign of senescence, except for the male´s hectocotylus that remained fully functional. Males grew bigger (9.6-14.6 kg) and lived longer (d796-829) than females (7.2-10.1 kg, d560-638), the largest and oldest specimens ever recorded in captivity

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