Around the end of spring and during summer, young octopods hatch in Galician waters. After hatching, an Octopus vulgaris begins its life as a tiny planktonic paralarva, drifting around in the ocean. The duration of this phase depends on the temperature of the sea water. Generally, most octopus species live fast and die young. They grow rapidly and mature. Maturation is driven by hormones from the optic gland. In the prime of their vitality, when they have reached their full size and greatest weight, the mating season begins. Both females and males engage in multiple romances. This is the peak of their life, but the descent begins immediately after—both sexes have now reached the end of their life cycle. Male octopods then develop a phenomenon called senescence, in which hey lack appetite and lose about 17% of their body weight within about 50 days. The skin on their shrinking bodies retracts from the eyes until they seem to protrude; white lesions on their skin appear that won’t heal, and the animals get restless, spending a lot more time active than usual. Their increased activity is undirected, clumsy, and incautious, making them an easy prey for predators. Their mental capacity deteriorates, sometimes making them eat their own arms. Females on the other hand have one more task to fulfill: they, too, stop feeding, but they stay with their eggs to protect, clean, and oyxgenate them. Once the eggs have hatched, females show similar signs to males, as they too have reached the end of their life cycle. At an age of about two years, both die around the same time, making room for a new generation.
Sources: Anderson, Roland, Wood, James, and Byrne, Ruth, “Octopus Senescence: The Beginning of the End”, Journal of applied animal welfare science, vol. 5, issue. 4, (2002): 275-283.
del Carmen Garcia Martinez, Maria et al., “Short comment about the octopus life cycle in the northern Alboran Sea (western Mediterranean Sea)”, J Fish Res, vol. 1, issue. 1, (2017): 11-37.