Mother dies soon after the young have hatched / Giant Pacific octopus

The giant Pacific octopus (Enteroctopus dofleini), also known as the North Pacific giant octopus, is a large marine cephalopod belonging to the genus Enteroctopus and Enteroctopodidae family. Its spatial distribution encompasses much of the coastal North Pacific, from the Mexican state of Baja California, north along the United States' West Coast (California, Oregon, Washington and Alaska, including the Aleutian Islands), and British Columbia, Canada; across the northern Pacific to the Russian Far East (Kamchatka, Sea of Okhotsk), south to the East China Sea, the Yellow Sea, the Sea of Japan, Japan's Pacific east coast, and around the Korean Peninsula. It can be found from the intertidal zone down to 2,000 m (6,600 ft), and is best-adapted to colder, oxygen- and nutrient-rich waters. It is the largest octopus species on earth and can often be found in aquariums and research facilities in addition to the ocean. E. dofleini play an important role in maintaining the health and biodiversity of deep sea ecosystems, cognitive research, and the fishing industry.
Both male and female giant Pacific octopuses are semelparous, meaning they only go through one breeding cycle in their life.
Unlike most other octopus species, whose lifespans normally span only one year, the giant Pacific octopus has a lifespan of three to five years. They reach sexual maturity at one to two years of age. Gonadal maturation has been linked to the optic gland of octopuses which has been compared functionally to the vertebrate pituitary gland. These optic glands are the only endocrine glands identified in octopuses, and their secretions have been found to contribute to behaviors linked with reproduction and senescence. When removed, females no longer brood their eggs, resume feeding, increase in weight, and experience longer lifespans compared to sexually mature, brooding females who still retain their optic glands.
To help compensate for its relatively short lifespan, the octopus is extremely prolific. It can lay between 120,000 and 400,000 eggs which are coated in chorion, and attached to a hard surface by the female. The spawn is intensively cared for exclusively by the female, who continuously blows water over it and grooms it to remove algae and other growths. While she fulfills her duty of parental care the female stays close to her spawn, never leaving to feed, leading to her death soon after the young have hatched. The female's death is the result of starvation, as she subsists on her own body fats during this period of approximately 6 months. Hatchlings are about the size of a grain of rice, and very few survive to adulthood. Their growth rate is quite rapid: starting from 0.03 g (0.0011 oz) and growing to 20-40 kg (44-88 lb) at adulthood, which is an increase of around 0.9% per day. The giant Pacific octopus' growth over the course of a year has two sections: a faster section, from July to December, and a slower section, from January to June. Because they are cool-blooded, they are able to use most of their consumed energy for body mass, respiration, physical activity, and reproduction. During reproduction, the male octopus deposits a spermatophore (or sperm packet) more than 1 m (3.3 ft) long using his hectocotylus (specialized arm) in the female's mantle. The hectocotylus is found on the third arm of male octopuses and occupies the last four inches of the arm. This part of the male arm anatomy contains no suckers. Large spermatophores are characteristic of octopuses in this genus. The female stores the spermatophore in her spermatheca until she is ready to fertilize her eggs. One female at the Seattle Aquarium was observed to retain a spermatophore for seven months before laying fertilized eggs.