Schmidt Robot Films Mother Squid Carrying Up to 3,000 Eggs off Chile

Q: Why would a deep-sea squid willingly starve to death while carrying thousands of eggs through predator-infested waters?

It does so because, in evolutionary terms, sacrificing the mother can be the best way to maximize the survival of her genes. For the black-eyed squid, *Gonatus onyx*, brooding appears to give the eggs a much better chance of surviving in the deep sea. The mother keeps a mass of up to 3,000 eggs suspended from hooks on her arms for six to nine months, instead of leaving them on the seafloor. While carrying them, she pumps water over the cluster to supply oxygen and help the hatchlings emerge. In the deep ocean, where oxygen, currents, predators and seafloor conditions can all threaten eggs, that constant care may sharply improve the odds that at least some young survive. The cost is extreme. Scientists say a brooding female stops feeding after laying the eggs, moves more slowly, and becomes easier prey for predators such as deep-diving marine mammals. By the time the young hatch, she is expected to be near death. But that trade-off fits a life-history pattern seen in many squid and other cephalopods: they invest heavily in a single reproductive effort near the end of life rather than preserving themselves for future breeding. So the squid is not “choosing” death in a human sense. Natural selection has favored a strategy in which one final, high-risk burst of parental care produces more surviving offspring than abandoning the eggs would. The rare new footage matters because it shows that this costly strategy is not theoretical; it is happening in the wild.

2 articles · Updated · BBC Discover Wildlife · Jul 25

Autumn 2024 footage from a Schmidt Ocean Institute robot shows a black-eyed squid brooding a large egg mass in deep water off Chile, a rarely recorded behavior.
Gonatus onyx is unusual because most squid leave eggs on the seafloor; females instead carry the cluster on hooks on their arms and keep it suspended.
Up to 3,000 eggs can be carried for six to nine months, with the mother pumping water over them to supply oxygen and help mature hatchlings break free.
That brooding leaves the squid slow-moving and unfed, making her vulnerable to predators and leaving her close to death by the time the eggs hatch.