How many octopuses survive adulthood?

None. All Octopuses eventually die in adulthood Another answer If the question was "how many octopuses survive until adulthood," there's a different answer. Under normal circumstances, any species produces just enough young to sustain the species, so each adult female octopus (most of which produce only one brood in their lifetimes) must produce two young that survive until adulthood. Out of a typical clutch of about 200,000 eggs, about 199,998 will die before reaching adulthood.