Ocean temperatures of 25°C lead to the premature death of octopus mothers, from heat stress, before their eggs have hatched.

The article is confused when it talks about "unborn offspring". Octopus eggs are not "born", any more than birds' chicks are "born" when they hatch. Baby octopuses do not develop inside their mother. However, the mother must circulate water for them constantly until they are ready to swim away.

It is too bad that the experiment did not report on the visual capabilities of octopuses that did hatch at 25°C. That is the only way to tell for certain whether that water high temperature will damage their vision.

It is possible that octopuses can evolve to adopt to warmer conditions, if the change is not terribly fast. Or they can survive farther from the equator.