Warming oceans could harm octopus vision

Australian researchers have warned that heat stress could result in sight loss among octopuses

A large reddish-brown octopus holds its tentacles up. The undersides of its tentacles are white with rows of protruding suckers

Scientists from the University of Adelaide have highlighted the detrimental effect of warming oceans on octopus vision – which could possibly pose a risk for their survival.

Writing in Global Change Biology, researchers explore the effects of heat stress on different proteins important for vision within the eyes of octopuses.

Groups of Octopus berrima embryos were exposed to different water temperatures – a control of 19 degrees, current summer temperature of 22 degrees and the future projected summer temperature of 25 degrees.

They found that a protein responsible for preserving lens transparency and another protein that regenerates visual pigments in the photoreceptors was affected by higher temperatures.

Around 70% of an octopus’ brain is dedicated to vision – compared to roughly 50% of the brain in humans.

The function is crucial for octopuses to be able to detect predators and prey.

"Having impaired vision will affect an octopus’s chances of survival in the wild through increased predator risk as well as lower foraging success,” shared Dr Qiaz Hua, a PhD graduate from the University of Adelaide.

As well as finding a detrimental effect on vision, scientists determined that warmer ocean temperatures would increase embryonic mortality rates among octopuses.