Climate change has led to an increase in the abundance of octopuses, but new research shows that projected ocean warming could impair their vision, affecting their chances of survival in the wild. Dr. Qiaz Hua, a recent PhD graduate from the University of Adelaide, found that proteins important for vision were significantly reduced under projected ocean warming conditions. This suggests that octopus vision is likely to be impaired under thermal stress. Octopuses are highly visual animals, with 70 per cent of their brain dedicated to vision, making impaired vision a significant threat to their survival.
The primary functions of vision for octopuses include visual acuity, discrimination of brightness, depth perception, motion detection, polarisation, and crucially, for detecting predator and prey, as well as for communication. Impaired vision will increase predator risk and lower foraging success for octopuses, impacting their overall survivability. To make this finding, the research team exposed Octopus berrima embryos to different temperature treatments, including current and projected future ocean temperatures based on the Intergovernmental Panel on Climate Change’s projected increase of about 3°C of warming by 2100.
In addition to impaired vision, increased ocean water temperatures were found to have a negative effect on octopus broods. High mortality rates were observed under future warming conditions, with some octopus broods experiencing no hatching of eggs and mothers dying in early development stages. Dr. Hua’s research shows that global warming could have a simultaneous impact on multiple generations of octopuses, with low survival rates of embryos caused by both direct and indirect effects of thermal stress on the mothers. This suggests that even highly adaptable species like octopuses may struggle to survive future ocean changes.
Other effects of higher temperatures observed in octopuses include a higher metabolic rate, reduced size at maturity, and shifts in the distribution of some species. Future research is needed to examine a combination of environmental stressors including ocean acidification, warming, and deoxygenation to better understand the impacts on octopus populations. A transgenerational experiment could also be useful to determine if sensitivity or tolerance to environmental stressors is passed down from one generation to the next, providing insights into the species’ ability to adapt to changing conditions and ensure their continued survival.
The study highlights the vulnerability of octopuses to future ocean changes and the importance of understanding how environmental stressors impact marine species. It underscores the need for further research to assess the impacts of climate change on octopus populations and to develop conservation strategies to protect these important marine organisms. By studying the effects of ocean warming on octopuses vision and survival, researchers can better understand the broader implications of climate change on marine ecosystems and work towards mitigating its impacts on vulnerable species.
