Even slight increases in ocean temperatures may affect a shark’s brain function and cognitive development, according to a study from the Macquarie University Fish Lab.
Researchers found that by raising the temperature of a shark embryo’s environment by 3 degrees Celsius, those that survived had “stronger laterality, suggesting enhanced cognitive abilities.”
“Shark brains are very similar to ours in that they have two hemispheres, each specialised in analysing specific information. Brain lateralisation is like having a dual processor computer: it allows the brain to process information more efficiently,” lead author Catarina Vila-Pouca said.
“Strong lateralisation is associated with enhanced intelligence and is often manifested in behaviour, for example in left- or right-handedness or preference to turn left or right when detouring a barrier,” Vila-Pouca said.
According to the study:
Under predicted end-of-century temperatures, many teleosts show impaired development and altered critical behaviors, including behavioral lateralisation. Since laterality is an expression of brain functional asymmetries, changes in the strength and direction of lateralisation suggest that rapid climate warming might impact brain development and function. However, despite the implications for cognitive functions, the potential effects of elevated temperature in lateralisation of elasmobranch fishes are unknown. We incubated and reared Port Jackson sharks at current and projected end-of-century temperatures and measured preferential detour responses to left or right. Sharks incubated at elevated temperature showed stronger absolute laterality and were significantly biased towards the right relative to sharks reared at current temperature. We propose that animals reared under elevated temperatures might have more strongly lateralized brains to cope with deleterious effects of climate change on brain development and growth.
“They are likely compensating for poor growth due to high temperatures. It is very likely that such changes will affect the way sharks navigate, learn about their environment, and interact with each other,” MUFL Associate Professor Culum Brown said. “This has important implications for survival because it could impact on them finding food, mates and avoiding predators.”
Further research is needed into whether global warming will result in a species of hyper-intelligent sharks in the future.
