Climate Change and the Survival Instinct of Fish

Samantha Zeitz

Climate change is making life for fish a lot more dangerous – this according to scientific studies.

One study published in the journal, Global Change Biology, suggests that the high CO2 levels have begun to affect the normal way of life for a fish. Survival instincts that should send fish swimming away from predators are doing the opposite. When faced with the smell of a potential threat, these fish are swimming towards the predator rather than away. The experts say his is happening because CO2 affects their sensory systems and how they transmit signals to the brain. The fish are even ignoring sound signals that normally tell them the habitat they are approaching could be a threat. It’s believed things will only get worse from here as CO2 level are predicted more than double by the end of the century.

In order to get further information on this phenomenon, experts are looking towards farmed fish. It’s been shown that farmed fish live in conditions that contain 10 times the amount of CO2 compared to wild fish. They say the farmed fish can give them insight into how aquatic species will eventually evolve with climate change.

Climate-change marine biologists at Exeter University, Dr. Robert Ellis and Dr. Rod Wilson say that aquaculture is becoming an “accidental” experiment. By studying organisms that have lived in high CO2 levels for generations they hope to be able to predict the future of wild fish.

This study might not only benefit wild fish, but farmed fish as well. Although farmed fish are supplied their food and don’t have predators to escape from, CO2 still effect their population. CO2 can also reduce digestion efficiency in cod, and small doses can even increase growth.

Dr. Wilson says their research can help fish farmers improve growth, health and maximize profitability. They hope to improve aquaculture sustainability to provide for the ever-growing human population.