Pink Salmon Struggle as Freshwater Becomes Acidic

Pink salmon are providing researchers with sobering hints to how carbon dioxide-induced acidity could affect freshwater fish species by the end of the 21st century.
A study published yesterday in Nature Climate Change showed that early exposure to high levels of CO2 during the larval stage of development had significant negative effects on the fish’s size, metabolism and ability to sense threats in their environment. After obtaining salmon embryos from a hatchery, the researchers transferred them into freshwater flow-through tanks with either ambient, high or variable concentrations of CO2. After 10 weeks, they tested the baby fish to see whether or not their development had been affected by the different conditions.
They found that not only were they smaller and lighter, but the fish’s senses were also impaired. The pink salmon larvae were more bold around new objects and did not seem to be afraid of alarm cues in the water that would normally prompt fish to flee.