Elevated carbon dioxide has limited acute effects on Lepomis macrochirus behaviour

Area of Science:

• Environmental toxicology
• Aquatic ecology
• Fish behavior

Background:

• Rising atmospheric CO2 levels impact aquatic ecosystems.
• Understanding fish responses to hypercapnia is crucial for predicting ecosystem changes.

Purpose of the Study:

• To investigate the behavioral effects of elevated carbon dioxide (CO2) on freshwater fish, Lepomis macrochirus.
• To assess the reversibility of CO2-induced behavioral changes.

Main Methods:

• Lepomis macrochirus were exposed to ambient and elevated partial pressure of CO2 (pCO2) for distinct periods.
• Behavioral metrics including boldness, lateralization, and activity were quantified.
• Individual behavioral consistency was assessed across exposure and recovery phases.

Main Results:

• Elevated pCO2 increased fish velocity and activity in the outer zones of their environment.
• No significant changes were observed in lateralization or most boldness metrics.
• Behavioral disruption occurred during CO2 exposure, with some metrics showing reduced consistency.

Conclusions:

• Elevated CO2 significantly disrupts freshwater fish behavior, particularly activity and movement patterns.
• The observed behavioral changes in freshwater fish were less pronounced than those reported for marine species.
• CO2-induced behavioral disruptions may impact individual performance and population dynamics in freshwater ecosystems.