Elevated carbon dioxide has the potential to impact alarm cue responses in some freshwater fishes

Abstract

Freshwater fish behaviors have the potential to be impacted by acidification due to increases in dissolved carbon dioxide (CO2). Recent work in the marine environment suggests that increased CO2 levels due to climate change can negatively affect fishes homing to natal environments, while also hindering their ability to detect predators and perform aerobically. The potential for elevated CO2 to have similar negative impacts on freshwater communities remains understudied. The objective of our study was to quantify the effects of elevated CO2 on the behaviors of fathead minnows (Pimephales promelas) and silver carp (Hypophthalmichthys molitrix) following exposure to conspecific skin extracts (alarm cues). In fathead minnows, their response to conspecific skin extracts was significantly impaired following exposure to elevated CO2 levels for at least 96 h, while silver carp behaviors were unaltered. However, fathead minnow behaviors did return to pre-CO2 exposure in high-CO2-exposed fish following 14 days of holding at ambient CO2 levels. Overall, this study suggests there may be potential impacts to freshwater fishes alarm cue behaviors following CO2 exposure, but these responses may be species-specific and will likely be abated should the CO2 stressor be removed.