Painted Goby Larvae under High-CO2 Fail to Recognize Reef Sounds

Atmospheric CO 2 levels have been increasing at an unprecedented rate due to anthropogenic activity. Consequently, ocean p CO 2 is increasing and pH decreasing, affecting marine life, including fish. For many coastal marine fishes, selection of the adult habitat occurs at the end of the pelagic larval phase. Fish larvae use a range of sensory cues, including sound, for locating settlement habitat. This study tested the effect of elevated CO 2 on the ability of settlement-stage temperate fish to use auditory cues from adult coastal reef habitats. Wild late larval stages of painted goby ( Pomatoschistus pictus ) were exposed to control p CO 2 (532 μatm, pH 8.06) and high p CO 2 (1503 μatm, pH 7.66) conditions, likely to occur in nearshore regions subjected to upwelling events by the end of the century, and tested in an auditory choice chamber for their preference or avoidance to nighttime reef recordings. Fish reared in control p CO 2 conditions discriminated reef soundscapes and were attracted by reef recordings. This behaviour changed in fish reared in the high CO 2 conditions, with settlement-stage larvae strongly avoiding reef recordings. This study provides evidence that ocean acidification might affect the auditory responses of larval stages of temperate reef fish species, with potentially significant impacts on their survival.