Chronic Boat Noise Impacts on the Early Life Stages of Cichlids (Maylandia zebra): Preliminary Findings

Anthropogenic noise is globally recognized as a stressor for animals. However, despite evidence of detrimental effects of noise exposure on fish, knowledge about chronic effects on critical early life stages is still scarce. Using a split-brood design to exclude the genetic effect, African cichlids (Maylandia zebra) from the same brood were exposed to boat noises (~120 dB) and to control condition (~100 dB) for 12 weeks, starting when mouth-brooding females released their young. Treatment fish were exposed to motorboat noises from 9 a.m. to 6 p.m. to mimic a typical daily boating activity. Larvae total length and foraging activity were measured in weeks 1 and 12. The study did not find a significant effect of chronic boat noise exposure on these variables. However, whether noise has any impact within the studied period or after week 12 is not clear. Future work will focus on analyzing the data weekly over the 12 weeks exposure period to further substantiate the current results. Addressing the effect of anthropogenic noise on early life stages may have implications for our understanding of the effect of this pervasive stressor on aquatic organisms.