Impacts of an environmental ototoxic pollutant on fish fighting behaviors.

Numerous environmental pollutants exhibit ototoxicity and cause damage to the lateral line structures in fish, including the neuromast and its hair cells. The lateral line is used to detect hydrodynamic changes and is thought to play a significant role in aggressive interactions. Fighting behaviors in fish are crucial for establishing social hierarchy and obtaining limited resources. In this study, we ablated the function of hair cells using a commonly used ototoxin, neomycin, to evaluate the impact of this ototoxic pollutant on fighting behavior through damaging the lateral line. Our results showed that the number of wins and the duration of dyadic fight behavior decreased in zebrafish with lateral line ablation. These zebrafish also exhibited increased anxiety and biting frequencies. On the other hand, social preferences and fitness were not affected in lateral line-ablated zebrafish. In conclusion, the lateral line mechanosensory system is crucial for fish to gather sufficient information and make correct decisions during conflicts and fighting behaviors. Impairment of hair cell function can affect aggressive behaviors and decision-making in fish, subtly altering their behavioral patterns and leading to significant impacts on the aquatic ecosystem.