Adaptive Advantages of Invasive Mosquitofish Over Native Medaka in a Warmer, Hypoxic World: Comparative Physiological and Transcriptomic Insights

This study investigates the mechanisms underlying the hypoxia tolerance of the invasive western mosquitofish (Gambusia affinis) compared to the native Chinese medaka (Oryzias sinensis) in the context of increasing urbanization and climate change. Freshwater ecosystems, essential for biodiversity and human well-being, are being severely impacted by multiple stressors, especially in urban areas where the urban heat island effect and extreme climate events exacerbate hypoxic conditions. The rapid spread of G. affinis, which has led to the decline of native species like O. sinensis, may be due to its superior ability to cope with hypoxic environments. By evaluating hypoxia tolerance through aquatic surface respiration and loss of equilibrium, and conducting comparative transcriptomic analysis under normoxic and acute hypoxic conditions, this study aims to uncover the molecular and physiological strategies that enable G. affinis to thrive in increasingly volatile environments, offering insights into the broader implications of invasive species proliferation in a warming world.