1. Marine fish possess distinct osmoregulation mechanisms tailored for high-salinity environments, where ambient salinity exceeds their body’s ion concentration.
2. In marine water, the salinity levels are higher than the fish’s internal ion concentration, necessitating specialized adaptations for osmoregulation.
3. The reverse scenario occurs in fresh water, where the ambient salinity is lower than the fish’s internal ion concentration, making standard marine osmoregulation unsuitable.
4. Due to their specialized osmoregulatory processes, marine fish are unable to survive in fresh water, as their physiological adaptations are not suited for lower saline conditions.