* Oxygen Solubility: Warmer water holds less dissolved oxygen than colder water. This means the fish has to work harder to extract the same amount of oxygen from its surroundings.
* Metabolic Rate: Higher temperatures increase the fish's metabolic rate, meaning their cells need more oxygen to function.
* Gill Efficiency: Warm water can also affect the efficiency of the gills, making it more difficult for the fish to extract oxygen.
In short, warmer water creates a situation where fish need more oxygen but have less available, leading to an increased breathing rate.
This is a significant factor in the impact of climate change on fish populations, as rising water temperatures can make it difficult for fish to survive, especially in areas with already low oxygen levels.