Which risk to fish increases as ambient temperature rises while oxygen levels are already low?

💡 Explanation

As temperature increases, the solubility of oxygen decreases and fish metabolic rate increases; countercurrent exchange in gills becomes less efficient because of reduced oxygen gradient, exacerbating hypoxia. Therefore reduced oxygen uptake results, rather than increased osmoregulatory cost, parasite increase, or digestive difficulty, which are less directly linked to gill function.

• Which outcome is observed when ecdysone secretion inappropriately triggers growth factor signaling among insect imaginal discs?
• Which outcome reduces soaring efficiency when damage disrupts feather alignment?
• Which mechanism causes overheating when an arctic fox increases peripheral vasodilation in summer?
• Which consequence results when increased wing loading in raptors exceeds limits during a static thermal column ascent?
• Which stress response occurs in CAM plants when water availability critically decreases?
• Which circumstance suppresses the C4 carbon fixation pathway?