INFLUENCE OF TEMPERATURE ON FISH PHYSIOLOGY AND BEHAVIOR

Temperature is a key environmental factor influencing fish physiology, metabolism, and behavior, playing a decisive role in the productive performance, health, and survival of aquatic species. With climate change and the intensification of aquaculture, understanding thermal-stress responses has become essential for developing sustainable management strategies and conserving fishery resources. Temperature fluctuations trigger integrated responses that help fish maintain homeostasis under thermal stress. Initially, thermoreceptors detect thermal changes and signal the central nervous system, activating behavioral thermoregulation mechanisms. If exposure persists, the sympathetic nervous system and the hypothalamus-pituitary-interrenal axis are activated, promoting the release of catecholamines and cortisol. These hormones trigger secondary responses, such as hyperglycemia, increased lactate production, intensified branchial ventilation, and cardiovascular and osmoregulatory adjustments. If the stressor persists for extended periods, tertiary responses develop, characterized by reduced growth, impaired immunity, reproductive alterations, lower productive performance, and increased susceptibility to disease and mortality.