Fish migrate for various reasons, such as fulfilling their life cycle, spawning, responding to unfavorable environmental conditions, avoiding predators, searching for food, and seeking suitable areas for survival (Kantun & Mallawa, 2016). Migration is a link in the life cycle that cannot be separated from the links before and after it.
Fish migrate to areas where they find the conditions necessary for a particular phase of their life cycle. Migration aims to adapt, ensuring favorable conditions for the species’ existence and reproduction. Fish migration is usually active, but sometimes passive, moving from one habitat to another (Nikolsky, 1969).
Migration is considered when fish move relatively regularly and in groups from one place to another to fulfill their life cycle needs. Sometimes migrations must be made over very long distances during certain seasons. Several fish species known as highly migratory species include tuna (Thunnus), marlin (Makaira, Tetapturus), sailfish (Istiophorus), and swordfish (Xiphias).
Based on their purpose, migration is classified into three types: spawning migration, foraging migration, and refugee migration. Spawning migration or reproductive migration is related to fish spawning. Foraging migration is related to food, while refugee migration occurs when their habitat changes, making it unsuitable or dangerous.
Fish can detect adverse environmental conditions or dangers, potentially migrating to escape. Fish’s bodies detect environmental changes because they are equipped with sensory receptors, both physical and chemical.
