Freshwater Fish Migration: Fisheries Management Strategy Insight

Migration is a deliberate movement taken by animals for survival. It is commonly categorized as spawning, feeding, and refuge seeking migrations. Migration is governed by costs and benefits. Energy production and utilization is one of the greatest challenges of freshwater fish migration. The upstream and long-distance migrants demand more energy. Orientation and navigation mechanisms in fishes have a long history of interest. Different sensory mechanisms for accurate orientation have been suggested, including orientation using sun position, polarized light patterns, and the Earth's geomagnetic field. Fish morphology plays a significant role in assisting freshwater fish's migration. Long-distant migrants have streamlined body structure and longer caudal regions, while short-distance migrants are fusiform making them hard to move long distance against water current. Since fish migration may involve two different aquatic environments, all migrant fishes that cross the interface between freshwater and saline water habitats must therefore undergo physiological changes. Fish migration activities are influenced by abiotic factors including variations in water temperature, water level, and light availability. Human activities significantly affect fish migration. A good understanding of the migratory behavior of fishes is important for effective fisheries management. Fishermen and near-shore communities need to become aware about the nature of fish migration.