drifting movement in fishes during migration​

Sourav PanDecember 20, 2024

Answered

Drifting movement is a significant aspect of fish migration, particularly during the early life stages of many species. This passive form of movement allows fish to travel with water currents, facilitating their dispersal and migration across various aquatic environments.

Key Characteristics of Drifting Movement

1. Passive Displacement:
   • Drifting refers to the passive movement of fish, where eggs, larvae, and young fish are carried along by water currents without active swimming. This is crucial for species that spawn in one location but need to reach different habitats for growth and survival.
2. Influence of Ocean Currents:
   • The movement of drifting fish is heavily influenced by oceanographic factors, including the direction and strength of currents. For instance, eggs and larvae will drift along with prevailing currents to reach feeding grounds or suitable habitats where they can develop into juveniles.
3. Directional Movement:
   • Although drifting is passive, it can result in directional movements based on environmental conditions. Fish may drift towards areas that provide better feeding opportunities or suitable spawning grounds as they respond to changes in their surroundings.
4. Life Cycle Stages:
   • Drifting is particularly important during the early life stages of many fish species. Young fish often leave their spawning grounds and drift to nursery areas where they can find food and shelter before returning to adult habitats.

Examples of Drifting Movements

• Salmon: Young salmon drift downstream from their spawning rivers into estuaries and eventually into the ocean, where they grow before returning upstream as adults to spawn.
• Eels: The larvae of eels drift from the Sargasso Sea to freshwater rivers, where they mature before migrating back to spawn in the ocean