The map illustrates the life cycle of salmon, highlighting the key stages of migration and growth between freshwater and marine environments. The process begins in freshwater rivers, where salmon engage in spawning, depositing their eggs on gravel beds. Following a period of incubation, the eggs hatch, and young salmon, known as fry, emerge. These fry undergo freshwater rearing, during which they feed and grow in the river environment.
As they mature, the juvenile salmon migrate downstream to the estuary, a transitional zone where freshwater meets saltwater. Here, they undergo further adaptation to prepare their life in the ocean, a process referred to as estuary rearing.
Upon completing this adaptation, the salmon migrate to the ocean, where they continue to reach maturity. They spend several years in the ocean, accumulating the energy and resources necessary for their return journey.
When the salmon are sexually mature, they initiate their migration back to the estuary and subsequently to their natal rivers. This return to freshwater habitats is driven by an innate homing instinct, guiding them to their original spawning grounds.
The cycle then repeats as the salmon spawn and the next generation begins its journey. This intricate cycle of growth, migration, and spawning ensures the continued survival and regeneration of the salmon population.