How far can Atlantic salmon migrate?

Atlantic salmon migrate an impressive distance during their lifetimes, primarily to complete their complex lifecycle. These highly adaptable fish are known for undertaking arduous journeys from their natal rivers to diverse habitats in the open ocean and back again. Depending on their specific population, Atlantic salmon can migrate thousands of kilometres (miles), making them one of the most extensive migrants among fish species. Here are some notable migration patterns of Atlantic salmon:

1. Home River Migration:

Atlantic salmon are semelparous, meaning they reproduce only once before they die. After spending their early life stages in freshwater rivers, where they hatch from eggs and develop as juveniles, young salmon undergo a process called "smoltification." During this period, physiological changes prepare them for life in the ocean. Once ready, they migrate downstream towards the sea, marking the beginning of their extended migration journey.

2. Oceanic Migration:

Upon entering the ocean, Atlantic salmon embark on an extensive journey that varies in distance and duration depending on their stock and the specific ocean basin they inhabit. These migrations take them across vast expanses, even crossing the North Atlantic Ocean between North America and Europe. In the ocean, salmon feed, grow, and undergo further maturation until they reach sexual maturity.

3. Feeding Grounds and Distribution:

During their time in the ocean, salmon roam widely and can travel great distances in search of suitable feeding grounds. For instance, some populations of Atlantic salmon from North America migrate to the waters off Greenland and the Norwegian Sea to feed on abundant prey, including herring, capelin, and other fish.

4. Return Migration:

When Atlantic salmon reach sexual maturity, they undergo another remarkable migration, commonly referred to as the "return migration" or "spawning migration." Guided by their extraordinary sense of smell, salmon navigate back to their natal rivers, where they were born, to reproduce. This journey can involve swimming upstream against strong currents and overcoming obstacles such as waterfalls and rapids, demonstrating their resilience and determination to fulfil their life cycle.

5. Distance Covered:

The distance travelled by Atlantic salmon during their migrations varies greatly depending on their specific population and migration routes. Some populations may undertake migrations spanning thousands of kilometres (miles), while others may cover shorter distances. For example, Atlantic salmon from the Baltic Sea migrate shorter distances compared to those from North American rivers that cross the entire North Atlantic Ocean.

In summary, Atlantic salmon undertake extensive migrations during their lifetimes, primarily to complete their life cycle. They migrate from their natal rivers to the open ocean, where they may travel great distances before returning to their home rivers to reproduce, thus demonstrating remarkable navigational abilities and endurance throughout their remarkable journeys.