Why are salmonids dominant in many recently glaciated lakes and streams of the Northern Hemisphere?

Salmonids are dominant in many recently glaciated lakes and streams of the Northern Hemisphere primarily due to the development of an anadromous life cycle.1

By spawning in fresh water but migrating to the sea for feeding and maturation, species of trout and salmon can effectively bypass the limitations of purely freshwater environments. This strategy provides marine invasion routes that allow for the rapid expansion and colonization of new areas—such as those made inhabitable by receding glaciers—that are often inaccessible to fish species restricted to a strictly freshwater life cycle.1

Additionally, the generalized, non-specialized morphology of salmonids allows them to utilize diverse ecological niches, while their powerful swimming ability enables them to navigate strong currents and overcome physical barriers like waterfalls.23