Understanding Changes in Migration Timing in Scotland's Atlantic Salmon

Atlantic salmon are an important component of northern freshwater ecosystems.

Salmon are born and spend their first years in freshwater; they then migrate to the ocean to feed and grow before returning to their natal site to breed.

This creates a vital ecological link that spans headwater streams to the high seas, and changes in salmon return to freshwater can be a barometer for conditions in the less easily observed ocean.

Elements of a salmon's life history, such as time spent at sea, are recorded in its scales which also yield DNA for genetic analysis.

Understanding the drivers and mechanisms of these run-timing changes will improve our understanding of why Atlantic salmon are declining overall, and thus help shape strategies for their conservation.

The successful PhD candidate will work towards this aim by: identifying watershed characteristics that shape variation in the run-timing phenotype; relating recent historical variation in adult age and return timing to changes in the North Atlantic marine food web, using an established framework; relating known run-timing genes to specific migratory strategies, and identifying additional genes that may be important; and investigating whether recent changes in run-timing are the result of phenotypic plasticity or selection on these underlying genes.