Using salmon to understand evolution

Atlantic salmon populations provide us with many ecosystem services, yet spend their lives in two habitats vulnerable to human-driven changes: freshwater and the ocean. Some male salmon are able to reach maturation before migrating from freshwater to the ocean – this is known as early male parr maturation (EMPM).

It is especially common in southernmost Atlantic salmon, suggesting there might be an environmental aspect to this reproductive behavioural trait. The GENEARLY (Genetic determination of early male parr maturation in Atlantic salmon natural populations) research initiative is investigating these salmon in controlled environments to determine the reasons behind the EMPM phenomenon.

Scientists conducted field experiments to identify environmental and genetic factors that are related to early male maturation. During the experiments they controlled certain aspects such as rearing of offspring and genetic crossing in a semi-natural setting.

Researchers found, unexpectedly, that the EMPM trait was largely paternal in nature, which could be due to genetic factors. They are currently determining which genetic markers could be responsible for EMPM.

From this research scientists will develop a better understanding of the environmental effects on salmon and especially EMPM. Such insights into salmon reproduction can lead to improved conservation practices in the face of global change.