Study identifies genetic link between early maturation and high aerobic performance in juvenile salmon
A study conducted at the University of Helsinki indicates that early sexual maturation and high aerobic performance in salmon have a genetic link that is already evident in juvenile salmon.
Salmon are born in rivers, migrate to the sea to reach maturity and return to spawn in their native river. While salmon that mature at an early age return from the sea after just one year, slower-growing individuals may spend two or more years at sea.
Genomic regions have been identified in the salmon genome that strongly regulate the number of years spent at sea. Led by Academy of Finland researcher Tutku Aykanat, researchers from the University of Helsinki have bred a large number of young salmon that differed based on two of these regions.
The researchers measured the basal metabolic rate and aerobic performance of juvenile salmon before the start of their maturation process. Carriers of genetic variants associated with early sexual maturation were found to have better aerobic performance than those whose variants were associated with late onset of sexual maturity. Aerobic performance refers to the metabolic ability to produce energy through aerobic cellular respiration, for example in muscles.
Better aerobic performance can promote earlier maturation, as growth, food supply and reproduction require energy produced by aerobic metabolism.”
Jenni Prokkola, Postdoctoral Researcher, Faculty of Biological and Environmental Sciences, University of Helsinki
The genetic coupling of age at maturity and performance did not depend on the amount of food available to the salmon, indicating that the finding may be generalizable to both wild salmon populations and farmed conditions.
“Salmon that have spent several years at sea and mature later are considerably larger and produce more offspring when they return to spawn than salmon that spawn after only one year at sea. would be important to determine if these salmon are more sensitive to global warming due to their lower aerobic performance Higher water temperatures increase the energy requirements of fish, but limitations in aerobic performance make it difficult to adapt to high temperatures. Aerobic performance may become an increasingly important factor for salmon in warming habitats,” Prokkola says.
Studying the genetic and physiological factors that influence age at sexual maturity is important to understanding the changes that occur in salmon populations.
Prokkola, JM, et al. (2022) Genetic coupling of life history and aerobic performance in Atlantic salmon. Proceedings of the Royal Society of London B Biological Sciences. doi.org/10.1098/rspb.2021.2500.