Young salmon with shorter telomeres — which are typically associated with age — are more likely to survive to make the migration from their river home to the ocean and back, New Scientist reports.
Researchers from the University of Glasgow trapped, tagged, and obtained tissue samples from more than 1,800 young fish as they made their initial migration downstream. As they report in Functional Ecology, the Glasgow team then sampled fish as they made their way back upstream to spawn 1.5 years and 2.5 years later. Unexpectedly, the researchers found that salmon that had shorter telomeres when they initially left their river home were more likely to survive to return to it.
"When we started this project we hypothesized the juvenile salmon with shorter telomeres would have a reduced lifespan and found the complete opposite," Glasgow's Darryl McLennan tells New Scientist.
However, the University of Sheffield's Terry Burke notes that the Glasgow team saw a low rate — 1 percent — of salmon that returned to spawn, though the Norwegian Institute for Nature Research's Kjetil Hindar adds that that's about the rate that he and his colleagues have observed as well, according to New Scientist. Hindar says that far fewer fish have been surviving to make that return migration than used to.