When Atlantic salmon are stopped by dams during their upstream spawning migration, they can deplete needed fat stores, according to research from the University of Maine.
Restoration of critically endangered Atlantic salmon is an important issue in Maine. The population has been declining since the 1800s, according to the researchers. Atlantic salmon return to the rivers from the ocean every spring to swim upstream and spawn in freshwater.
A new study has been performed to quantify the time and energy lost by Atlantic salmon stopped by dams. When the fish are stopped by dams, they are stuck in warmer waters for longer than expected, which can deplete the fat they have stored up to migrate, produce gametes, develop secondary sexual traits and spawn.
“Salmon limit the food they eat in freshwater, so excess energy lost during their migration doesn’t get replaced,” says Sarah Rubenstein, who completed her masters of science in wildlife ecology at the University of Maine in 2021. “Spawning takes a lot of energy, so the more energy reserves salmon have left after migrating and during spawning, the more likely they will be at successfully reproducing.”
