Imagine you're sitting by the shore. Suddenly, something jumps out of the water. Then another!
It's Salmon. And maybe they're just showing off. Or avoiding something? Or maybe they're shaking off sea lice.
Sea Lice
Scientists noticed that young sockeye salmon jump out of the water and skim its surface with their tails an average of nine times a day, and it‘s clear they‘re not just leaping over obstacles. Researchers had a hunch the salmon were trying to get rid of sea licesince it‘s known that fish with sea lice jump out of the water fourteen times more often than fish that are sea lice-free.
A sea louse is a parasite about the size of a pea that feeds on mucus, blood, and skin. So, it makes sense why salmon want to get rid of them.
Jumping Salmon
Scientists wanted to find out though, does the jumping actually help? They caught salmon infested with sea lice and divided them into two groups.
They put one into an ocean pen where they could leap out of the water, and another into a pen with netting covering the water‘s surface. After three days, the salmon that couldn‘t jump out of the water had twenty-eight percent more sea lice than the ones that could.
It works eventually—but it takes them an average of fifty-six jumps to dislodge one sea louse.
Thank you to John Reynolds, Emma Atkinson, and Sean Goodwin of Simon Fraser University for reviewing this episode's script.