Y: Did you see that, Don? That thing that just jumped out of the water? There’s another one, look!
D: I think they’re salmon, Yaël.
Y: I think they’re showing off.
D: Maybe… or maybe they’re shaking off sea lice.
Y: I’m guessing you know something about these salmon that I don’t know.
D: Well, I know that 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 lice since it’s known that fish with sea lice jump out of the water fourteen times more often than fish that are sea lice-free.
Y: Remind me what a sea louse is?
D: A parasite about the size of a pea that feeds on mucus, blood, and skin.
Y: Makes sense why salmon want to get rid of them. Does jumping actually do the trick?
D: That’s what scientists wanted to find out. 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.
Y: So they figured out something that works.
D: It works eventually—but it takes them an average of fifty-six jumps to dislodge one sea louse.Y: Not the best stats. They should really work on their technique.