How Fish Swim Upstream

According to a study published in Science magazine, brook trout and other varieties of fish exploit turbulent flows swirling around stationary objects in the water to minimize effort and give themselves an energy-saving boost against the current. By altering their body position and synchronizing movements with the eddies they encounter, says New Scientist, trout save so much energy that they do not have to use their main swimming muscles. “It’s a very low-energy way of moving through a turbulent environment,” explains one of the authors of the study, George Lauder, a biomechanician at Harvard University. In effect, says New Scientist, “the fish were bending their bodies into wing-like hydrofoils to catch the eddies, like a sailboat tacking upwind.”