Waterfall-climbing fish performs evolutionary feat – Science Nation
♫MUSIC♫ HEIKO SCHOENFUSS: Lots of big waterfalls, and the fish have no problems climbing them. MILES O’BRIEN: These are Inching Climbers. They thrive in the waters of Hawaii. And talk about a fish with an amazing life story! They hatch in streams and are washed out to sea. As juveniles, they head back toward land – facing a gauntlet of predators. Then, to reach the safe haven of their freshwater spawning area, they literally scale waterfalls. What would that climb be like for a human? HEIKO SCHOENFUSS: When we compare to the size of the organism, it’s actually like climbing Mount Everest three times over in a very short period of time! MILES O’BRIEN: With support from the National Science Foundation, Biologist Heiko Schoenfuss of St. Cloud State University and his team study these extraordinary fish. The goal – to better understand how they’ve adapted and evolved – in form and function to accomplish such vertical feats. The inching climber is a species of Gobi Fish. Check out its suckers. That’s how it climbs the waterfall – by suctioning onto the rock behind. HEIKO SCHOENFUSS: So this is an adult Sicyopterus Stimpsoni. We can see the enlarged upper lip and the suction cup that holds onto the surface. It uses an inching up climbing style it advances the head, attaches with the oral sucker, moves the rest of the body upwards and then attaches with the pelvic sucker. MILES O’BRIEN: Key anatomical features show how the fish has adapted to its life cycle. Schoenfuss says understanding how these highly specialized organisms have evolved has implications beyond just one type of fish. HEIKO SCHOENFUSS: The challenge in our case is climbing waterfalls, but it can also be extrapolated to other species, and whether it’s a human induced selective pressure, pollution, or warming of waters, we can learn about how adaptation occurs over long and short periods of time. MILES O’BRIEN: Schoenfuss studies lots of different fish in his lab, but no Inching Climbers – they don’t do well in tanks. But, he and his team go regularly to Hawaii to study them. TAKASHI MAIE: I would like to know more about how physiology of the fish is related to anatomy. So, how much muscle is working, and how harmonious the muscles are with the body movement. MILES O’BRIEN: Schoenfuss also studies how fish in rivers like the Mississippi, near his Minnesota campus, adapt to chemicals in the water. He’s particularly concerned about pharmaceuticals and other bioactive products that we humans let seep into our waterways. HEIKO SCHOENFUSS: Trying to remove them from the water column, trying to keep those chemicals from going into the water in the first place is a really big challenge. MILES O’BRIEN: Maybe not as big a challenge as the harrowing journey of the Inching Climber. Now, that’s taking evolution to… new heights? For Science Nation, I’m Miles O’Brien.