Climbing Waterfalls

Disa Woodland, Copy Desk Chief~

Dr. Takashi Maie, an assistant professor of Biology at Lynchburg College, has been pursuing research into the functional morphology of the Goby fish in Hawaii and his native Japan.

The Goby fish, also referred to as the waterfall climbing fish, use a sucking action coupled with the contraction of muscles attached to their vertebrae to climb up waterfalls.At the top of the waterfall, the Gobies find freshwater. This is necessary for them to mate and spawn eggs, after which they return to the sea. Gobies can be found upstream of waterfalls on volcanic islands. They are, however, not the only types of fish who have evolved to find a way back to the freshwater from whence they came.

Maie is interested in the musculoskeletal system of vertebrates. Maie’s teaching at LC focuses on human anatomy and physiology but for research purposes has advanced to exploring the waterfall-climbing fish species of volcanic islands.

Photo of a Goby and an example of its habitat provided by Dr. Takashi Maie. This photo was also published by National Geographic.

The Goby provide a sustained pool of research subjects; they remain unendangered. As vertebrates, they possess similar bio-mechanics to humans. Maie’s research involves first capturing Gobies, simulating the conditions encountered at a waterfall and using a pressure plate to measure the force exerted by the suction of the mouth as well as the contractions of the muscles.

The question to be answered was how the force exerted for climbing was changing as the size of the Goby increased with age. Gobies, when fully grown, can exert a force about five times their weight to aid in the return to freshwater. Suction force changes as muscle fatigue is experienced, and that is one of the other aspects of Maie’s research, exploring the effects of muscle fatigue on suction force. Thus far, it appears that the suction force is used to maintain the fish’s place on the waterfall until the vertebral muscles recover and can be used to move up the waterfall once more.

The waterfall-climbing fish found in and around the volcanic islands of Hawaii and Japan, including the Goby but not limited to the Gobiidae species, possess two styles of climbing; power burst and inch-up. The Goby use the power burst style.

An interesting discovery is that, around the globe, where waterfalls can be found, there exists unrelated species of fish who use either method for the same purpose, returning to the freshwater source upstream in order to mate and spawn. This is of interest because of the evolutionary aspects and implications of such behavior.

It is unknown whether there has been a possible intermingling of certain genetic traits as the Goby and other fish find their way out to sea or if the characteristic developed from a need to return to freshwater to continue the species.