Clingfish could inspire better medical devices, whale tags

Other animals can generate similar levels of suctioning forces, but few can do so in wet and slimy environs -- and with such speed and efficiency.

By Brooks Hays

SEATTLE, May 4 (UPI) -- The Puget Sound's Northern clingfish is scaleless, slimy and slender. It's muddled appearance makes it mostly unassuming. But researchers are intrigued by its impressive suctioning ability.

The fish, which looks like an enlarged tadpole and can be found scuttling about the shallows of the Pacific, can generate a suction force capable of holding 150 times its own body weight. What's more, the fish's suction grip works best on uneven surfaces in wet and slimy environs.


Scientists at the University of Washington have been studying the Northern clingfish to better understand the biomechanics of its impressive suctioning skills -- with hopes of mimicking the process in the medical field.

"Northern clingfish's attachment abilities are very desirable for technical applications, and this fish can provide an excellent model for strongly and reversibly attaching to rough, fouled surfaces in wet environments," explained Petra Ditsche, a postdoctoral researcher at Washington's Friday Harbor Laboratories on San Juan Island.

The clingfish's suctioning power is produced by its belly not its mouth. A suctioning disc on the flat-headed fish's underside features layers of tiny hairlike structures that can be deployed to grip surfaces of varying roughness.


"Moreover, the whole disc is elastic and that enables it to adapt to a certain degree on the coarser sites," Ditsche added.

Other animals can generate similar levels of suctioning forces. Spiders and lizards, for example, can scale walls and hang walk across ceilings. But these creatures don't perform in wet environments. Other sea-bound animals, like starfish and sea urchins, can also hold to objects with impressive force.

But the clingfish sets itself apart with its ability to quickly grip and release. Whereas a starfish takes a fair amount of time to release and move to a new location, the Northern clingfish can release its hold in a matter of seconds.

This ability could be particularly useful if researchers can find a way to integrate it into medical devices used in surgery.

"The ability to retract delicate tissues without clamping them is desirable in the field of laparoscopic surgery," lead researcher Adam Summers said. "A clingfish-based suction cup could lead to a new way to manipulate organs in the gut cavity without risking puncture."

Summers and his research team say the fish's clinging mechanics could also help scientists design more effective whale-tagging devices.

The team presented the latest science on the fish's suctioning power at last month's annual Adhesive and Sealant Council Annual Meeting, held in Nashville.


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