Have you seen the grunt sculpins in the Seattle Aquarium’s Puget Sound Fish exhibit? They’re entertaining to watch because of their awkward way of swimming: they “crawl” on the tips of their finger-like pectoral fins in a series of twitchy hops, jerks and jumps. Despite their poor swimming abilities, they’ve successfully adapted to life in high-current areas—thanks in part to some much-needed help from giant barnacles.
“In the wild, grunt sculpins frequently live in areas where giant barnacles are found,” says the Aquarium’s Curator of Fish and Invertebrates Tim Carpenter. “The barnacles need high water flow to get their food—and grunt sculpins use the barnacles’ shells as protection and egg-laying sites.” In a shrewd act of camouflage, a grunt sculpin will sit in a barnacle shell facing outward. In this position, the shape of its head bears a striking resemblance to the former resident of the shell. “It affords an animal that would have a hard time outrunning a predator a leg up in its environment,” notes Tim.
All animals that have adapted to life in a specific niche can be at risk if anything in that environment changes. That’s definitely the case for the grunt sculpin, which relies on strong, calcareous barnacle shells for protection and reproduction. If a barnacle’s ability to build its shell is hindered due to changing chemistry in the ocean—brought about by ocean acidification, for example—many other species are affected, both directly and indirectly, including the grunt sculpin.
It’s just another strong example of species interdependence, and another reminder to care for and preserve our marine environment. Interested in learning more about grunt sculpins? Visit the Puget Sound Fish exhibit at the Aquarium!