Genetic testing has confirmed the presence of a new fish species in the Coeur d’Alene and St. Joe rivers.
Cedar sculpins are small, prehistoric-looking and tasty to trout. For decades, fisheries biologists thought the minnow-sized fish were a more common variety known as the shorthead sculpin.
But after scientists detected subtle variations, they sent fish tissue samples to a Missoula lab for testing. The discovery of the new species was a collaborative effort between the University of Montana and the U.S. Forest Service.
“The average person wouldn’t be able to tell the difference,” said Michael Young, a Forest Service fish biologist. “One of the physical differences is visible only if you dissect the fish. The other involves the placement of pores right before the tail. What tipped us off to this being a new species … was the genetic work.”
Sculpin are found throughout North America’s major river systems. They’re an important prey fish for trout and salmon, and an indicator of cold, clean water.
In the Inland Northwest, cedar sculpin probably emerged as a distinct species thousands of years ago, Young said. The falls on the Spokane River would have blocked fish passage and cut off access to other sculpin populations.
Mottled brown-and-white coloring helps camouflage cedar sculpin, making them more difficult for bigger fish to detect. Their ancient look comes from elongated, snaky bodies and feathery fins. They’re nocturnal bottom-dwellers and seldom grow longer than 4 inches.
In addition to the Coeur d’Alene and St. Joe rivers and their tributaries, cedar sculpin have been found in Hayden Creek and a small part of the Clark Fork River. They may be in the upper Spokane River, too.
Since cedar sculpin are found in the Coeur d’Alene Tribe’s ancestral homelands, Young invited tribal elders to provide the scientific name, which is Cottus schitsu’umsh (pronounced s-CHEET-sue-umsh.)
Schitsu’umsh means “those who were found here” in the Coeur d’Alene language, and it’s the tribe’s name for itself. Cottus is part of sculpin’s scientific classification.
Cedar sculpin was chosen as the fish’s common name because Western red cedar are found in the fish’s streamside habitat.
Though cedar sculpin are abundant in local streams, Young said they shouldn’t be taken for granted. They’re an indicator of water quality and stream health.
“If you’re in a trout river with a lot of big fish, they’re probably feeding on sculpin,” he said.
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