The Streamline Chub (Erimystax dissimilis) was described in 1840 by Ohio naturalist Jared Potter Kirtland. The name Erimystax means "a lot of mustache," referring to the thick stripe that wraps around their snout. dissimilis means "dissimilar," most likely describing the spots on their sides. These fish fall into the Family of minnows and shiners, which for North America has roughly 320 unique species!
Fortunately, the subject for our article is not just some "shiny thing," but have unique characteristics that set them apart from their cousins. Streamline Chubs are identified by their long, slender bodies which are nearly rounded in cross-section, having a small barbel in the corner of their mouth, and 7-11 dark dashes along the sides. They have been recorded to reach a maximum length of 14 cm (~5.5 in).
A large Streamline Chub from the Walhonding River, OH.
Streamline Chubs typically reside in medium and large rivers but have been found outside those confines. The ideal habitat is defined by swift, flowing water over gravel beds. During the day, Streamlines can be found cruising around in one to four feet of water. These areas will serve as the hub for all life-stages and provide the essentials for our little swimming friends.
Video showing a small school of Streamlines in the Little Darby Scenic River, Georgesville, OH.
Streamline Chubs have multiple feeding strategies that help them survive day-to-day, but they all revolve around insects. One being they feed on algae that grows on various submerged surfaces. Here they can obtain different aquatic insects like mayflies, caddisflies, and midges. Another is where they search crevices made between the rocks. The final is a relationship with other fishes known as commensalism, which means one organism benefits and the other does not but is unharmed. This behavior has been observed where a school of Streamlines will follow larger fish, say a Northern Hogsucker, and eat from the water column after the other sifted and kicked up the sediment.
Being a minnow of moderate size, they will often fall prey to multiple animals. Most of their aquatic predators include Smallmouth Bass, Northern Pike, Longnose Gar, and other larger species. This is why they often get used as baitfish by anglers for their "sportfish." From the land, they can be picked up by Herons, Kingfishers, and Water Snakes.
A specimen from the middle reaches of the Scioto River, Ohio.
The spawning behavior for Streamline Chubs is not as well known compared to the species we have covered here before. It is assumed that they are broadcast spawners that disperse their eggs across gravel beds in the Spring and early Summer. Maybe this year I'll be able to observe this little-known behavior.
Unlike most of our other covered species, the Streamline Chub has a small distribution range. As shown on the image above from Fish Map, it extends from southern New York down to northern Alabama, following the western slope of the Appalachian Mountains, with an isolated watershed in the Kankakee. They are of "least concern," but that does not mean they are invincible when it comes to human or natural causes. Streamlines are highly intolerant of pollution and require silt-free substrates of cobble, gravel, and sand. Because of this, they can be considered an indicator species of stream health.
The best observation methods are to fish for them and to go underwater. When describing this species, Kirtland stated that they are known for readily taking hook-and-line. Using light line and a small hook, with a chunk of red worm, weighed down with split shot in faster water will get your bait in front of one. Grabbing a snorkel mask and tube on a hot summer day will not only cool you off but also put you face-to-face with an interesting little fish. No matter how you choose to observe them, make sure you continually enjoy, protect, and enhance our freshwater habitats!
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