Blacknose Dace
Characteristics
Brownish to black above, and speckled sides with dark scales giving the fish a mottled look. A dusky lateral band is outlined above by a row of light scales. Spawning males develop a pink to red-colored lateral band. The sub-terminal mouth is oblique with equal jaws, and a barbell is on the posterior tip of the lower jaw. The upper lip is attached to the snout without a groove (a feature know as a frenulum), which is characteristic of Rhinicthys. There are 62 to 71 scales in the complete lateral line. Hooked pharyngeal teeth are arranged in a formula of 2, 4-4, 2. The peritoneum is silvery-colored, and the air bladder is well developed. Dorsal and pelvic fins have 8 rays, while the anal fin has 7, and the pectoral fins have 13 to 16 rays.
Distribution
The Blacknose Dace is common throughout central and northeast Iowa, with scattered populations also found in the Little Sioux River, Big Sioux River, Rock River and Floyd River drainages. It is absent from southeast Iowa. The distribution of the Blacknose Dace in Iowa is increasing, especially in northeast Iowa rivers (Eastern Broadleaf Forest Aquatic Subregion).
Foods
Aquatic insects and larvae.
State Record
Grows up to 4 inches. State Records are not documented for non-game species.
Expert Tip
Blacknose Dace are sometimes called the "riffle daces" because they prefer clear waters with swift currents over a rocky substrate, which explains their thriving in Iowa's trout streams.
Details
Spawning takes place from May through July, when males build a nest of gravel and guard a well-defined territory. Eggs are 1/6 to 1/8 inch in diameter. Young Blacknose Dace are 1 1/2- to 2-inches long by the end of the first season. Adults reach up to 4-inches long.
The Blacknose Dace was first listed as the Western Blacknose Dace (Rhinichthys Atratulas Meleagris), which is probably the correct interpretation for this minnow in Iowa.
The Blacknose Dace prefers clear, cool headwater and medium-sized streams over gravel bottoms. It is common in moderate to fast flowing water and appear to reach its greatest abundance in trout streams, such as in northeast Iowa.
The Blacknose Dace has a growing population and is viewed as secure according to the Iowa Wildlife Action Plan.
Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.
Sources:
Harlan, J.R., E.B. Speaker, and J. Mayhew. 1987. Iowa fish and fishing. Iowa Conservation Commission, Des Moines, Iowa. 323pp.
Iowa Department of Natural Resources, Iowa Wildlife Action Plan
Loan-Wilsey, A. K., C. L. Pierce, K. L. Kane, P. D. Brown and R. L. McNeely. 2005. The Iowa Aquatic Gap Analysis Project Final Report. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames
Illustration by Maynard Reece, from Iowa Fish and Fishing
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