head and anterior flattened dorso-ventrally; terminal mouth with numerous teeth in narrow bands on the upper and lower jaws; two lobed, narrowly connected dorsal fins; head, back, and sides olive brown with dark mottling; lower region of head and belly lighter to whitish
northeast Iowa trout streams
larval aquatic insects, invertebrates
The mottled sculpin is an inhabitant of northeast Iowa trout streams. It is somewhat less common than the slimy sculpin and is found in warmer waters. Mottled sculpin are found in streams with an average water temperature of 68 degrees F (range 6l to 72 degrees F).
The head and anterior body of mottled sculpin are flattened dorso-ventrally with the posterior body and caudal peduncle compressed laterally. The mouth is terminal and contains numerous teeth in narrow bands on both jaws. It has two dorsal fins that are narrowly connected; the first has 6 to 9 soft spines and the second has 17 to 19 rays. The anal fin contains 13 to 15 rays, the pelvic fin is thoracic with one spine and 4 rays, and the pectoral fin has 14 to 15 rays. Scales are absent along the incomplete lateral line ending under the second dorsal fin. The back and sides are brown to tan with dark mottling, and the lower region of the head and belly are whitish. This fish averages 3 to 4 inches in length.
The mottled sculpins` behavior and feeding habits are quite similar to the slimy sculpin. It can modify its body colors to match the background which helps it escape predation and may be useful in ambushing food items.
The mottled sculpin has often been called a "trout indicator" and usually where there are sculpin populations, the water generally holds trout as well. Trout fishermen sometimes use mottled sculpins for bait when they are fishing for large brown trout.