Starhead Topminnow (Fundulus dispar)

Status: State Endangered (1979).

Occurrence: Wisconsin River between Spring Green and Sauk City, lower Sugar River and Coon Creek of the Rock River Drainage, Mukwonago River in Fox River basin, and Black River near LaCrosse. A map outlining Pre-1977 and 1997 to Present Distribution is available.

Aid to ID: Back and upper sides light olive tan, lower sides and belly lighter to yellowish. Series of red to brown dots arranged horizontally along sides. Dorsal fin is mounted far down the posterior end on the back, prominent dark blotch ("teardrop") beneath eye. Adult length: 1.8-2.2 inches (47-55mm).

Habitat: Glacial lakes and clear, well-vegetated floodplain lakes, swamps and marshes. Prefer quiet, clear to slightly turbid (cloudy), shallow backwaters with an abundance of submergent vegetation.

Food Habits: Starheads feed on terrestrial and aquatic insects, crustaceans, mollusks and delicate aquatic vegetation.

Natural History: Occur singly or in pairs just beneath the water's surface, seldom diving deeper even to avoid predators. Spawn in dense beds of aquatic vegetation during late spring to early summer. When placed in unfamiliar locations, starheads have the ability to orient themselves with respect to the sun and attempt to return to familiar waters.

Management Considerations: Watershed management to improve water clarity and reduce sedimentation, or conducting plantings to reestablish necessary vegetation beds for cover and spawning may benefit this species.

Information compiled from publication ER-091.