Appearance Darter describes the darting movements of these small fish that inhabit swift streams. Gilt, meaning gold in color, describes the appearance of adult male gilt darters. During spawning season, males exhibit an iridescent-green upper body and orange-yellow, golden underside from just below the head to the tail. Along the sides, a pattern of dark, square blotches extends from just behind the gill plate to the tail. Colors of the gilt darter vary, depending on age and sex. Females and juveniles are primarily olive brown; their sides have a dark pattern, similar to that of males. Adults typically measure about 3 inches long.
Habitat and Range Gilt darters live in many isolated populations, primarily east of the Mississippi River, from Minnesota to New York in the north, and from Arkansas to Georgia in the south. In Minnesota they have been found only in the St. Croix River drainage. They prefer moderate- to large-size clear streams with strong current. They seek out rocky riffles and other high-flow areas with large cobble raceways.
Biology Gilt darters spawn in spring to early summer. Spawning is triggered by higher water flows and higher stream temperatures, which indicate a change in season. The male stakes out an area with rocks, gravel, and sand that is free of fine particulates such as silt that could suffocate eggs. When a female shows up, the male courts her by displaying his fins and swimming alongside her to coax her into his territory. If the male succeeds in luring her into his breeding ground, the pair then release eggs and milt into a gravel and sand mixture. Fertilized eggs hatch in about a week.
Males can reach sexual maturity in one year, while the slower growing females take two years. Gilt darters can live up to four years, but in Minnesota most gilt darters only make it to their second year -- perhaps a consequence of living on the northern edge of their range.
Status Currently, the gilt darter is classified as a species of special concern in Minnesota. Although the gilt darter can be found in abundance locally in the St. Croix River system, its overall distribution indicates a population in decline, with extirpations in Iowa and Illinois. The decline is primarily due to the darters' intolerance of siltation. Because of this intolerance, the presence of gilt darters indicates good water quality.
Nick Proulx, aquatic biologist
DNR Ecological Resources
The gilt darter occurs in the St. Croix River and some of its tributaries in two of the 25 ecological subsections highlighted in Tomorrow's Habitat for the Wild and Rare: An Action Plan for Minnesota Wildlife. The St. Paul Baldwin Plains and Moraines, bordered by the St. Croix on the east and Mississippi River on the west, contains the gilt darter and nearly 150 other species in greatest conservation need. Wetlands protection and stormwater filtering are needed here to preserve remaining pockets of habitat in this ecological area. Read more about the region and its conservation priorities.