Fish
Blackside Darter
Percina maculata · also called blackside darters
Resting against a bed of gravel in moderate current, a blackside darter’s row of squarish dark blotches breaks up its outline just enough that a passing predator’s eye slides right over it without ever registering a fish at all.
Overview
The blackside darter, Percina maculata, is a small darter native to stream and river systems across the Great Lakes and Mississippi River drainage basins of central North America. Its distinctive row of dark blotches and preference for moderate-current gravel habitat make it a genuinely useful indicator of healthy stream conditions across its range.
Camouflage measured out in even blotches
Rather than relying on a single solid colour, the blackside darter breaks its own outline into a series of dark, evenly spaced blotches, a pattern that does a remarkably effective job of disappearing against the gravel it spends most of its life resting on.
Status
Least Concern — widespread and stable across suitable stream and river habitat throughout the Great Lakes and Mississippi River drainage basins.
Blackside Darter: common questions
Why is it called the blackside darter?
A blackside darter displays a row of dark, squarish blotches running along its midline, a pattern distinctive enough to give the species its common name and effective enough to help it blend into the sand and gravel substrate it typically rests on.
What kind of stream habitat does the blackside darter prefer?
The blackside darter favours moderate current flowing over sand and gravel substrate, a habitat preference shared with several other darter species found in the same Great Lakes and Mississippi River drainage systems, generally avoiding both very slow, silty water and the fastest, most turbulent riffles.
Why is the blackside darter considered a useful indicator species?
Like many darter species, the blackside darter is sensitive to excess sedimentation and reduced water quality, meaning a healthy blackside darter population can serve as a useful, easily observed signal of good overall stream health within its Great Lakes and Mississippi River drainage range.
Where does the blackside darter live?
The blackside darter is native to stream and river systems across the Great Lakes and Mississippi River drainage basins of central North America, generally favouring sand and gravel substrate under moderate current.