What you’re looking at. These are the species confidently identified from environmental DNA collected from Dickey Brook in Blue Mountain Reservation. The MiFishU primer targets fish (and picked up one salamander as a bonus). Western-US co-matches in the raw data have been filtered out as artifacts of the primer’s limited resolution. Click through for deeper info on each.
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American Eel
Anguilla rostrata · 100% match
A snake-like fish that does the unthinkable: born in the Sargasso Sea, drifts as a larva up the Atlantic coast, climbs into freshwater streams (including Hudson tributaries), and spends 10–25 years getting fat on insects and crayfish before swimming all the way back to spawn and die. IUCN lists it as endangered. If you’ve got eels in your brook, that’s a real thing.
Northern Two-lined Salamander
Eurycea bislineata · 100% match
Not a fish, but the primer picked it up anyway and it deserves a card. Small (2–5 inches), yellow-bodied with two dark stripes down the back, and a near-obligate companion of clean, rocky brooks in the Northeast. The larvae are fully aquatic for two to three years before metamorphosing — their presence is a decent water-quality signal.
Bycatch from the fish primer — technically a plethodontid salamander.
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Eastern Blacknose Dace
Rhinichthys atratulus · 100% match
A small (2–3 inch) minnow with a dark lateral stripe running from snout to tail. One of the most common fish in northeastern brooks — if you have a healthy cold-water stream, you almost certainly have these. They’re tolerant of a wide range of conditions but tend to be associated with riffles and gravel.
White Sucker
Catostomus commersonii · up to 100% match
A long, round-bodied bottom-feeder that uses its fleshy down-turned lips to vacuum organic matter, algae, and tiny invertebrates off the streambed. Adults can hit 12–20 inches. Tolerant of turbid water but sensitive to acidification — their skin and liver tumors are used as a Great Lakes water-quality bellwether.
Green Sunfish
Lepomis cyanellus · 100% match
Blue-green back, yellow belly, broken bright blue stripes on the gill cover, and a notably big mouth for a small sunfish. Aggressive, territorial, tolerant of poor conditions, and considered invasive in several states — including parts of the Northeast. Hangs out around submerged logs and rocks.
FishBase · USGS NAS · Wikipedia
Tied at 100% with Bluegill on the same DNA read — the 12S fragment can’t tell them apart, and they hybridize. You likely have one, the other, or both.
Bluegill
Lepomis macrochirus · 100% match
The classic deep-bodied panfish: deep blue and purple on the face and gill cover, olive bands down the side, fiery orange-to-yellow belly, and a dark spot at the back of the dorsal fin. Native east of the Rockies, widely stocked. Eats anything that fits in its mouth.
Fathead Minnow
Pimephales promelas · 100% match
Dull olive-grey with a dusky stripe along the side; breeding males get a strange fleshy growth on the nape and about 16 white bumps on the snout (charming). Famously tolerant of harsh, low-oxygen water, which is why the EPA uses them as a standard toxicology test organism. Often sold as bait or as the rosy-red aquarium morph.
Sequencing and bioinformatics by Jonah Ventures. Identifications from MiFishU 12S eDNA sequencing; western-US co-matches filtered out as primer-resolution artifacts. Images: Wikimedia Commons.