Witch Flounder
Witch flounder are a deepwater flatfish of Canada's Atlantic coast, caught mainly as bycatch in the commercial groundfish trawl fishery across the Scotian Shelf, Gulf of St. Lawrence, and Grand Banks.
Recreational anglers rarely target them directly — their preferred depths of 100–400 metres put them well beyond typical inshore reach — but they're a valued table fish when they do come up.
Scientific Name: Glyptocephalus cynoglossus
Also known as Grey sole, plie grise
- Right-eyed flatfish with a distinctively narrow, elongated oval body — slimmer and more elongated than most other Atlantic flatfish species.
- Eyed side is dark grayish-brown; blind side is grayish-white with tiny dark dots scattered across it.
- The pectoral fin on the eyed side is noticeably dusky to black with a thin pale border — a reliable field mark that separates witch flounder from similar species.
- Grows to roughly 75 cm and about 4 kg; females grow larger and live longer than males, which rarely exceed the size of females.
What to know
Habitat Distribution
- Native to the Northwest Atlantic; in Canada, found from southern Labrador south through the Gulf of St. Lawrence, Scotian Shelf, and Grand Banks.
- A deepwater species — most fish live at 100–400 metres, though individuals have been recorded as deep as 1,600 metres.
- Strongly tied to soft bottoms: sand, clay, and mud substrates, particularly in deep holes, channels, and along the shelf slope.
- Prefer cold water, typically 2–6°C, and show little evidence of large-scale seasonal migration — local movements are mainly tied to spawning concentrations.
Key Locations
- Grand Banks (2J3KL, 3NO) — historically the core of Canadian witch flounder abundance, now under active stock rebuilding efforts.
- Scotian Shelf — supports a managed commercial fishery; spawning concentrations peak in summer in deeper shelf waters.
- Gulf of St. Lawrence (4RST) — a distinct management unit with its own stock assessment history under DFO.
- Southern Labrador and Eastern Newfoundland shelf slope — northern edge of the Canadian range, with fish concentrated in deep channels.
Specific Spots
- Deep holes and channels on the Scotian Shelf and Grand Banks are where commercial trawlers find the highest concentrations.
- Shelf slope edges where soft mud transitions to deeper water hold fish year-round, as witch flounder don't make the inshore migrations that other flatfish do.
- On the Grand Banks and in the Gulf of St. Lawrence, fish concentrate in deeper basins during summer spawning periods.
Witch Flounder FAQ
Answers from onWater's species guide.
What are the best lures and bait for Witch Flounder?
Sea worms and cut bait on bottom rigs are the most reliable options, witch flounder's small mouth and worm-focused diet make them poorly suited to lures. A simple two-hook bottom rig with enough weight to stay planted on soft mud at depth covers most situations where these fish are encountered.
When is the best time to fish for Witch Flounder?
Summer (July–August), peak spawning period on the Scotian Shelf; fish concentrate in deeper shelf waters during this window. Year-round commercial fishery operates across managed areas, subject to DFO quota and area restrictions.
How do you catch Witch Flounder?
Witch flounder in Canada are caught almost exclusively by commercial trawlers working soft-bottom grounds at depth on the Scotian Shelf and Grand Banks.
What do Witch Flounder eat?
Feeds primarily on bottom-dwelling worms (polychaetes) and small invertebrates living in soft mud, their small mouth is built for picking prey off and out of the substrate rather than chasing baitfish.
Where do Witch Flounder live?
Native to the Northwest Atlantic; in Canada, found from southern Labrador south through the Gulf of St. Lawrence, Scotian Shelf, and Grand Banks. A deepwater species, most fish live at 100–400 metres, though individuals have been recorded as deep as 1,600 metres.
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