Spiny Dogfish
Spiny dogfish are small schooling sharks found along both Canada's Atlantic and Pacific coasts. On the Atlantic side, they're a familiar bycatch and targeted species from the Scotian Shelf to the Gulf of St. Lawrence.
On the Pacific, the closely related North Pacific spiny dogfish (Squalus suckleyi) ranges through BC's shelf waters.
Neither a glamour fish nor a throwaway — dogfish are a legitimate light-tackle and bottom-fishing target, and a serious commercial species exported to European fish-and-chip markets.
Scientific Name: Squalus acanthias
Also known as Piked dogfish, spurdog, spiky dog, spiked dogfish, rock salmon, mud shark, Se ku lah-te (Mi'kmaw)
- Slim, gray or brownish on top with irregular white spots along the sides and back; pale gray to white underneath.
- Two dorsal fins, each with a sharp, mildly venomous spine at the front — the defining feature that separates dogfish from most other small sharks.
- Narrow, pointed snout with small, smooth-edged teeth similar in both jaws — built for gripping slippery prey, not cutting.
- Females grow larger than males; females reach up to about 4 feet, males top out around 3.3 feet. Most fish encountered are well under that.
What to know
Habitat Distribution
- Native to both Canadian coasts: Atlantic populations (Squalus acanthias) range from Labrador south through the Gulf of St. Lawrence, Scotian Shelf, and Bay of Fundy; Pacific populations (Squalus suckleyi) occupy shelf waters throughout BC.
- On the Atlantic side, semi-resident aggregations hold year-round off southern Newfoundland, in the Gulf of St. Lawrence, and on the Scotian Shelf; 10–20% of southwest Nova Scotia fish migrate into US waters in fall and return in spring.
- Found from the surface down to about 730 metres, but most commonly encountered in shallower coastal and shelf waters. Tolerates a wide salinity range and can move into estuaries.
- Prefers cold to cool temperate water; on the Scotian Shelf most commonly caught between 6 and 11°C.
Key Locations
- Scotian Shelf, Nova Scotia — one of the most consistently productive areas for dogfish in Atlantic Canada, with semi-resident year-round populations.
- Gulf of St. Lawrence — another semi-resident aggregation area; dogfish are a common encounter for anglers and commercial fishers throughout the Gulf.
- Southern Newfoundland offshore waters — documented resident aggregations, particularly in summer and fall.
- BC shelf waters — North Pacific spiny dogfish are widely distributed across the continental shelf from the Strait of Georgia to the west coast of Vancouver Island and northern BC.
Specific Spots
- Bottom structure on the continental shelf — gravel, mud, and mixed substrate — where dogfish school in large, sex-segregated groups and work the bottom for prey.
- Mid-water and surface schools form when dogfish are actively chasing baitfish; watch for surface disturbance over schools of herring or mackerel.
- Estuaries and nearshore coastal areas in summer, when fish move inshore following warming water and forage concentrations.
- Deeper offshore shelf edges in winter, as fish move to cooler, more stable depths when inshore temperatures drop.
Spiny Dogfish FAQ
Answers from onWater's species guide.
What are the best lures and bait for Spiny Dogfish?
Cut bait is the standard, fresh or salted herring, mackerel, or squid chunks on a 3/0–5/0 hook. Fresh bait consistently outperforms frozen. Heavy metal jigs (2–4 oz) worked slowly through the water column can draw strikes when dogfish are actively schooling mid-water rather than sitting on the bottom.
When is the best time to fish for Spiny Dogfish?
Summer (June–September): peak inshore fishing as dogfish move into shallower coastal and estuarine waters following warming temperatures and baitfish. Spring (April–May): fish return inshore on the Atlantic coast after winter; good fishing as schools concentrate in nearshore areas.
How do you catch Spiny Dogfish?
Most dogfish fishing in Canada happens from boats, either incidentally while bottom fishing for other species or deliberately with cut bait on bottom rigs over the continental shelf.
What do Spiny Dogfish eat?
Dogfish eat smaller fish, herring, mackerel, sand lance, and juvenile groundfish, as well as squid and invertebrates like shrimp and small crabs. Cut herring or mackerel chunks are the go-to bait because they match what dogfish are already hunting.
Where do Spiny Dogfish live?
Native to both Canadian coasts: Atlantic populations (Squalus acanthias) range from Labrador south through the Gulf of St. Lawrence, Scotian Shelf, and Bay of Fundy; Pacific populations (Squalus suckleyi) occupy shelf waters throughout BC.
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