Species

Spiny dogfish

A slender grey shark with white spots and a venomous spine in front of each dorsal fin, called spurdog in Britain. Heavily overfished in the northeast Atlantic: release every spurdog with care.

Squalus acanthias

Photo: Doug Costa, NOAA/SBNMS, Wikimedia Commons, Public domain, adjusted to 3:2

Spawning: Live-bearing (ovoviviparous): gestation 18 to 24 months, the longest known of any cartilaginous fish, litters of 1 to 21 pups of 18 to 30 cm (FishBase). In the northeast Atlantic pups are born in winter at about 26 to 28 cm (FishBase). Males mature at 60 to 70 cm, females at 75 to 90 cm (FishBase); according to English Wikipedia males at about 10 and females at about 16 years.
Typical method: Boat fishing on the bottom with fish strip, especially in Norway, Scotland and Ireland (rule of thumb)
Top bait: Mackerel strip

Plan a day fishing for Spiny dogfish

How to recognise it

Slender shark body, back and sides bluish grey to brown with irregular white spots, pale belly
A sharp spine with a venom gland in front of each of the two dorsal fins
No anal fin; pointed snout, tail with a larger upper lobe

Easily confused with: Catsharks (for example the lesser spotted dogfish) have dark spots, an anal fin and no dorsal spines (rule of thumb). The tope (Galeorhinus galeus) also lacks spines and has an anal fin (English Wikipedia, tope). Note: the German name "Hundshai" (tope) is regionally also used for the spurdog (GBIF).

How to catch it

Methods: Boat fishing on the bottom with fish strip, especially in Norway, Scotland and Ireland (rule of thumb), Drifting with natural bait over sand and mud (rule of thumb), Wire or heavy mono leader because of the sharp teeth and rough skin (rule of thumb), Unhook in the water or with a wet towel, keep hands away from the spines (rule of thumb)

Baits: Mackerel strip, Herring strip, Squid, Small whole baitfish, Sandeel

Spurdogs travel in schools sorted by size and sex (FishBase); catch one and there are often more around. In tagging studies North Sea spurdogs moved to Norway in winter and to Scotland in summer (FishBase).

Habitat and food

Worldwide in cool and temperate seas except the North Pacific, where records refer to Squalus suckleyi (FishBase). Lives on the shelf and upper slope, usually at 50 to 300 m, known from 0 to 1,978 m; adults mainly at 10 to 200 m, mostly near the bottom but also in midwater and at the surface (FishBase). Tolerates brackish water and enters bays and estuaries. Tagged spurdogs from the northern North Sea moved to Norway in winter and to Scotland in summer (FishBase).

Very varied: comb jellies, squid, mackerel and herring through many bottom fish, shrimp, crabs and even sea cucumbers (FishBase). Hunts in packs, formerly in schools of thousands (English Wikipedia, FishBase).

Size and age

FishBase: max. 200 cm (total length), common 100.0 cm, maximum published weight 9.1 kg, maximum age 75 years; in the North Atlantic usually 35 to 50 years, but most fish live only 20 to 24 years. German Wikipedia gives about 1 m and up to 10 kg, English Wikipedia age estimates of 35 to 54 years and individuals of nearly 70 years. The sources differ.

Protection and rules

Conservation status: IUCN: Vulnerable (assessed 2019; FishBase), in the northeast Atlantic Critically Endangered according to English Wikipedia, with stocks there down by at least 95% (English and German Wikipedia). Listed in Appendix II of the Bonn Convention (CMS; FishBase). The EU sets only commercial catch limits for spurdog (Regulation (EU) 2026/249, TAC tables 116 to 118), no specific rule for anglers; the German coastal regulations (Annex 1 KüFVO Schleswig-Holstein, § 4 KüFVO M-V, § 6 NKüFischO) do not list it. Checked on 21 Oct 2026. Pescaday recommends releasing every spurdog with care. Caution: the spines are venomous (FishBase).

We found no minimum size or closed season for this species in any state fisheries regulation. Local water rules may still apply.

Check the rules

In Germany, closed seasons and minimum sizes are set by each state and can be stricter for single waters. All German rules by state, with the legal source. Outside Germany, the local rules apply: licence and agency by country.

In the kitchen

Sold in Germany as "Seeaal" (back pieces) and "Schillerlocken" (smoked belly flaps), in Britain as "huss" (German and English Wikipedia). According to German Wikipedia the meat is usually heavily loaded with methylmercury: a 150 g portion of Schillerlocken exceeds the tolerable daily intake for adults tenfold, according to a study by Kiel University. Given its status and contamination, better released.

Sources (6)

Last checked 2026-10-22. Found a mistake? Write to [email protected].

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