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Spurdog by Marc Dando


Also known as spiny dogfish, rock salmon or flake, the spurdog is a small grey shark with spines at the base of each dorsal fin. They grow to a maximum size of 124 cm.

Sustainability Overview

Spurdog is a long-lived, slow-growing, and late-maturing species and therefore particularly vulnerable to fishing mortality, however thanks to a ban on fishing for this species for many years the population across the whole North East Atlantic has recovered and the latest ICES advice shows that this fishery can re open. Management needs to be tested to ensure that this species is not overfished again and we will be closely watching the situation and reviewing ratings where needed. 

 76 tonnes of spurdog were landed to Cornish ports legally in 2020, with a value of £131k (MMO data).

Updated April 2023

Sustainability ratings for this species

Demersal Trawl

Cornish waters (7e, 7f, 7g, 7h)

A large trawl held open by paravane trawl doors, the open net is then pulled along in contact with the seabed.

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Gill Netting

Cornish waters (7e, 7f, 7g, 7h)

Caught using monofilament nets set on the seabed.

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Beam Trawling

Cornish waters (7e, 7f, 7g, 7h)

Caught using heavy beam trawl nets that are dragged over the seabed.

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How we rate fish

Cornwall Good Seafood Guide rates fish on sustainability using a scale of 1 to 5.

1, 2 and 3 are recommended, Fish to avoid are rated 5.

We use the system devised by the Marine Conservation Society (MCS) so our scores are comparable with the scores produced by MCS for the UK and fisheries from all around the world. For more information on scoring click here.


Spurdogs are a highly migratory species that is capable of moving great distances in very little time. They grow slowly and have a low rate of reproduction meaning that this species is very vulnerable to fishing. Biological vulnerability rating is high 69%, Cheung et al 2005. Spurdog (spiny dogfish, dogfish, rock salmon or flake) are sharks. In the North Atlantic female dogfish grow to a maximum total length of 110-124cm, males 83-100cm. In the Northwest Atlantic spurdog mature at around 60cms total length and at an age of 6 years for males and at around 75cms, at an age of 12 years for females. In the Northeast Atlantic females are reported to mature slightly larger and older at 83cm total length and 15 years. Gestation or pregnancy lasts between 18 and 22 months, one of the longest recorded for any vertebrate, and they give birth to live young. The fecundity of spurdog increases with length, and females of 100-120cm produce a higher number of pups (10-21) than those females below this length. Spurdog tend to aggregate in groups of one sex and size.

Stock Info

This stock was benchmarked in 2021 with a substantial improvement in data available for the assessment. Results from the current model confirm that spurdog abundance declined due to high exploitation levels in the past, coupled with biological characteristics that make spurdog particularly vulnerable to such intense exploitation. This model also confirms that the stock is recovering from a low in the early- to mid-2000s, and is now above MSY Btrigger (336,796 tonnes). Biomass in 2022 was 540,266 tonnes. The current stock is thought to be around 45% of virgin biomass.
Fishing pressure on the stock has declined substantially since the early 2000s. The harvest rate (ages 5-30) is currently well below HR MSY (0.043). In 2021 it was 0.0031. 
ICES advises that when the MSY approach is applies, catches in 2023 and 2024 should be no more than 17,353 and 17,855 tonnes respectively. This is a significant change from the advice for 2021 and 2022 which was for zero catch. This change is due to the recent benchmark which led to a change in the perception of the stock and reference points.


This fishery has only recently reopened. The TAC has been set in line with advice but it is too soon to know if management measures will be effective in managing the stock.
From 2011-2023, there has been a zero Total Allowable Catch (TAC) in place for spurdog and it was on prohibited lists of both the EU and UK. In July 2016, an amendment to EU quota regulation allowed for a bycatch quota of 270 tonnes for those countries taking part in a pilot spurdog avoidance programme. During 2018, 2019, 2020, and 2021, the UK reported landings of 37, 52, 79, and 151 tonnes, respectively. For the UK, this was a major increase from a level close to zero that has been seen since the zero TAC was introduced in 2011.
In 2022, a change in perception of the stock and reference points led to ICES recommending a catch of 17,353 tonnes in 2023. Subsequently, three TAC units have been proposed for spurdog in the Northeast Atlantic:
  • North Sea (3,434 tonnes)
  • Western (10,899 tonnes)
  • Skagerrak (1,130 tonnes)
The UK will have an 81% share in the North Sea unit and a 44.31% share in the Western unit. The prohibition on landing spurdog in EU waters was lifted in January 2023, and in the UK, was lifted on 1st April 2023.
As a precautionary measure to protect mature and breeding females, all spurdog over 100cm must be discarded. Specimens 100cm or less must be landed under the Landing Obligation. It is not yet known how well this size limit will be enforced. Estimates of post-release mortality range from 6% to 29%.
This is a newly reopened fishery and it is too soon to know if management measures in place will be effective. We would like to see fisheries management plans in place for all UK fisheries, including spurdog.
In the UK, it is too early to tell how effective management is, as the Fisheries Act only came into force in January 2021. The Act requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans) but there are no details yet on how and when these will be developed. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. MCS is keen to see FMPs for all commercially exploited stocks, especially where stocks are depleted, that include:
Targets for fishing pressure and biomass, and additional management when those targets are not being met
Timeframes for stock recovery
Technologies such as Remote Electronic Monitoring (REM) to support data collection and improve transparency and accountability
Consideration of wider environmental impacts of the fishery

Capture Info

Spurdogs have been targeted in the past using nets and longlines but are now caught accidentally in gill nets, trawls and with longlines.   In 2019, 50 tonnnes of spurdog were landed to Cornish ports (MMO) data. Fishers say that it is very frustrating when they accidentally catch spurdogs as they damage gear and very large quantities are caught. It is reportedly very hard to avoid catching them despite sharing infomation with other skippers as the movement of schools is random. 


ICES advice 2022 Spurdogs 
IUCN Red list Spiny dogfish 2020
ICES advice 2020 Spurdogs
Project Neptune final Report CEFAS 2016
ICES advice October 2018 Spurdogs 
Spurdog by-catch avoidance Programme 
MMO landings data
Shark Trust; 2010. An Illustrated Compendium of Sharks, Skates, Rays and Chimaera. Chapter 1: The British Isles and Northeast Atlantic. Part 2: Sharks. 
OSPAR Commission 2010, Background information for spurdog or spiny dogfish, biodiversity series 2010
MB0125: Common Fisheries Policy reform implementation: aligning zero quota species and improving fisheries management – a spurdog case study. DEFRA
Fordham, S., Fowler, S.L., Coelho, R., Goldman, K.J. & Francis, M. 2006. Squalus acanthias. The IUCN Red List of Threatened Species. Version 2014.3. <>. Downloaded on 28 January 2015.

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