Spurdog, Spiny Dogfish, Dogfish, Rock Salmon or Flake

Squalus acanthias

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — All Areas (Barents sea to Portuguese Coast)
Stock detail

1 to 9


Picture of Spurdog, Spiny Dogfish, Dogfish, Rock Salmon or Flake

Sustainability rating five info

Sustainability overview

Avoid buying Spurdog. Spurdog is a long-lived, slow-growing, and late-maturing species and therefore particularly vulnerable to fishing mortality. The North East Atlantic stock is critically endangered and listed by OSPAR as a threatened and/or declining species. Scientists recommend that no Spurdog should be landed in 2017 and 2018. Bycatch and discarding in non-target fisheries is still thought to be a problem and must be minimised to allow the stock to rebuild. Recent research has focused on designing a risk-based traffic light system to avoid their capture and a responsible handling code of conduct to increase survivability when discarded.

Biology

Spurdog (spiny dogfish, dogfish, rock salmon or flake) are sharks. In the North Atlantic female dogfish grow to a maximum total length of 110-124 cm, males 83-100 cm. In the Northwest Atlantic spurdog mature at around 60 cms total length and at an age of 6 years for males and at around 75 cms, at an age of 12 years for females. In the Northeast Atlantic females are reported to mature slightly larger and older at 83 cm 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 called ‘pups’. The fecundity of spurdog increases with length, and females of 100-120 cm produce a higher number of pups (10-21) than those females below this length. Spurdog forms size and sex-specific schools.

Stock information

Criterion score: 1 info

Stock Area

All Areas (Barents sea to Portuguese Coast)

Stock information

Spurdog populations appear to be well below healthy levels. Spurdog is a long-lived, slow-growing, and late-maturing species and is therefore particularly susceptible to fishing.

Scientists advice that there should be no targeted fisheries on this stock in 2017 and 2018, yet catches remain at around 2468 tonnes per year.

Until the 1990s, Spurdog was one of the most commonly recorded shark species in trawl surveys but their tendency to aggregate and their seasonal migrations, mean that it is difficult to properly assess their populations. They prefer cold waters and their populations seem to be decreasing with climate change. The species may also be retreating northwards to find cooler waters.

Since scientists advise that no landings should be taken, this rating is automatically red rated.

Management

Criterion score: 1 info

There is no management plan for this stock in this area. Management has only really been in place since 2009 and fishing rates have been reduced to safer levels. This has led to an increase in populations but it is difficult to measure species populations and their recovery rate is slow. To help the species recover, scientists recommend that no target fishing should take place but discarding still occurs.

Scientists recommend that this species should be managed by a minimum landing length (MLL) of 100cm. Norway has implemented a MLL of 70cm since 1964. Recent research has been conducted to improve Spurdog management in UK waters: this includes allowing a small (2 tonnes) bycatch allowance for scientific research. A selectivity grid was identified as a potential, viable gear modification to reduce Spurdog bycatch in towed commercial fishing gear. A code of conduct and selectivity trials have been trialled in some areas.

Spurdog survival varies largely depending on how it is caught and handled. However, the way these species are managed by change with the implementation of the landings obligation in 2019.

There are a mixture of data collected for the stock such as trawl surveys and landings data are collected.

Capture Information

Criterion score: 1 info

Historically, Spurdogs were taken in large target fisheries but are now caught as bycatch in mixed demersal trawl fisheries.

Bycatch
Catching large numbers of Spurdog in nets can negatively impact the survival of the other species in that net. Spurdog damage other species because their skin is extremely rough and they have spines on their skin. When caught in longline fisheries, Spurdog survival rates are higher.

Fishermen often try to reduce the capture of Spurdog: trials to reduce Spurdog fishing mortality have tested using a real-time, self-reporting Spurdog by-catch avoidance scheme and electric pingers to trawling gear, to deter Spurdogs. The Shark Trust have designed a code of conduct to encourage responsible handling of Spurdog to improve their survival rates upon discarding.

Habitat
Bottom trawling has the potential to cause significant impact to habitat such as removing or destroying physical features and reducing biota and habitat complexity. Therefore, the recovery time of the seabed after trawling varies greatly and depends on the fishing gear, the substrate, intensity of the trawl and accustomed the seabed is to natural disturbance. Fishing occurs over a mixture of seafloor types. IFCAs ensure bottom trawling occurs in areas where there will be minimal damage to habitats such as mobile sands, however, in offshore areas, bottom trawling can occur over vulnerable habitats.

Alternatives

Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.

Basa, Tra, Catfish or Vietnamese River Cobbler
Bass, seabass (Farmed)
Bream, Gilthead (Farmed)
Cod, Atlantic Cod
Cod, Pacific Cod
Coley, Saithe
Haddock
Hake, Cape
Hake, European
Pollock, Alaska, Walleye
Sturgeon (Farmed)
Tilapia
Whiting

References

Hunter, E, Hetherington, S., Ross, E.J., Scutt Phillips, J., Phillips, Nicholson, R., Borrow, K., Rutland, L.E., Donnan, D., Wiggins, J., Righton, D. & Bendall, V. 2016. Shark By-Watch UK 2 - Understanding by-catch of elasmobranchs in UK waters: A nationwide programme, a regional approach.;

Shark Trust; 2010. An Illustrated Compendium of Sharks, Skates, Rays and Chimaera.: Spiny dogfish. Available at: http://www.sharktrust.org/en/rock_salmon;
http://www.sharktrust.org/shared/downloads/factsheets/spiny_dogfish_st_factsheet.pdf;
Fordham, S., Fowler, S.L., Coelho, R., Goldman, K.J. & Francis, M. 2006. Squalus acanthias (Northeast Atlantic subpopulation). The IUCN Red List of Threatened Species 2006: e.T44168A10866677. http://dx.doi.org/10.2305/IUCN.UK.2006.RLTS.T44168A10866677.en

Marine Management Organisation. 2017. Spurdog (picked dogfish) by-catch avoidance programme. Available at: https://www.gov.uk/government/news/spurdog-picked-dogfish-by-catch-avoidance-programme

Sguotti, C., Lynam, C. P., Garcia-Carreras, B., Ellis, J. R. and Engelhard, G. H. 2016. Distribution of skates and sharks in the North Sea: 112 years of change. Glob Change Biol, 22: 2729-2743. doi:10.1111/gcb.13316

ICES 2017a

ICES. 2016. Spurdog (Squalus acanthias) in the Northeast Atlantic. Available at: http://ices.dk/sites/pub/Publication%20Reports/Advice/2016/2016/dgs-nea.pdf

Sguotti, C., Lynam, C. P., Garcia-Carreras, B., Ellis, J. R. and Engelhard, G. H. 2016. Distribution of skates and sharks in the North Sea: 112 years of change. Glob Change Biol, 22: 2729-2743. doi:10.1111/gcb.13316

ICES. 2017a. Report of the Workshop to compile and refine catch and landings of elasmobranchs (WKSHARK3), 20-24 February 2017, Nantes, France . ICES CM 2017/ACOM:38. 119 pp.