Dogfish, Lesser Spotted

Scyliorhinus canicula

Method of production — Caught at sea
Capture method — Beam trawl
Capture area — North East Atlantic (FAO 27)
Stock area — North Sea, Skagerrak and Kattegat, eastern English Channel, West of Scotland, Irish Sea and southern Celtic Seas
Stock detail — 3a, 4, 7d
Picture of Dogfish, Lesser Spotted

Sustainability rating four info

Sustainability overview

Lesser spotted dogfish populations have been increasing over time with a slight decrease in the past year. There is a lack of monitoring and management to ensure that their population is at healthy levels. Beam trawling is also associated with discarding of unwanted fish and sometimes catch Endangered, Threatened and Protected and without adequate management, this fishing method can pose significant damage to the seafloor.

Biology

Lesser spotted dogfish or catshark belongs to one of the largest families of sharks, the dogfishes or Scyliorhinidae. Most commonly encountered around the coasts of northern Europe it is a bottom dwelling shark most usually found over sand, mud, algae, and rocky bottoms in coastal waters down to depths of 400 m. Like many elasmobranchs, the catshark often aggregates by size and sex.

In the North East Atlantic females reach first maturity at around 52 cm, with 50% of individuals mature by 57 cm (8 years) and all are expected to be mature by 69 cm. Males reach first maturity at around 49 cm, with 50% of individuals mature by 53.5 cm (6 to 7 years) and all mature 62 cm. Females lay their eggs during spring and early summer. The shark embryos are enclosed in cases (called ‘mermaids’ purses) whilst they develop and mature, a period of 5-11 months depending on sea temperature.

Catsharks can grow up to 1 metre in length, but rarely seen larger than 80 cm. Maximum age is reported as 12 years. They are also marketed as dogfish.

Stock information

Criterion score: 0.5 info

Stock Area

North Sea, Skagerrak and Kattegat, eastern English Channel, West of Scotland, Irish Sea and southern Celtic Seas

Stock information

Catshark (dogfish or lesser spotted dogfish) is common and widespread all around the coasts of Britain and Ireland. It is likely the most frequently caught elasmobranch in European waters. Lesser spotted dogfish reproduce relatively quickly compared to other sharks.

Their populations were steadily increasing until 2013 and their populations have been fluctuating since with declines. It is unknown if fishing levels are appropriate for the species.

Scientists advise that landings should be no more than 3380 tonnes in 2018 and 2019 each (2016 landings were estimated to be just under 3000 tonnes). In recent years, catch rates of S. canicula have been increasing in almost all surveys. There is no concern for biomass.

Discarding rates are known to be very high. Many dogfish survive discarding but it is unknown to what level.

Historical records show that lesser-spotted dogfish was previously far more abundant in the southern North Sea. The species has strongly increased in its populations since the 1970s and 1980s. Their populations have increased because of warming waters, new habitats and reduced competition with skate species (many dogfish feed upon other discarded species from trawl fisheries). There is no concern for fishing mortality.

Management

Criterion score: 0.75 info

There is no specific management plan or precautionary management plan for lesser spotted dogfish. There is no quota available and therefore, they will not be covered under the landing obligation. Their relatively high productivity, combined with their low commercial importance, makes them a low priority for proactive management. However, some Inshore Fishery Conservation Authorities (IFCAs) have implemented management measures e.g. minimum mesh sizes in fixed nets.

Monitoring
There are a lack of data for the species as they were not always recorded in landings data (as they are often used for bait, particularly in pot fisheries). When Lesser spotted dogfish catches are reported, they are often entered as generic categories as dog fish and hounds. Therefore, landings data are considered inaccurate.

There are a lack of data available for the species, though some fishery-independent surveys have been conducted.

The species is discarded in high numbers, and likely has high survival rates, though true fishing mortality is unknown because there is insufficient information to determine how many are used as bait or discarded (ICES 2017).

Capture Information

Criterion score: 0.75 info

In France, lesser spotted dogfish are landed as bycatch. Lesser spotted dogfish are mostly caught in bottom trawls. There is a higher retention rate of dogfish in otter trawls. There is a lack of information available on other bycatch species but in the southern North Sea, common bycatch in bottom trawls include mixed crabs, urchins, lesser spotted dogfish, nursehound, dragonet, starry ray, smelt. Endangered, Threatened and Protected (ETP) species are occasionally caught (Angelshark and Common skate (both critically endangered (IUCN)). Invertebrates such as crabs and urchins are vulnerable to damage.

Discards
Trawling is also associated with discarding of unwanted fish, i.e. undersized and/or non-quota and/or over-quota species but their capture rates can be reduced for example by inserting a square-mesh panel into the net. Since dogfish have very rough skin, they can harm other species caught in trawl nets and therefore reduce their potential survival rates if discarded. Projects are on-going to try and allow shark species to escape from trawls e.g. by having square-mesh panels and LED lights to help by-caught sharks escape nets. Lesser spotted dogfish are often discarded: where the discarding rate (defined by discards/landings) has been estimated at 170%. The species have been shown to have a high discard survival rate in beam and otter trawl fisheries (Revill et al., 2005; Rodriguez-Cabello et al., 2005), and anecdotal observations suggest that it would also have high survival in coastal longline fisheries.

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 how accustomed the seabed is to natural disturbance.

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
Coley, Saithe
Haddock
Hake, Cape
Hake, European
Monkfish, Anglerfish
Pollock, Alaska, Walleye
Sturgeon (Farmed)
Tilapia

References

Shark Trust 2010. An illustrated Compendium of Sharks, Skates, Rays and Chimaera. Chapter 1: The British Isles and Northeast Atlantic. Part 2: Sharks www.sharktrust.org

ICES 2017d. Lesser-spotted dogfish (Scyliorhinus canicula) in Subarea 4 and in divisions 3.a and 7.d (North Sea, Skagerrak and Kattegat, eastern English Channel). Version 2: 24 October 2017 DOI: 10.17895/ices.pub.3190. Available at: http://ices.dk/sites/pub/Publication%20Reports/Advice/2017/2017/syc.27.3a47d.pdfdf

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.

ICES. 2017. Report of the Working Group on Elasmobranchs (2017), 31 May-7 June 2017, Lisbon, Portugal. ICES CM 2017/ACOM:16. 1018 pp.