Fisheries and Resources Monitoring System

Thorny skate - Grand Bank
Fact Sheet Title  Fact Sheet
Stocks management recommendations 2022
Thorny skate - Grand Bank
Fact Sheet Citation  
Skates in Div. 3LNO
Owned byNorthwest Atlantic Fisheries Organization (NAFO) – ownership
ident Blockident Blockdisplay tree map
Species List:
Species Ref: en - Starry ray, fr - Raie radiée, es - Raya radiante, ar - شِفنين بحري شعاعية, zh - 辐鳐
ident Block Thorny skate - Grand Bank
Aq Res
Value: Regional        Management unit: Yes
Reference year: 2021
Aq Res State Trend
Aq Res State Trend
Aq Res State Trend Aq Res State Trend
Aq Res State TrendNone-Low Fishing MortalityNo or low fishing mortalityGreen
Aq Res State TrendIntermediate Stock SizeIntermediate abundance

The stock was above Blim in 2019. No new survey information is available to determine stock status. However, due to the longevity of the species and the stability of the catch in recent years, it is unlikely that there have been major changes to the state of the stock. Recruitment was average in 2019 and is currently unknown. Fishing mortality is currently unknown but thought to be low.
Habitat Bio
Climatic Zone: Temperate.   Bottom Type: Unspecified.   Depth Zone: Slope - Deepslope (500 m - 1000 m).   Horizontal Dist: Neritic.   Vertical Dist: Demersal/Benthic.  

Geo Dist
Geo Dist: Straddling between High Seas and EEZ

Water Area Overview
Spatial Scale: Regional

Water Area Overview

Thorny skate is caught in directed gillnet, trawl and long-line fisheries. In directed thorny skate fisheries, Atlantic cod, monkfish, American plaice and other species are landed as bycatch. In turn, thorny skate are also caught as bycatch in gillnet, trawl and long-line fisheries directing for other species. The fishery in NAFO division 3LNO is regulated by quota.

Recent catch estimates and TACs are:

Effects of the fishery on the ecosystem

The impact of bottom fishing activities on major VMEs in the NRA was last assessed in 2021. The risk of Significant Adverse Impacts (SAIs) on sponge and large gorgonian VMEs was assessed to be low, while this risk for sea pen VMEs has been assessed as intermediate. The risks of SAIs on small gorgonian, black coral, bryozoan and sea squirt VMEs were assessed as high. This assessment of impacts of bottom fishing activities on VMEs does not include waters within coastal states jurisdictions. Within the Grand Bank (3LNO) EPU areas in Div. 3O and 3L have been closed to fishing to protect corals.
Bio Assess
Ref Point

Blim defined from survey indices as Bloss (NAFO SCS 15/12).
Assess Models
Analytical assessment

Based upon a qualitative evaluation of stock biomass trends and recruitment indices. The assessment is considered data limited and, as such, associated with a relatively high uncertainty. Input data are research survey indices and fishery data. The next full assessment of this stock will be in 2024.



Fishing Mortality

Human impact

Mainly fishery related mortality has been documented. Mortality from other human sources (e.g. pollution, shipping, oil-industry) are undocumented.

Biological and environmental interactions

Thorny skate are found over a broad range of depths (down to 840 m) and bottom temperatures (-1.7 - 11.5ºC). Thorny skate feed on a wide variety of prey species, mostly on crustaceans and fish. Recent studies have found that polychaete worms and shrimp dominate the diet of thorny skates in Div. 3LNO, while hyperiids, snow crabs, sand lance, and euphausiids are also important prey items.

The Grand Bank (3LNO) EPU continues to experience low overall productivity conditions, and total biomass remains well below pre-collapse levels. However, recent warming, earlier phytoplankton spring bloom, and an increase in the proportion of energy-rich copepod species may have positive effects on total ecosystem production in the coming years.

Sci Advice

Special comments

The life history characteristics of thorny skate result in low rates of population growth and are thought to lead to low resilience to fishing mortality.
Management unit: Yes


Recommendation for 2023-2024

The stock has been stable at recent catch levels in Div. 3LNO (approximately 3 710 t, 2017 - 2021) however, given the low resilience to fishing mortality and higher historic stock levels, Scientific Council advises no increase in catches.

No explicit management plan or management objectives have been defined by the Commission. Convention General Principles are applied (NAFO GC Doc. 07-04). Advice is based on survey indices and catch trends in relation to estimates of recruitment.

Stock definition for management purposes

The management unit is confined to NAFO Div. 3LNO, which is a portion of the stock that is distributed in NAFO Div. 3LNO and Subdivision 3Ps.
Northwest Atlantic Fisheries Organization (NAFO) Scientific Council Documents SCR Doc. 14/23, 15/40, 22/26, 22/05, 22/14, 22/41 and SCS Doc. 15/12Rev, 20/06, 20/09, 20/10, 20/13. Click to open
Northwest Atlantic Fisheries Organization (NAFO). 2022. Report of the Scientific Council Meeting, 03 – 16 June, 2022. NAFO SCS Doc. 22/18. Click to open
Northwest Atlantic Fisheries Organization (NAFO). 2008. Resolution on the Interpretation and Implementation of the Convention on the Future Multilateral Cooperation in the Northwest Atlantic Fisheries. 30th Annual Meeting, September 2008. NAFO/GC Doc. 08/3. Click to open
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