Fisheries and Resources Monitoring System

Yellowtail flounder - Grand Bank
Fact Sheet Title  Fact Sheet
Stocks management recommendations 2021
Yellowtail flounder - Grand Bank
Fact Sheet Citation  
Yellowtail flounder in Div. 3LNO
Owned byNorthwest Atlantic Fisheries Organization (NAFO) – ownership
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Species List:
Species Ref: en - Yellowtail flounder, fr - Limande à queue jaune, es - Limanda, ru - Камбала желтохвостая (=лиманда желтохвостая)
ident Block Yellowtail flounder - Grand Bank
Aq Res
Biological Stock: Yes         Value: Regional
Management unit: Yes        Reference year: 2020
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 TrendVirgin-Large stock sizePre-exploitation biomass or high abundance

The stock biomass increased from 1994 to 2001, after which it remained stable until 2014. Biomass subsequently declined from ~2 times Bmsy and is currently 1.4 times Bmsy (Bmsy = 89 790 tons). There is very low risk of the stock being below Bmsy or F being above Fmsy. Recent recruitment appears to be higher than average.
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
Aq Res Struct
Biological Stock: Yes

Yellowtail flounder is caught in a directed trawl fishery and as by-catch in other trawl fisheries. The fishery is regulated by quota and minimum size restrictions. Catches in recent years have been low due to industry-related factors. American plaice and cod are taken as by-catch in the yellowtail fishery. There is a 15% by-catch restriction on American plaice and a 4% limit on cod.

Effects of the fishery on the ecosystem

Fishing intensity on yellowtail flounder has impacts on Div. 3NO cod and Div. 3LNO American plaice through by-catch. General impacts of fishing gears on the ecosystem should also be considered. Areas within Divs. 3LNO have been closed to protect sponge and coral.
Bio Assess
Ref Point

Blim is 30% Bmsy and Flim is Fmsy (STACFIS 2004 p. 133).

Medium-term projections were carried forward to the year 2025 with catch in 2021 assumed to be the TAC=17 000 t. Constant fishing mortality was applied from 2022-2025 at several levels of F (F=0, Fstatus quo, 2/3 Fmsy, 85% Fmsy and Fmsy).

Fmsy was estimated to be 0.21. Fishing at Fmsy would first lead to a considerable yield in 2022, but yields are then projected to decline in the medium term with catch at 2/3 Fmsy, 85% Fmsy and Fmsy. At the end of the projection period, the risk of biomass being below Blim is less than 1% in all cases.

For the Fstatus quo projections, probability that F > Flim=Fmsy in 2022-2025 was less than 0.04 in the medium term. At 2/3 Fmsy, the probability that F > Flim was between 0.08 and 0.11 in the medium term. Projected at the level of 85% Flim, the probability that F > Flim ranges between 0.27 and 0.30 and for Fmsy projections, this probability increased to 0.50. For biomass projections, in all scenarios for 2022-2025, the probability of biomass being below Blim was less than 0.01. The probability that biomass in 2025 is greater than B2021 is 0.48, 0.41, 0.32 and 0.26 for projections of Fstatus quo, 2/3 Fmsy, 85% Fmsy, and Fmsy respectively.
Assess Models
Analytical assessment

A Schaefer surplus production model in a Bayesian framework was used for the assessment of this stock. The results were comparable to the previous assessment. Input data comes from research surveys and the fishery. Next assessment: 2024.

Fishing Mortality



Human impact

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

Biological and environmental interactions

As stock size increased from the low level in the mid-90s, the stock expanded northward and continues to occupy this wider distribution. This expansion of the stock coincided with warmer temperatures.

Despite the increase in stock size observed since the mid-90s, the average length at which 50% of fish are mature has been lower for both males and females in the recent period. There also seems to have been a slight downward trend in weight at length since 1996. The cause of these changes is unknown.

The Grand Bank (3LNO) Ecosystem Production Unit (EPU) is currently experiencing low productivity conditions and biomass has declined across multiple trophic levels and stocks since 2014.

Sci Advice

Special comments

Management of yellowtail flounder should take into consideration impacts on other stocks. Bycatch in the yellowtail flounder fishery may be impeding recovery of Div. 3NO cod and American plaice in Div. 3LNO, which have both been below Blim for many years and are currently experiencing reduced productivity conditions. Measures to reduce bycatch of American plaice in the yellowtail flounder fishery in particular, which currently has a 15% limit, could reduce the impact of fishing on the recovery of that stock. Such measures could include maintaining or reducing the yellowtail flounder TAC, reducing the bycatch limit, or seasonal closures in areas of high bycatch, in order to protect stocks in the collapsed zone.
Management unit: Yes


Recommendation for 2022 to 2024

Scientific Council advises that fishing mortality up to 85% Fmsy , corresponding to catches of 22 100 t, 20 800 t, and 19 900 t in 2022 to 2024 respectively, have risk of no more than 30% of exceeding Flim, and are projected to maintain the stock above Bmsy.

No explicit management plan or management objectives are defined by the Commission. Convention General Principles are applied.

Stock definition for management purposes

The stock occurs in Divisions 3LNO, mainly concentrated on the southern Grand Bank and is recruited from the Southeast Shoal area nursery ground.
Northwest Atlantic Fisheries Organization (NAFO) Scientific Council Documents SCR Doc. 20/09, 20/04, 21/18, 21/19 and SCS Doc. 21/05, 21/06, 21/09, 21/13. Click to open
Northwest Atlantic Fisheries Organization (NAFO). 2021. Report of the Scientific Council Meeting, 27 May -11 June 2021. NAFO SCS Doc. 21/14Rev. 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
Northwest Atlantic Fisheries Organization (NAFO). 2004. NAFO Precautionary Approach Framework. Annual Meeting, September 2004. NAFO FC Doc. 04/18. Click to open
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