Fisheries and Resources Monitoring System

American Plaice - Grand Bank
Fact Sheet Title  Fact Sheet
Stocks management recommendations 2021
American Plaice - Grand Bank
Fact Sheet Citation  
American plaice in Div. 3LNO
Owned byNorthwest Atlantic Fisheries Organization (NAFO) – ownership
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Species List:
Species Ref: en - Amer. plaice(=Long rough dab), fr - Balai(=Plie canadienne), es - Platija americana, ar - هوشع كندي, zh - 拟庸鲽, ru - Камбала-ерш
ident Block American Plaice - 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 mortalityRed
Aq Res State TrendDepleted Stock SizeDepleted

Fishing mortality increased from the late 1990s to 2015 and has subsequently declined. Recruitment has been very low in the last two decades. The stock remains low compared to historic levels and is presently considered to be below Blim.
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

The stock has been under moratorium since 1995. American plaice in recent years is caught as bycatch mainly in otter trawl fisheries of yellowtail flounder, skate and redfish.

Recent catch estimates and TACs are:

Effects of the fishery on the ecosystem

No specific information is available. There is no directed fishery for this stock. General impacts of fishing gears on the ecosystem should be considered. Areas within Divs. 3LNO have been closed to protect sponges and coral.
Bio Assess
Ref Point

Blim: 50 000 t of spawning biomass (Scientific Council Report, 2003)

Bmsy: 242 000 t of spawning biomass (Scientific Council Report 2011)

Flim: 0.31 (Scientific Council Report, 2011)

Due to model instability, projections were not completed for this stock. There is considered to be low potential for stock growth.
Assess Models
Analytical assessment

An analytical assessment using the ADAPTive framework tuned to the Canadian 3LNO spring, Canadian 3LNO autumn and the EU-Spain Div. 3NO survey is used for this stock. While results are considered by SC to indicative of stock trends, the absolute magnitude of population estimates from this model was not accepted by SC given a large retrospective pattern that consistently and significantly overestimates SSB and underestimates F. Several formulations of the ADAPT VPA with increases in the natural mortality assumption since at least 2005 were also considered. In addition, results of two independent populations models – a State-Space Model and a Spatial SURBA – were presented. Overall stock trends were consistent across models and support the conclusions of stock status from the base ADAPT.

The next full assessment is scheduled for 2024.

Fishing Mortality



The multiple lines shown in the graphs correspond to alternate models and model formulations considered by SC. The black line indicates the base run of the ADAPT VPA.

Human impact

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

Biological and environmental interactions

Capelin and sandlance as well as other fish and invertebrates are important prey items for American plaice. There has been a decrease in age at 50% maturity over time, possibly brought about by some interaction between fishing pressure and environmental/ecosystem changes during that period. The Grand Bank (3LNO) EPU is currently experiencing low productivity conditions and biomass has declined across multiple trophic levels and stocks since 2014.

Sci Advice

Special Comments

SC has identified a need to undertake a benchmark process to develop a new modelling framework for this stock.

From the early 2000s to around 2015, there was an increase in fishing mortality, and there is evidence of a concurrent increase in natural mortality. The combined impact of these factors is impeding recovery of this stock.

There is a tendency to overestimate SSB and underestimate F in the assessment model. In the current assessment there is a substantial downwards (47%) revision of the SSB in 2016, relative to the 2016 assessment.
Management unit: Yes


Recommendation for 2022 - 2024

Scientific Council recommends that, in accordance with the rebuilding plan, there should be no directed fishing on American plaice in Div. 3LNO in 2022, 2023 and 2024. Bycatch of American plaice should be kept to the lowest possible level and restricted to unavoidable bycatch in fisheries directing for other species.

In 2011 FC adopted an “Interim 3LNO American Plaice Conservation Plan and Rebuilding Strategy” (FC Doc. 11/21). There is a Harvest Control Rule (HCR) in place for this stock.

Stock definition for management purposes

The management unit is NAFO Divisions 3LNO. The stock is distributed throughout Div. 3LNO but historically most of the biomass was found in Div. 3L.
Northwest Atlantic Fisheries Organization (NAFO) Scientific Council Documents. SCS Doc. 18/05, 18/06, 18/07, 18/08, 18/13, 18/14, 18/15 and SCR Doc. 18/11, 18/17, 18/18, 18/19. 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). 2011. Interim 3LNO American Plaice Conservation Plan and Rebuilding Strategy. 33rd Annual Meeting – September 2011. NAFO/FC Doc. 11/21. Click to open
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