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Yellowtail flounder - Grand Bank
Marine Resource  Fact Sheet
Stocks management recommendations 2018
Yellowtail flounder - Grand Bank
Fact Sheet Citation  
Yellowtail flounder in Div. 3LNO
Owned byNorthwest Atlantic Fisheries Organization (NAFO) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Yellowtail flounder, fr - Limande à queue jaune, es - Limanda, ru - Камбала желтохвостая (=лиманда желтохвостая)
Geographic extent of Yellowtail flounder - Grand Bank
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Regional
Management unit: Yes        Reference year: 2017
 
 
Biological State and Trend
State & Trend Descriptors
PartnerFIRMS
Exploitation rateNone- Low Fishing MortalityNo or low fishing mortalityGreen
Abundance levelVirgin-Large stock sizePre-exploitation biomass or high abundance
Habitat and Biology
Climatic zone: Temperate.   Bottom type: Unspecified.   Depth zone: Slope - Deepslope (500 m - 1000 m).   Horizontal distribution: Neritic.   Vertical distribution: Demersal/Benthic.  

Geographical Distribution
Jurisdictional distribution: Straddling between High Seas and EEZ

Water Area Overview
Spatial Scale: Regional

Geo References
Resource Structure
Considered a single stock: Yes
Exploitation
 

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.

Recent catch estimates and TACs (‘000 t) are as follows:
  2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
TAC 17 17 17 17 17 17 17 17 17 17
STATLANT 21 5.5 9.1 5.2 3.1 10.7 8.0 6.7 8.3 9.2  
STACFIS 6.2 9.4 5.2 3.1 10.7 8.0 6.9 9.3 9.2  



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.
Assessment
 
Overall Assessment Results
Reference Point
 

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


  Yield (‘000t) P(F>Flim) P(B>Blim) P(B>Bmsy)  
  2019 2020 2021 2019 2020 2021 2019 2020 2021 2022 2019 2020 2021 2022 P(B2022>B2018)
Fstatus quo = 0.07 9.14 9.30 9.41 <1% <1% <1% <1% <1% <1% <1% 3% 3% 3% 2% 62%
2/3 FMSY = 0.14 19.52 18.41 17.77 6% 7% 8% <1% <1% <1% <1% 3% 5% 7% 10% 37%
85% FMSY = 0.18 24.88 22.49 21.09 25% 25% 27% <1% <1% <1% <1% 3% 7% 12% 18% 28%
FMSY = 0.21 29.28 25.50 23.37 50% 50% 50% <1% <1% <1% <1% 3% 9% 18% 27% 22%



Projections were conducted assuming catch in 2018 to be the average of that in 2013-2017, followed by constant fishing mortality from 2019-2021 at either Fstatus quo, 2/3 Fmsy, 85% Fmsy, and Fmsy. Fishing at Fmsy would first lead to a considerable yield in 2019, but yields are then projected to decline in the medium term with catch at 2/3 Fmsy, 85% Fmsy , and Fmsy. The risk of biomass being below Blim is less than 1% in all years for each scenario. The probability that biomass in 2022 is greater than B2018 is 0.62, 0.37, 0.28 and 0.22 for Fstatus quo, 2/3 Fmsy, 85% Fmsy, and Fmsy respectively.
Assessment Model
Analytical assessment
Results

A Bayesian surplus production model was used for the first time and results were comparable to the previous assessment. Input data comes from research surveys and the fishery.

The next assessment is planned for 2021.

Fishing Mortality

Recruitment

Biomass

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; temperatures continue to warm, and will likely not limit the stock distribution in the near future.

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) EPU is currently experiencing low productivity conditions and biomass has declined across multiple trophic levels and stocks since 2014.
Scientific Advice

Catch of yellowtail flounder has been below TAC in recent years. Management decisions on this stock should also take into consideration impacts on other fisheries. Increased catch of yellowtail flounder may increase by-catch of Div. 3NO cod and Div. 3LNO American plaice.
Management
Management unit: Yes

Management Advice

Recommendation for 2019, 2020 and 2021
Management Objectives

No explicit management plan or management objectives are defined by the Commission. General convention objectives (NAFO/GC Doc 08/3) are applied. Advice is provided in the context of the Precautionary Approach Framework (NAFO/FC 04/18).

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.
Source of information
 
SCR 11/34, 18/012, 18/017, 18/036, 18/038, 18/048; SCS 18/05, 18/06, 18/07, 18/08, 18/13, 18/14, 18/15; NAFO/GC Doc 08/3 NAFO/FC 04/18. Click to openhttps://www.nafo.int/Library/Science/SC-Documents
Report of the Meeting, 01 - 14 June, 2018 - SCS Doc. 18/19 Click to openhttps://www.nafo.int/Library/Science/SC-Documents
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