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West African croakers - Nigeria and Cameroon
Marine Resource  Fact Sheet
CECAF Scientific advice 2016
West African croakers - Nigeria and Cameroon
Fact Sheet Citation  
Grogneurs (Pseudotolithus spp) - Nigéria et Cameroun
Owned byFood and Agriculture Organization (FAO) – More
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Species:
Geographic extent of West African croakers - Nigeria and Cameroon
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Regional
Management unit: Yes        Reference year: 2010
 
 
Biological State and Trend
State & Trend Descriptors
PartnerFIRMS
Exploitation rateFcur/F0.1 = 69%; Fcur/FMSY = 62%Not applicable
Abundance levelBcur/B0.1 = 76% ; Bcur/BMSY = 84%Not applicable
FAO Categories
Exploitation stateFully exploited

Fcur/F0.1: Ratio between the observed fishing mortality coefficient during the last year of the series and F0.1.
Fcur/FSYcur: Ratio between the observed fishing mortality coefficient during the last year of the series and the coefficient that would give a sustainable yield at the current biomass level.
Fcur/FMSY: Ratio between the observed fishing mortality coefficient during the last year of the series and the coefficient that would give a maximum sustainable yield over the long term.
Bcur/B0.1: Ratio between the estimated biomass for the last year and the biomass corresponding to F0.1.
Bcur/BMSY: Ratio between the estimated biomass for the last year and the biomass corresponding to FMSY.
Unless otherwise indicated, the indicators were based on the Schaefer dynamic production stock assessment model.
Habitat and Biology
Climatic zone: Tropical.   Bottom type: Soft bottom clean sand; Soft bottom muddy or muddy-sand.   Depth zone: Coastal (0 m - 50 m).   Horizontal distribution: Littoral.   Vertical distribution: Demersal.  

Geographical Distribution
Jurisdictional distribution: Shared between nations

Water Area Overview
Spatial Scale: Regional

Geo References
Resource Structure
Considered a single stock: Yes
Exploitation
 
Fishery Indicators
TypeMeasureValueUnitTime period
ProductionCatch 19419tonnes1990
Catch 25625tonnes1991
Catch 22730tonnes1992
Catch 13644tonnes1993
Catch 14449tonnes1994
Catch 17781tonnes1995
Catch 18343tonnes1996
Catch 21272tonnes1997
Catch 18765tonnes1998
Catch 16957tonnes1999
Catch 17501tonnes2000
Catch 19005tonnes2001
Catch 13553tonnes2002
Catch 16687tonnes2003
Catch 16164tonnes2004
Catch 12369tonnes2005
Catch 14292tonnes2006
Catch 12935tonnes2007
Catch 14437tonnes2008
Catch 13427tonnes2009
Catch 8719tonnes2010
Assessment
 

Assessment year: 2011
The CECAF Working Groups have adopted the following Biological Reference Points (BRPs):
- Limit Reference points: BMSY and FMSY
- Target Reference Points: B0.1 and F0.1
Stock status is assigned based on current estimates of fishing mortality (Fcur) and biomass (Bcur) relative to these target and limit reference points (Bcur/BMSY, Fcur/FMSY, Bcur/B0.1, Fcur/F0.1). The results from the stock assessment of this stock are found under the “Biological state and trend section”.
Assessment Model
Type:  Biomass-aggregated
Schaefer dynamic production model

Assessment was carried out using Nigeria and Cameroon catch data and CPUE for Cameroon (Industrial trawlers). The catch data from Equatorial Guinea was not considered in this assessment because the time series data started in 2001 whereas Nigeria and Cameroon had consistent data from 1990 to 2010. Also, no assessment was done for the stock of Sao Tome & Principe because the unit effort was not in the appropriate format. The initial input data for the biodyn assessment were: r = 0.75; K=150 358 tonnes and BI/K = 60 percent.
Overall Assessment Results

The model gives an acceptable fit to the data of Nigeria, Cameroon, with CPUE of Cameroon industrial trawlers. The stock seems to be fully exploited. All the results should be treated with caution, because the data are not precise (or accurate or reliable).
Scientific Advice

Given the results obtained in the assessment of the stock of Nigeria and Cameroon and the trends in CPUE, the Working Group recommends a reduction in fishing effort. Total catch should not exceed the 2010 catch of 8 000 tonnes per year for the stock of Nigeria and Cameroon.
Management
Management unit: Yes
Source of information
 
FAO. 2016. Fishery Committee for the Eastern Central Atlantic, Report of the seventh session of the Scientific Sub-Committee, Tenerife, Spain, 14–16 October 2015 / Comité des pêches pour l’Atlantique Centre-Est Rapport de la septième session du Sous-Comité scientifique. Tenerife, Espagne 14-16 octobre 2015. FAO Fisheries and Aquaculture Report / FAO Rapport sur les pêches et l’aquaculture No. 1128. Rome, Italy.  Click to openhttp://www.fao.org/3/a-i5301b.pdf
FAO. 2015. Report of the FAO/CECAF Working Group on the Assessment of Demersal Resources – Subgroup South. Accra, Ghana, 15–24 November 2011 / Rapport du Groupe de travail FAO/COPACE sur l’évaluation des ressources démersales – Sous-groupe Sud. Accra, Ghana, 15-24 novembre 2011. CECAF/ECAF Series/COPACE/PACE Séries. No. 15/76. Rome, Italy/Italie.  Click to openhttp://www.fao.org/3/a-i5138b.pdf
Bibliography
 
All references to figures, tables and bibliography in the text are found within the source of information.
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