Fisheries and Resources Monitoring System

Bonga shad - Guinea-Bissau, Guinea, Sierra Leone and Liberia
Marine Resource  Fact Sheet
CECAF Scientific advice 2016
Bonga shad - Guinea-Bissau, Guinea, Sierra Leone and Liberia
Fact Sheet Citation  
Ethmalose (Ethmalosa fimbriata) - stock nord (Guinée-Bissau, Guinée, Sierra Leone et Libéria)
Owned byFood and Agriculture Organization (FAO) – More
Monitoring periodPreviously monitored as: Bonga shad - Southern Area of Eastern Central Atlantic
Related observationsLocate in inventorydisplay tree map
FAO Names: en - Bonga shad, fr - Ethmalose d'Afrique, es - Sábalo africano, ru - Бонга

Fishery Indicators
Production: Catch
Geographic extent of Bonga shad - Guinea-Bissau, Guinea, Sierra Leone and Liberia
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Regional
Management unit: Yes        Reference year: 2012
Biological State and Trend
State & Trend Descriptors
Exploitation rateFcur/F0.1 = 110% ; Fcur/FMSY = 99%Not applicable
Abundance levelBcur/B0.1 = 111%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/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.
Unless otherwise indicated, the indicators were based on the Schaefer dynamic production stock assessment model.
Habitat and Biology
Climatic zone: Tropical.   Depth zone: Coastal (0 m - 50 m).   Vertical distribution: Pelagic.  

Geographical Distribution
Jurisdictional distribution: Shared between nations

Water Area Overview
Spatial Scale: Regional

Geo References
Resource Structure
Considered a single stock: Yes
Fishery Indicators
TypeMeasureValueUnitTime period
ProductionCatch 2tonnes1990
Catch 70tonnes1991
Catch 2tonnes1992
Catch 4tonnes1993
Catch 0tonnes1994
Catch 45290tonnes1995
Catch 47807tonnes1996
Catch 51344tonnes1997
Catch 49693tonnes1998
Catch 39403tonnes1999
Catch 50667tonnes2000
Catch 63262tonnes2001
Catch 68060tonnes2002
Catch 81448tonnes2003
Catch 83536tonnes2004
Catch 64034tonnes2005
Catch 86004tonnes2006
Catch 80679tonnes2007
Catch 114446tonnes2008
Catch 48348tonnes2009
Catch 39401tonnes2010
Catch 46585tonnes2011
Catch 59657tonnes2012

Assessment year: 2014
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

The model requires complete time series of data in total catch as well as an index of stock abundance. The estimates of total catch were obtained by adding the catch estimates of all the fleets in each country, and these were used as total catch series. The CPUE from Guinea’s artisanal fishery (1995-2012) was chosen, because for the series made available to the Working Group, it was believed to better reflect the variations of the biomass of the stock. The CPUE for 2005 was not considered in the assessment owing to an error in the estimates. For bonga, the artisanal CPUE was considered more appropriate than the industrial series. After an analysis of the time series, the Working Group decided to proceed with an assessment using the catch data from Guinea only given the lack of catch information from fisheries exploiting the stock from the other countries. For example, there is no information on artisanal catches in Guinea-Bissau and Liberia and no updated information from Sierra Leone for the recent years. The initial parameters used for the assessment model were: - Ethmalosa fimbriata: r =0.7, K = 150 000 tonnes and BI/K = 60 percent.
Overall Assessment Results

The model fit was considered satisfactory.
Scientific Advice

As a precautionary measure, do not increase catches from the average of the 5 last years (44 000 tonnes).
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 open
FAO. 2015. Report of the FAO/CECAF Working Group on the Assessment of Small Pelagic Fish – Subgroup South. Pointe Noire, Congo, 17–23 March 2014. Rapport du Groupe de travail FAO/COPACE sur l’évaluation des petits poissons pélagiques – Sous-groupe Sud. Pointe Noire, Congo, 17-23 mars 2014. CECAF/ECAF Series / COPACE/PACE Séries No. 15/75 Rome, FAO. 157 pp.  Click to open
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