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Bonga shad - Mauritania, Senegal and Gambia
Marine Resource  Fact Sheet
CECAF Scientific advice 2016
Bonga shad - Mauritania, Senegal and Gambia
Fact Sheet Citation  
Ethmalose (Ethmalosa fimbriata) - Mauritanie, Sénégal et Gambie
Owned byFood and Agriculture Organization (FAO) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Bonga shad, fr - Ethmalose d'Afrique, es - Sábalo africano, ru - Бонга

Fishery Indicators
Production: Catch
Geographic extent of Bonga shad - Mauritania, Senegal and Gambia
Main Descriptors
Considered a single stock: Yes        Spatial Scale: Regional
Management unit: Yes        Reference year: 2014
 
 
Biological State and Trend
State & Trend Descriptors
PartnerFIRMS
Exploitation rateFcur/F0.1 = 164%Not applicable
Abundance levelUncertain/Not assessedNot applicable
FAO Categories
Exploitation stateOverexploited

Fcur/F0.1: Ratio between the observed fishing mortality coefficient during the last year of the series and 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); Shelf (50 m - 200 m).   Horizontal distribution: Neritic.   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


The assumption that the West African bonga shad stock is a single stock was maintained by the Working Group. A detailed description of the stock is given in the 2007 report of the FAO Working Group. According to the synoptic presentation of biological data on the bonga shad by E. Charles Dominique (1982), the bonga shad (Ethmalosa fimbriata) is mainly concentrated in Mauritania, Senegal and The Gambia.
Exploitation
 
Fishery Indicators
TypeMeasureValueUnitTime period
ProductionCatch 22824tonnes1990
Catch 29188tonnes1991
Catch 24183tonnes1992
Catch 31385tonnes1993
Catch 30451tonnes1994
Catch 29635tonnes1995
Catch 40159tonnes1996
Catch 38066tonnes1997
Catch 35970tonnes1998
Catch 36816tonnes1999
Catch 39761tonnes2000
Catch 49365tonnes2001
Catch 43428tonnes2002
Catch 43511tonnes2003
Catch 27524tonnes2004
Catch 33157tonnes2005
Catch 23407tonnes2006
Catch 25383tonnes2007
Catch 23716tonnes2008
Catch 51763tonnes2009
Catch 61617tonnes2010
Catch 43131tonnes2011
Catch 62359tonnes2012
Catch 114941tonnes2013
Catch 83397tonnes2014
Assessment
 

Assessment year: 2015
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:  Size-structured
Length Cohort Analysis (LCA)

A length frequency average based on the total catch in the areas concerned was used. The lengths of the individuals of the final matrix derived are between 5 and 43 cm. The length frequencies in The Gambia for 2014 were not available to the Working Group, so the length frequencies from the southern part of Senegal was used to raise to the total catch of The Gambia. The growth and mortality parameters used (Table 7.6.1 of FAO, 2016b) in the two models were estimated by the Working Group based on the analysis of the modal progression using the FISAT II - Version 1.2.2 software (FAO-ICLARM Stock Assessment Tools) (Gayanilo, Sparre and Pauly, 2005). The parameters of the length-weight ratio used are derived from the FishBase data base.
Yield per Recruit Analysis (Y/R)

The results of the LCA were then used as input data for the yield-per-recruit model.
Overall Assessment Results

The results of the two methods showed that the fishing pressure on the bonga stock is very high and that the stock in sub-region is still overexploited. However, the results obtained from the analyses should be treated with caution in view of the uncertainties about selectivity and the lack of information for formulating assumptions on the identity of the bonga stock in the sub-region and its geographic distribution as well as the lack of biological data on the different fisheries.
Scientific Advice

The Working Group notes a general increasing trend in catches even though a decrease was observed in 2014. The Working Group recommends that effort should be decreased as compared to current levels for bonga to regain a catch level that can ensure sustainability.
Management
Management unit: Yes
Source of information
 
FAO. 2016a. 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. 2016b. Report of the FAO Working Group on the Assessment of Small Pelagic Fish off Northwest Africa. Casablanca, Morocco, 20–25 July 2015 / Rapport du Groupe de travail de la FAO sur l’évaluation des petits pélagiques au large de l’Afrique nord-occidentale. Casablanca, Maroc, 20-25 juillet 2015. FAO Fisheries and Aquaculture Report/FAO Rapport sur les pêches et l’aquaculture No. 1122. Rome, Italy/Italie.  Click to openhttp://www.fao.org/3/a-i5511bb.pdf
Bibliography
 
All references to figures, tables and bibliography in the text are found within the source of information.
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