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Marine Resource Fact Sheet |
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West African croakers - Guinea-Bissau and Guinea |
Otoliths (Pseudotolithus spp) - Guinée-Bissau et Guinée |
| Data Ownership | This document provided, maintained and owned by Food and Agriculture Organization (FAO) , is part of CECAF Stock Status Reports data collection. |
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Related observations | Locate in inventory | | Species: | FAO Names: en - West African croakers nei, fr - Otolithes nca, es - Corvinas africanas nep, ru - Горбыли-капитаны |
Fishery IndicatorsProduction: Catch FAO Names: en - Longneck croaker, fr - Otolithe nanka, es - Corvina bosoro |
Fishery IndicatorsProduction: Catch FAO Names: en - Cassava croaker, fr - Otolithe sénégalais, es - Corvina casava |
Fishery IndicatorsProduction: Catch |
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| Geographic extent of West African croakers - Guinea-Bissau and Guinea
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FAO Fishing Statistical Division Areas |
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34.3.3 | Sherbro |
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FAO Fishing Statistical Subdivision Areas |
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34.3.13 | Atlantic, East central / 34.3.13 |
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Main Descriptors | Considered a single stock: Yes
Spatial Scale: Regional Management unit: Yes
Reference year: 2009
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Considered a single stock: A group of individuals in a species occupying a well defined spatial range independent of other stocks of the same species. It can be affected by random dispersal movements and directed migrations due to seasonal or reproductive activity. |
Spatial Scale: Spatial scale contains a standard term such as Global, Regional (e.g. for the whole Atlantic), sub-regional (e.g. for a part of the Atlantic), national, local (for sub-national levels). |
Considered a management unit: An aquatic resource or fishery is
declared as [Fishery] Management Unit if it is
effectively the focus for the application of selected
management methods and measures, within the broader
framework of a management system. According to the FAO
Glossary for Responsible Fishing, "a Fishery Management
Unit (FMU) is a fishery or a portion of a fishery
identified in a Fishery Management Plan (FMP) relevant
to the FMP's management objectives." FMU's may be
organised around fisheries biological, geographic,
economic, technical, social or ecological dimensions ,
and the makeup and attribute of a fishery management
unit depends mainly on the FMP's management
objectives. |
Jurisdictional distribution: Jurisdictional qualifier (e.g.
"shared", "shared - highly migratory") of the aquatic
resource related with its spatial distribution. |
Environmental group: Classification of the aquatic
resource according to the environmental group (e.g.
pelagic invertebrate, or demersal fish) to which the
species belong. |
Reference Year: The Reference Year is the last year considered in the stock assessment and/or fishery status. |
| | | | Biological State and Trend 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: Estuarine; Neritic. Vertical distribution: Demersal/Benthic. Geographical Distribution Jurisdictional distribution: Shared between nations Geo References  | Geographic extent of West African croakers - Guinea-Bissau and Guinea
FAO Fishing Statistical Division Areas | 34.3.3: Sherbro | FAO Fishing Statistical Subdivision Areas | 34.3.13: Atlantic, East central / 34.3.13 |
| | | | More Geo References
Exclusive Economic Zone Areas (EEZ) | GNB: Guinea-Bissau | GIN: Guinea |
| | | | Intersecting Major FAO areas and LME areas |
The following area codes have been found as intersecting the distribution of West African croakers - Guinea-Bissau and Guinea Resource Structure Considered a single stock: Yes The Working Group has considered a single stock of Pseudotolithus spp. for the assessment of Guinea- Bissau and Guinea. Exploitation Fishery Indicators Type | Measure | Value | Unit | Time period |
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Production | Catch | 6255 | tonnes | 1994 | Catch | 11100 | tonnes | 1995 | Catch | 12224 | tonnes | 1996 | Catch | 11467 | tonnes | 1997 | Catch | 10768 | tonnes | 1998 | Catch | 9972 | tonnes | 1999 | Catch | 12505 | tonnes | 2000 | Catch | 12666 | tonnes | 2001 | Catch | 11221 | tonnes | 2002 | Catch | 13491 | tonnes | 2003 | Catch | 15147 | tonnes | 2004 | Catch | 19312 | tonnes | 2005 | Catch | 11735 | tonnes | 2006 | Catch | 12246 | tonnes | 2007 | Catch | 7954 | tonnes | 2008 | Catch | 7005 | tonnes | 2009 |
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 The total catches of Pseudotolithus spp. for Guinea-Bissau and Guinea for the period 1995-2009 were used. The catches of Guinea-Bissau were estimated6 for the periods 1998-1999 and 2002-2004. Those of Guinea for the year 2009 were estimated assuming the exploitation was the same as in 2008. The abundance indices used were those from scientific surveys carried out in Guinea. The Working Group considered that these data better reflected the abundance of this group of species than the CPUE of other types of fleets of the two countries. The initial input parameters were r (intrinsic growth rate) = 2.30; K (initial biomass) = 20 000 and BI/K (biomass of the stock at the beginning of the data series, compared with the initial biomass) = 74 percent. Overall Assessment Results The model provides a satisfactory fit to the data. The overall result is that the stock is overexploited. However, the other information on the fishery shows that the Pseudotolithus spp. stock is fully exploited. Scientific Advice Reduction in the fishing effort compared with the 2009 level. The total catch should not exceed the 2009 catch (7 000 tonnes). 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. http://www.fao.org/3/I5301Bi/i5301bi.pdfFAO. 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. http://www.fao.org/3/a-i5138b.pdf |
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