Aq Res State 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 Bio
Climatic Zone: Tropical. Depth Zone: Coastal (0 m - 50 m). Vertical Dist: Demersal.
Geo Dist
Geo Dist: Shared between nations
Aq Res Struct
Biological Stock: Yes
The Working Group considered one stock of Arius spp. for both countries.
Bio Assess
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”.
Assess Models
Type: Biomass-aggregated
Schaefer dynamic production model
The initial input parameters were, r (intrinsic growth rate) = 1.00; K (initial biomass) = 25 000 and BI/K (biomass of the stock at the beginning of the series of data, compared with the initial biomass) = 80 percent.
Results
The model provides a reasonably good fit to the data with modification of the environmental value 1 in 2000. The model follows the trends in the Guinean and Guinea-Bissau fisheries. The results show that the stock is not fully exploited. As the species has a coastal distribution an effort should be made to analyze this type of effort, by exploiting other species. The trawlers from Guinea probably do not reflect the stock abundance.
Sci Advice
As a precautionary measure, s not to increase fishing effort as a series of more complete and better quality data are not available. The catch should not exceed the 2009 level.
Sources
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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