Biological State and Trend
Habitat and Biology
Climatic zone: Tropical. Depth zone: Coastal (0 m - 50 m); Shelf - Uppershelf (up to 100 m). Vertical distribution: Demersal.
Geographical Distribution
Jurisdictional distribution: National
Resource Structure
Considered a single stock: Yes
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
Total catches from all fleets operating from 1990 to 2010 were used by the Working Group for the assessment. The CPUE series from the Spanish fleet was taken as the index of abundance as it was considered that this series best reflects the trends in abundance of the stock. Missing CPUE values for 1999 were estimated from the period 1996-1998 assuming the exploitation pattern was the same in the period considered for the assessment. The initial parameter values for the Biodyn model are: r = 1.00; K = 16 000 tonnes; BI/K = 60 percent.
Overall Assessment Results
The model did not fit well with the estimates and observed CPUE data for the Sepia spp. stock, and no diagnosis can then be made from the results of the model that shows inconsistencies. Finally, the lack of information from the important fleets (Chinese and others) in 2009 and 2010 could influence the results, so the Working Group rejected this assessment.
Scientific Advice
As a precautionary measure, the catch should not exceed the level of the average 2007-2009 period (1 900 tonnes)
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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