Habitat Bio
Climatic Zone: Tropical. Bottom Type: Soft bottom clean sand; Soft bottom muddy or muddy-sand. Depth Zone: Coastal (0 m - 50 m); Shelf (50 m - 200 m). Vertical Dist: Demersal.
Geo Dist
Geo Dist: Shared between nations
Aq Res Struct
Biological Stock: Yes
The Working Group adopted one stock/unit for Nigeria and Cameroon for assessment purpose as they have data series from 1995 to 2016. Equatorial Guinea also provided data from 2002 to 2016 but the data sets from 2011 to 2016 were very low compared to previous data provided.
Exploit
CATCH: Table 4.5.3a and Figure 4.5.3a present the catches of soles in Cameroon, Nigeria and Equatorial Guinea. The trends are stable over the years for Cameroon and for Nigeria the catches increased steadily with some slight fluctuations up to 2015 and deceased slightly to 2016. Equatorial Guinean catch trends started in 2002 with a very sharp increase in 2003 and gradually decreases to 2011 this further reduced to 2016.
FISHING EFFORT: The fishing effort is the same for all demersal species. Trends in effort of these fleets are described in Section 4.3.3.
CPUE: CPUE shows fluctuations with a tendency to decrease for Cameroon and Equatorial Guinea but that of Nigeria increases in similar pattern as the catch over the years (Table 4.5.3b and Figure 4.5.3b).
Fishery Indicators
Type | Measure | Value | Unit | Time period |
---|
Production | Catch | 490 | tonnes | 1990 |
Catch | 551 | tonnes | 1991 |
Catch | 726 | tonnes | 1992 |
Catch | 912 | tonnes | 1993 |
Catch | 561 | tonnes | 1994 |
Catch | 2799 | tonnes | 1995 |
Catch | 1789 | tonnes | 1996 |
Catch | 1686 | tonnes | 1997 |
Catch | 2279 | tonnes | 1998 |
Catch | 4599 | tonnes | 1999 |
Catch | 7292 | tonnes | 2000 |
Catch | 7234 | tonnes | 2001 |
Catch | 980 | tonnes | 2002 |
Catch | 8315 | tonnes | 2003 |
Catch | 6816 | tonnes | 2004 |
Catch | 9379 | tonnes | 2005 |
Catch | 8524 | tonnes | 2006 |
Catch | 7873 | tonnes | 2007 |
Catch | 8308 | tonnes | 2008 |
Catch | 6716 | tonnes | 2009 |
Catch | 9005 | tonnes | 2010 |
Catch | 11779 | tonnes | 2011 |
Catch | 9826 | tonnes | 2012 |
Catch | 11856 | tonnes | 2013 |
Catch | 13325 | tonnes | 2014 |
Catch | 13176 | tonnes | 2015 |
Catch | 11802 | tonnes | 2016 |
Bio Assess
Assessment year: 2017
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”.
Data
To apply the assessment model the Working Group input the total catch of
Cynoglossus spp. for Nigeria and Cameroon during the period 2002 to 2016. The abundance indices used are the series of CPUE of industrial trawlers (kg/fishing day) from Cameroon.
Assess Models
Type: Biomass-aggregated
Schaefer dynamic production model
The Schaefer dynamic production model implemented in an Excel spreadsheet was used by the Working Group to assess the state of the Cynoglossus spp. stocks in Nigeria and Cameroon. The model is described in detail in FAO, 2012.
Results
No results for the assessment model. But, based on other information available the Working Group considerer that the stock is fully exploited (FAO, 2020).
RESULTS: The model fit was not satisfactory with the data available.
DISCUSSION: The data of catch and CPUE do not have sufficient contrast to be able to apply any assessment model. The catches and CPUE follow the same trends. The data series and the new data need to be analysed and improved before the next meeting.
Sci Advice
As a precautionary measure the Working Group recommends that the total catch should not exceed the mean catch of the last five years (11 000 tonnes) (FAO, 2020).
Sources
FAO. 2019. Report of the FAO/CECAF Working Group on the Assessment of Demersal Resources – Subgroup South. Libreville, Gabon, 6–15 September 2017/Rapport du Groupe de travail sur l’évaluation des ressources démersales – Sous-groupe Sud. Libreville, Gabon, 6–15 septembre 2017. CECAF/ECAF series/ FAO/COPACE COPACE/PACE séries no.18/79. Rome.
http://www.fao.org/3/ca2739b/ca2739b.pdfFAO. 2019. Fishery Committee for the Eastern Central Atlantic, Report of the eighth session of the Scientific Sub-Committee, Abidjan, Côte d’Ivoire, 23–26 October 2018 / Comité des pêches pour l’Atlantique Centre-Est Rapport de la huitième session du Sous-Comité scientifique, Abidjan, Côte d’Ivoire, 23–26 octobre 2018. FAO Fisheries and Aquaculture Report / FAO Rapport sur les pêches et l’aquaculture No. 1265. Rome.
http://www.fao.org/3/ca5623b/ca5623b.pdfFAO. 2020. Report of the Twenty-Second Session of the Fishery Committee for the Eastern Central Atlantic, Libreville, Gabon, 17–19 September 2019. Rapport de la vingt-deuxième session du comité des pêches pour l’Atlantique centre-est, Libreville, Gabon, 17–19 septembre 2019. FAO Fisheries and Aquaculture Report / FAO, Rapport sur les pêches et l’aquaculture No. 1303. Rome.
http://www.fao.org/3/ca8000b/CA8000B.pdf Bibliography
All references to figures, tables and bibliography in the text are found within the source of information.