Horse mackerel and other carangids - Southern Area of Eastern Central Atlantic|
| Fact Sheet Title Fact Sheet |
| | | Horse mackerel and other carangids - Southern Area of Eastern Central Atlantic |
| | Data Ownership | | This document provided, maintained and owned by Food and Agriculture Organization (FAO) , is part of CECAF Stock Status Reports data collection. |
| | ident Block | ident Block | | | | Species List: | | Species Ref: en - False scad, fr - Comète coussut, es - Macarela real |
| Species Ref: en - Cunene horse mackerel, fr - Chinchard du Cunène, es - Jurel de Cunene, ru - Ставрида западноафриканская |
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| ident Block Horse mackerel and other carangids - Southern Area of Eastern Central Atlantic
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| fao Div |
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| 34.3.3 | Sherbro |
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| 34.3.4 | Western Gulf of Guinea |
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| 34.3.5 | Central Gulf of Guinea |
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| 34.3.6 | Southern Gulf of Guinea |
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| 47.1.1 | Cape Palmeirinhas |
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| 47.1.2 | Cape Salinas |
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| 47.1.3 | Cunene |
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| fao Sub Div |
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| 34.3.13 | Atlantic, East central / 34.3.13 |
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| | Aq Res | Biological Stock: No
Value: Sub-Regional
Reference year: 2008 |
| 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. |
| | | | | | Aq Res State Trend Trachurus trecae - North (Gabon, Guinea, Sierra Leone and Liberia) Trachurus trecae - South (Gabon, Congo, DR Congo and Angola) Decapterus spp. - North (Guinea-Bissau, Guinea, Sierra Leone and Liberia) Habitat Bio Climatic Zone: Tropical. Bottom Type: Unspecified. Depth Zone: Coastal (0 m - 50 m); Shelf (50 m - 200 m); Slope (200 m - 1000 m). Horizontal Dist: Neritic; Oceanic. Vertical Dist: Pelagic. Geo Dist Geo Dist: Shared between nations Water Area Overview Spatial Scale: Sub-Regional Water Area Overview  | | Water Area Overview Horse mackerel and other carangids - Southern Area of Eastern Central Atlantic
| fao Div | 34.3.3: Sherbro | | 34.3.4: Western Gulf of Guinea | | 34.3.5: Central Gulf of Guinea | | 34.3.6: Southern Gulf of Guinea | | 47.1.1: Cape Palmeirinhas | | 47.1.2: Cape Salinas | | 47.1.3: Cunene | | fao Sub Div | 34.3.13: Atlantic, East central / 34.3.13 |
| | | | | | Water Area Overview |
Water Area OverviewHorse mackerel and other carangids - Southern Area of Eastern Central Atlantic Aq Res Struct Biological Stock: No Whilst waiting for more detailed information on stock identity of the carangid species in the southern CECAF region, the Working Group decided to consider five stocks: the northern stock (Guinea-Bissau, Guinea, Sierra Leone and Liberia), the western stock (Côte d’Ivoire, Ghana, Togo and Benin), the central stock (Nigeria and Cameroon), the Sao Tome stock and the southern stock (Gabon, DR Congo, Congo and Angola). Exploit Catch and effort data for the five stocks with total observed catches between 1990 and 2008 are shown in Tables 5.2.1a,b and c and Figures 5.2.1.a,b,c. Total catchIt can be seen that, for Decapterus spp., the catches are basically all from the industrial fishery in the northern stock (Guinea and Sierra Leone) with an annual average of about 4 000 tonnes. The majority of catches in the southern CECAF region (mainly Decapterus rhonchus) are taken in Guinea. A large decrease can be seen in all catches from around 5 700 tonnes in 1996 to around 2 000 tonnes in 2004 followed by a recovery in 2005 and 2006. For the group of Trachurus spp. species, most of the Trachurus trecae are caught in the stocks of the northern, western and central regions and the Trachurus spp. are caught in the southern stock (notably in the Angolan zone). A worrying decrease can be seen over the whole southern CECAF region, going from over 65 000 tonnes in 1990 to less than 7 000 tonnes in 2004. It should however be noted that an increasing trend in catches can be seen from 2003 in the western stock. The other carangid species that are generally exploited in the region are Selene dorsalis, Chloroscombrus chrysurus and the Caranx spp. species. Total catches of these species have seen an increasing trend, rising from 1 300 tonnes in 1993 to 15 000 tonnes in 2008. Effort In Guinea and Sierra Leone these species are mainly fished by encircling gillnets and driftnets in the artisanal fishery. In Ghana, Togo, Benin, Nigeria and Cameroon, small carangids are mainly exploited by the beach seine and the purse seine. Most of the industrial fleets’ effort is concentrated in the Guinean EEZ. The large pelagic trawlers that target horse mackerel come from eastern European countries (Russian Federation and Ukraine). The nominal effort of this fleet (fishing days) decreased overall from over 600 fishing days in 1996 to around 400 days in 2004, then recovered increasing to 900 days in 2005 before falling again to 600 days in 2007 (Table 5.2.2). Bio Assess Data The model requires a time series of total catch and abundance indices of the stock. The estimates of total catch obtained by summing catches from different fleets from countries were used. The global model was applied to the Decapterus spp. data from the northern stock (Guinea-Bissau, Guinea, Sierra Leone and Liberia) using the CPUEs of the industrial pelagic trawlers of Guinea (period 1995– 2007). For Trachurus trecae, the northern stock (Guinea-Bissau and Liberia) and the southern stock (Congo, Gabon and Angola) were considered. In the northern region, the model was applied to the CPUE of the industrial trawlers of Guinea (period 1995 stock 2007) and to the CPUE of the artisanal fishery of Liberia (1997–2008). In the southern region, the model was applied to the stock data using the biomass indexes of acoustic surveys of the R/V DR. FRIDTJOF NANSEN as the abundance index. For Caranx spp. the model was applied to the Sao Tome stock using the CPUE of the artisanal fishery. Assess Models Type: Biomass-aggregated The Schaefer dynamic production model was used on an Excel spreadsheet (model described in Appendix II). Schaefer dynamic production model Results The global models applied to the data for the Decapterus spp. species in the northern stock, T. trecae species in the northern and southern zone were not considered because the indices used are not representative of the change in biomass of these different zones. No diagnosis can thus be established on the basis of these models. DiscussionBased on these models it was not possible to draw conclusions on the state of the stocks of the different species studied. In the case of the northern stocks, the species are the most exploited by Guinea-Bissau and Guinea. In Guinea-Bissau, the data collection is irregular while in Guinea, an estimated proportionality coefficient based on the data for one survey was applied to the landings with a view to estimating the catches of each of the species. Additional surveys are therefore necessary. Moreover, the sharp declining trends in the catches of the two species ( Decapterus spp. and Trachurus trecae) at least over the last three years suggest a precautionary approach in the exploitation of the stocks. As concerns the southern stocks, the most exploited Carangid species is T. trecae in Angola. However the landings of this species are not fully recorded. Nevertheless, the biomass and average length series in Angola which began in 1985 show a decline. The estimated MSY using the Cadima formula is lower than the catch of the last year and furthermore, 90 percent of the biomass recorded in 2009 is made up of undersized individuals (length <21 cm, pers. comm. 2009). All these observations also indicate the adoption of a precautionary approach. Sci Advice Future research In order to reduce uncertainties surrounding the assessment, the Working Group recommends carrying out the following research:
- Support sampling programmes in order that they cover total catch of all the main carangid species, including horse mackerel, for all fleets in all countries of the southern CECAF region.
- Continue biological data collection for biological studies (growth, reproduction, feeding) on the main carangid species and make these data available to the Working Group by the next meeting.
- Begin sampling catches and discards onboard all vessels fishing horse mackerel due to problems arising from under-declaration of catch, especially of juveniles.
for Management consideration Due to limitations in the models obtained and uncertainties surrounding the data, whilst waiting for more investigations on the fisheries and survey data, the Working Group suggests that the following precautionary measures be adopted:
The catch of the Decapterus spp. species group in the northern countries should not exceed the 3 000 tonnes level (last year’s value).
The catch of the T. trecae species should not exceed the level of 10 000 tonnes (last year’s value) in the northern countries and in the southern countries the effort targetting this species should be reduced. Sources Report of the FAO/CECAF Working Group on the Assessment of Small Pelagic Fish – Subgroup South Accra, Ghana, 19–28 October 2009./Rapport du Groupe de travail FAO/COPACE sur l'évaluation des petits poissons pélagiques – Sous-groupe Sud Accra, Ghana, 19-28 octobre 2009.  http://www.fao.org/docrep/018/i2909b/i2909b.pdf |
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