REPORT OF THE AD HOC WORKING GROUP ON THE COASTAL PELAGIC STOCKS OF THE WESTERN GULF OF GUINEA (Côte d'Ivoire-Ghana-Togo-Benin)
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REPORT OF THE AD HOC WORKING GROUP ON THE COASTAL PELAGIC STOCKS OF THE WESTERN GULF OF GUINEA (Côte d'Ivoire-Ghana-Togo-Benin) |
| CECAF/ECAF/SERIES 91/56 |
Held at the Centre de Recherches Océanographique,
Abidjan, Côte d'Ivoire
10–16 December, 1990
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FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 1992
© FAO 1992
| FAO. Report of the ad hoc Working Group on the Coastal Pelagic Stocks of the Western Gulf of Guinea (Côte d'Ivoire, Ghana, Togo, Benin), held at the Centre de Recherches Océanographique, Abidjan, Côte d'Ivoire, 10–16 December 1990. CECAF/ECAF/Series. N° 91/56. Rome, FAO. 1992. 153 p. |
| ABSTRACT |
| The objective of the working group was to update the statistics on the stocks of small pelagic fishes in the western Gulf of Guinea (Côte d'Ivoire, Ghana, Togo, Benin), refine the data, acquire a better understanding of the biology of the species and identify methods for a better evaluation of the stocks. |
| The four species of concern to the Working Group were: Sardinella aurita, S.maderensis, Scomber japonicus and Engraulis encrasicolus. |
| The sensitivity of coastal pelagic species to environmental factors was emphasized and upwellings, discharge of coastal rivers into the sea, coastal currents, winds were related to the fisheries. The fisheries were described and in addition to the analysis of catch and CPUE data, a time-space analysis of catch statistics, yield and length frequencies were carried out, particularly for S. aurita and S.maderensis. The Working Group reviewed the biological data available and the hypotheses already put forward on the nature of the stocks of the different species. Stocks assessments were based on CPUE and length frequencies data. |
| The Working Group concluded that the recent modification of the productivity of the ecosystem was favourable to the fisheries and high catch rates and CPUE of Sardinella aurita show that the related stock (or stocks) are recovering. The Working Group recommended to pursue the study of relevant physical and oceanographical factors, to strengthen statistics, biology and data processing. Multivariate analysis were also recommended to establish for the principal species, the typology of strata defined by fishing zone-month-gear within which reliable abundance index should be calculated. |
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At the kind invitation of the Government of Côte d'Ivoire and the Centre de Recherches Océanographiques (CRO), the ad hoc working group on the stocks of small pelagic fishes in the western Gulf of Guinea (Côte d'Ivoire-Ghana-Togo-Benin), was held in Abidjan from 10 to 15 December 1990. This sixth regional meeting (1976–1979–1981–1987–1989) was an expression of the value of the regional cooperation which aims at understanding the biology of these species with a view to rationalizing the exploitation of this common resource.
In December 1987 a new impulse was given to this cooperation which, for the first time, made a tentative prediction of the evolution of the Sardinella aurita resource. Fortunately, the collapse of the Ghana-Côte d'Ivoire S. aurita stock, predicted by the coordinating group of May 1989, did not occur. This error of judgment evidenced that the dynamics of these stocks must once again be the object of diligent research. The meetings of 1987 and 1989 concluded, in particular, that detailed analysis on a fine spatio-temporal scale will be necessary to clarify a number of phenomena which the global analysis was unable to bring to light. A preliminary team was set up to collect data for the past ten years on an as detailed as possible spatio-temporal basis and to make such data available to the working group in computer form.
Scientists from Ghana, Benin, Côte d'Ivoire and the CECAF programme participated in this working group (See Annex 1). Dr F.-x. Bard, Director of CRO, opened the meeting and praised the model of regional cooperation existing among the four countries. He was nominated chairman with Mr M. Taconet as the main rapporteur.
The proposed agenda (Annex 2) was adopted during the first morning. It gives the objective of this working group as: updating the global statistics and focusing on the refined data, acquiring a better understanding of the biology of the species, and identifying methods that will enable a better evaluation of the stocks.
The four species of concern to the working group were the two sardinella species, Sardinella aurita and S. maderensis, the chub or Spanish mackerel, Scomber japonicus, and the anchovy Engraulis encrasicolus.