Demersal fishery resources in the western gulf of Guinea and Sherbro
Los recursos pesqueros demersales del sector occidental del golfo de Guinea y de Sherbro

FISHERY COMMITTEE FOR THE EASTERN CENTRAL ATLANTIC
COMITE DE PESCA PARA EL ATLANTICO CENTRO-ORIENTAL

with the assistance of the:
con la colaboración de la:
SECRETARIA GENERAL DE PESCA MARITIMA
and the/y del
INSTITUTO ESPANÕL DE OCEANOGRAFIA
(Spain/España)

CECAF/ECAF SERIES 91/55
SERIE CPACO/PACO 91/55

Report of the working group on the
demersal fishery resources in the western gulf of Guinea
and Sherbro statistical divisions

Informe del Grupo de trabajo sobre los
recursos pesqueros demersales en las divisiones
estadisticas del sector occidental del
golfo de Guinea y de Sherbro

held at the/reunido en el
CENTRE DE RECHERCHES OCEANOGRAPHIQUES
Abidjan, Côte d'Ivoire
24–28 September 1990/24–28 de septiembre de 1990

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS ORGANIZACION DE LAS NACIONES UNIDAS PARA LA AGRICULTURA Y LA ALIMENTACION Rome/Roma, 1992
© FAO

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1. INTRODUCTION

2. REVIEW OF PAST TRAWLING SURVEYS UNDERTAKEN IN THE AREA

3. THE EXECUTION AND MAIN RESULTS OF THE SURVEY OF THE CONTINENTAL SHELF AND SLOPE AREAS OFF CÔTE D'IVOIRE, GHANA, LIBERIA AND SIERRA LEONE (GUINEA-90 SURVEY)

5. STATISTICAL AND BIOLOGICAL DATA

5.2 Biological data collected during GUINEA-90 Survey

5.3 Length frequency data on some species of commercial importance

5.4 Upwelling indices

6. STOCK ASSESSMENT

6.1 National trawling surveys

6.2 Estimation of biomass for the GUINEA-90 Survey

6.3 Comparison of biomass estimates of GUINEA-90 and other surveys

6.3.1 Ghana

6.3.2 Côte d'Ivoire

6.4 Global production models

6.4.1 Côte d'Ivoire

6.4.2 Ghana

6.4.3 Sierra Leone

6.5 Analytical models

6.5.1 Côte d'Ivoire

7. RECOMMENDATIONS FOR RESEARCH AND MANAGEMENT

8. REFERENCES

LIST OF APPENDIXES

It should be noted that the appendixes are presented in the original language as submitted by the authors.

Appendix 1 List of Participants

Appendix 2 Agenda

Appendix 3 Surveys carried out in the waters of Ghana

Appendix 4 Surveys carried out in the waters of Sierra Leone

Appendix 5 Surveys carried out in the waters of Côte d'lvoire

Appendix 6 Surveys carried out in the waters of Liberia

Appendix 7 Total marine fishery production of Sierra Leone for the period 1971–1982

Appendix 8 Total annual catch and species composition of artisanal and industrial marine fisheries of Liberia for the period 1981–1985

Appendix 9 Los esparidos de la campaña “GUINEA-90”: Abundancia y distribucion. (The sparids in the GUINEA-90 Survey: abundance and distribution)

Appendix 10 Análisis de las capturas y distribucion de los cephalopodos de la campaña “GUINEA-90”. (Analysis of catches and distribution of the cephalopods in the GUINEA-90 Survey)

Appendix 11 Resultados obtenidos para la gamba (Parapenaeus longirostris, Lucas 1846) en la campaña “GUINEA-90”. (Results obtained for the shrimp, Parapenaeus longirostris in the GUINEA-90 Survey)

Appendix 12 Análisis de los resultados obtenidos para la gamba guineana (Parapenaeopsis atlantica, Balss 1914) en las pescas efectuadas durante la campaña “Guinea-90”. (Analysis of the results obtained in the Guinea shrimp Parapenaeopsis atlantica in the GUINEA-90 Survey)

LIST OF TABLES

Table 1. Characteristics and composition of the Ghanaian fishing fleets, 1980–1989

Table 2. Evolution of trawl fleet in Côte d'Ivoire from 1950 to 1989

Table 3. Catches of demersal finfishes from Ghanaian waters by the artisanal sector from 1972 to 1989

Table 4. Catches of demersal finfishes from Ghanaian waters by the industrial sector, 1974–1989

Table 5. Catches of demersal finfishes, corrected efforts and CPUE from Ghanaian waters by the semi-industrial fleet, 1972–1989

Table 6. Catches of demersal finfishes in Ghanaian waters (all fleets) from 1977–1989

Table 7. Total catches of Ivorian trawlers and shrimpers, catches made in Côte d'Ivoire and percentages of the total, 1955–1989

Table 8. Catches by species made by Ivorian trawlers/shrimpers on the continental shelf

Table 9. Estimated catches, efforts and standardized CPUE by bathymetric strata, of trawlers in Côte d'Ivoire, 1966 to 1988

Table 10. Ivorian catches in foreign waters and national waters, number of trawlers and standardized fishing efforts

Table 11. Catches of main demersal species landed in the port of Abidjan by line canoes during 1979 and 1988

Table 12. GUINEA-90 Survey: Length-weight relationship for Sparidae

Table 13. GUINEA-90 Survey: Total length-weight and fork length-weight relationships for different species

Table 14. GUINEA-90 Survey: Total length-fork length relationships for various species

Table 15. GUINEA-90 Survey: Relationships between cephalothoracic length-weight and total length-cephalothoracic length for P. longirostris and P. atlantica

Table 16. Minimum, maximum and modal sizes of selected fish species, GUINEA-90 and commercial trawlers in Abidjan

Table 17. Upwelling index and duration at Tema (1963–1989)

Table 18. Mean yields and variances obtained from the main CHALCI surveys

Table 19. GUINEA-90 Survey: Biomass by depth strata and sector

Table 20. GUINEA-90 Survey: Densities by depth strata and sector for total demersal species

Table 21. GUINEA-90 Survey: Catch specific composition in two net types

Table 22. Estimated biomass by strata and sector in GTS and GUINEA-90

Table 23. Estimated densities by strata and sector in GTS and GUINEA-90

Table 24. GUINEA-90 Survey: Estimated biomass of different species by depth and sector

Table 25. Catch rates (25.1) and densities (25.2) (1 and 2) of total demersal stocks and selected species obtained in trawling surveys on the continental shelf of Ghana, 1963–1990

Table 26. Catch of Balistes capriscus and number of specimens by depth and sector; GUINEA-90 Survey

Table 27. Lagocephalus laevigatus catches by strata and sector during GUINEA-90 Survey

Table 28. Lagocephalus laevigatus: Average weights by depth strata and sector during GUINEA-90 Survey

Table 29. Biomass and density of Lagocephalus laevigatus off Côte d'Ivoire and Ghana

Table 30. Catches of crustaceans by depth and sector; GUINEA-90 Survey

Table 31. Percentage of biomass of main fish groups during various surveys in Côte d'Ivoire

Table 32. Biomass of main fish groups during various surveys in Côte d'Ivoire - warm seasons

Table 33. Biomass of main fish groups during various surveys in Côte d'Ivoire - cold seasons

Table 34. Density of triggerfish and total demersal fishes in various surveys in Côte d'Ivoire - warm seasons

Table 35. Density of triggerfish and total demersal fishes in various surveys in Côte d'Ivoire - cold seasons

Table 36. Evolution of biomass of triggerfish in Côte d'Ivoire (1978–1990) pelagic and demersal surveys

Table 37. Upwelling indices by fortnight on the coast of Côte d'Ivoire, January-August 1990