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ProjectCopeMed II Occasional Papers 23 Current knowledge on sardine and hake exploitation and status in the Alboran Sea and the question of stock units identification 2017
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No Thumbnail AvailableProjectMarine fishery resources of Nigeria: A review of exploited fish stocks 1986
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No results found.In recent years there have been several attempts to review the fishery statistical system and the state of the fishery resources of Nigeria. Nobody has found the exercise easy, for there are discrepancies between the ideal planned statistical sampling scheme and the one effectively operated. And, as details on the current system are not available, it is difficult to determine the accuracy or precision of the reported catch figures and to debias them accordingly. In these circumstances, the re still exist discrepancies between reported combined catches of the artisanal and industrial sectors and estimated yield potential of the Nigerian continental shelf. Some workers have tried to use some results of limited studies, partial sampling and isolated productivity values as rules of thumb, hoping that the inshore fisheries are more or less homogeneous and constant, and also that such results obligingly apply to the entire coastline. The trouble is, however, that the Nigeri an marine fisheries are characterized by temporal and spatial variations, and anyone studying them will soon realize the need for more basic data from the various sectors of the fishery. The complexity of the aquatic ecosystem poses a great challenge to natural science. In the first instance, a comprehensive survey of fishing units and exploited multiple species stocks presents a formidable obstacle. It is therefore understandable that fishery biologists investigating the dynamics of coastal ecosystems have to abstract general principles from the interrelationships of the many species. More recent data on activities of artisanal and industrial fleets reveal rather complicated interactions. (...) -
No Thumbnail AvailableProjectMarine Fishery Resources of Sierra Leone: A review of exploited fish stocks 1986
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No results found.Sierra Leone is located in the southwestern sector of the great bulge of West Africa. It lies between 7°N and 10°N and is bordered on the North and East by the Republic of Guinea, and on the South by Liberia. Sierra Leone has a territorial sea limit of 200 mi. Its coastline is about 506 km and is characterized by extensive mangrove swamps, a number of estuaries and rivers that are navigable for short distances. The hydrographic regime of Sierra Leone waters is characterized by a relatively st able, shallow thermocline lying at mid-shelf depth and affecting the distribution of fish. Seasonal changes are due to the following effects of the monsoonal wet season: high river discharges, reduced surface water salinities, lowered solar radiation and a slight dip in mixed layer temperatures. The multiple stock fisheries are exploited with a variety of fishing gears (gillnets, cast nets, beach seines, trawls, purse seines, ringnets, traps and hooks), operated from different artisanal canoes a nd industrial fishing boats. Before the introduction of trawlers in 1955, fishing was purely artisanal. Even today, the catch of the artisanal fishery accounts for more than 80% of the total national fish landings.
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