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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. -
Book (series)Report of the FAO/RECOFI Workshop on Fishery Stock Indicators and Stock Status. Tehran, the Islamic Republic of Iran, 26-29 July 2009. 2011
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No results found.This document contains the report of the FAO/RECOFI Regional Workshop on Fishery Stock Indicators and Stock Status that was held in Tehran, Islamic Republic of Iran, from 26 to 29 July 2009. At the fourth session (2007) of RECOFI held in Jeddah, Kingdom of Saudi Arabia, the Secretariat prepared for the minimum requirements of stock assessment. The Commission recognized that those requirements were too complicated and noted a shortage of expertise. The effort was resumed at the second m eeting of the Working Group on Fisheries Management (WGFM) in 2008 where a shift to a pragmatic approach based on an Ecosystem Approach to Fisheries management (EAF) with adaptive procedures was recommended. The objective of the Workshop was to review the availability of data on the biology of the identified priority resources, catch and effort statistics for the relevant fisheries, other socio-economic statistics, results of stock assessments and other relevant research activities i n member countries; to identify the major gaps in knowledge and information, priority areas for regional cooperation and potential joint activities; and to formulate the RECOFI work program for regional cooperation in assessment of stocks and fishery status appraisal in the short and medium term. Employing a simple matrix of Susceptibility Productivity Analysis (PSA), the participants identified three areas of particular concern. These are the ecosystem-wide impact of shrimp trawls, th e exploitation of neritic demersal assemblages as well as sharks as indicators of the overall level impact of exploitation, and, thirdly, the stock status of a selected priority species, Scomberomorus commerson, for which historic data are available. The Workshop concluded with a set of recommendations to the WGFM that focused on improvement of data collection and monitoring capacity and members¿ contributions to scientific knowledge through joint activities.
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