Data/hora: 08/06/2024 14:37:22

Provedor de dados: 	20	
País: 	Belgium	
Título: 	Seychelles demersal fishery an analysis of data relating to four key demersal species	
Autores: 	Mees, C. C.	
Data: 	2013-09-24	
Ano: 	1992	
Palavras-chave: 	Demersal fisheries; Fishery data; Fish catch statistics; Catch/effort; Yield predictions; Catch composition; Pristipomoides filamentosus; Aprion virescens; Lutjanus sebae; Epinephelus chlorostigma.	
Resumo: 	Seychelles demersal fishery is described based on historic catch and effort data, and on biological studies of four key species: Batrican (Pristipomoides filamentosus), Job Gris (Aprion virescens), Bourgeois (Lutjanus sebae), and Maconde (Epinephelus chlorostigma).  During the period 1985 - 1990 demersal species formed on average 33_310= of the total annual landings of the local fishing fleet.  Schooners and whalers were the most important boat types engaging in this fishery, and more recently, a mother ship dory fishing operation. Demersal species constituted 77_310= of all local fish exports over this period. In 1990 approximately 2,000 tonnes of demersal species were landed of which 500 tonnes were exported.  Lutjanids comprised 62_310= of the demersal landings, Lethrinids 22_310= and Serranids 16_310=. Of the Lutjanids the proportion of the catch represented by snappers tended to decrease whilst that of job fish increased over the period 1985 -1990, partly explained by a shift to deeper fishing grounds. Catch composition varied according to boat type and location fished. Generally whalers are restricted in range to inshore areas (10 miles radius of granitic islands) and the middle ground (30 - 50 miles offshore), Aprion virescens is the predominant lutjanid, and lethrinids are relatively more important in the catch than is the case with schooners. Schooners have a greater range and fish offshore banks and the peripheric ribbon of the plateau, catch predominantly lutjanids, and P. filamentosusis more important than other job fish species. Fishing locations were stratified by depth: shallow, 0 - 75 m; intermediate, 75 - 150 m; and deep, 150 m. The shallow stratum of the Mahe Plateau was sub stratified into inshore, offshore and trawls able areas. The inshore areas (0-35m) correspond to the area within 10 miles radius of the Mahe Plateau; the offshore areas include banks and the peripheric rim of the plateau at 36-75m; the trawl able grounds are flat sandy or rubble substrates on the plateau itself.  Some 40 _310= of the plateau surface area is not accounted for and may contain fish at densities below that which may be exploited by hand lines.  The principal fishing areas for demersal species where stock densities are greater are considered to be the offshore banks and peripheric rim and drop off. P. filamentosus is caught in the intermediate depth range, whilst the other study species relate to the shallow strata.  The maximum sustainable yield (MSY) for large demersal species available to a hand line fishery (i.e. not all demersal stocks) was determined by stratum from consideration of stock biomass determined from demersal trawling operations, from length cohort analyses of the key study species, and from stock depletion with intensive fishing on sea mounts and banks. Previous estimates of MSY are reviewed, and revised estimates are presented which supersede all previous estimates. Those given for the offshore banks are considered to be an underestimate, but insufficient data is available to determine to what extent the estimate should be increased.	
Tipo: 	Report	
Idioma: 	Inglês	
Identificador: 	http://hdl.handle.net/1834/5114	
Editor: 	Seychelles Fishing Authority

Victoria, Seychelles	
Relação: 	SFA Technical Report

19	
Formato: 	143	
Fonte: 	http://creativecommons.org/licenses/by-nc/3.0/