Pesquería de merluza negra en aguas de Marruecos 5 pp

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The black hake fishery in the Mauritanian EEZ: Analysis of the possible application of a 30 cm minimum

The fishery of black hake Merluccius spp. in the Mauritanian EEZ mainly comprises a Spanish trawler fleet, as well as some longliners. The highly specialised trawling fishery has diminished its effort, while its annual landings have remained stable, not surpassing 12 000 t. In the total annual catch, individuals measuring less than 30 cm do not represent more than 10% (with the exceptions of 1992 and 1993, when the highest recruitment was recorded), although this percentage is higher during the cold season. The evolution of both the yields and the average sizes of the landed hakes, which have increased since 1991, do not indicate an overexploited resource, especially if we take into account that the potential for hake exploitation off Mauritania has been estimated at 133000 tons annually. The implementation of a minimum legal length of 30 cm for Merluccius spp., which is contemplated in Mauritanian fishing regulations, would contradict the conditions of the present fishing agreement, which imposes a 60 mm mesh size and prohibits fishing within an offshore limit of 18 nautical miles. Due to mesh selectivity, to black hakes ' size-segregation with depth, and to the biological characteristics o f these species, which are small and highly migratory, Spanish trawlers will continue to catch individuals under 30 cm. Therefore, regulation by means of minimum size would not be an adequate conservation measure for black hakes in the Mauritanian EEZ.La pesquería de merluzas negras Merluccius spp. es ejercida en la ZEE mauritana por una flota española de arrastreros y por algunos palangreros, La pesquería de arrastre, altamente especializada, ha disminuido su esfuerzo, mientras sus capturas se han mantenido, no superando las 12 000 toneladas anuales. Aunque con valores mensuales mas elevados durante la estación fría, los ejemplares menores de 30 cm sólo han representado más del 10 % del total anual en 1992 y 1993, años de fuerte reclutamiento. La evolución de los rendimientos y de las tallas medias de las merluzas desembarcadas, que han aumentado desde 1991, no muestran una sobrexplotación del recurso, sobre todo si tenemos en cuenta que su potencial extraíble ha sido estimado en aguas mauritanas en 133000 toneladas anuales. La aplicación de la talla mínima de 30 cm contemplada por la legislación mauritana a Merluccius spp. entraría en contradicción con las condiciones del acuerdo de pesca vigente, que impone la malla de 60 mm y autoriza la pesca fuera de las 18 millas marinas. Debido a la selectividad de la malla, a la segregación de tallas con la profundidad que presentan las merluzas negras y a las características biológicas de estas especies, de pequeño tamaño y altamente migratorias, los arrastreros españoles seguirán capturando ejemplares menores de 30 cm. La regulación mediante la talla mínima no será, por consiguiente, una medida de conservación para las merluzas negras en la ZEE mauritana.Versión del editor0,000

Change in Elasmobranchs and Other Incidental Species in the Spanish Deepwater Black Hake Trawl Fishery off Mauritania (1992–2001)

From 1992 to 2001, by-catch that was landed from the Spanish deepwater trawl fishery for black hake off Mauritania was closely monitored. This is a highly specialised fishery, with two species of black hake (Merluccius senegalensis and Merluccius polli) constituting between 77–99% of total landings, which have annually averaged 9 300 tons over the past two decades. Landings of Sparidae were highest among by-catch species of commercial value, with the large-eye dentex, Dentex macrophthalmus being the most important until 1996, after which the family Lophiidae and others predominated. Next were the Elasmobranchii, including large demersal squalids and several species of rays, although their annual landings fell from 182 tons in 1992 to only 4 tons in 1999, rising to 37 tons in 2001. The present paper analyses these changes using by-catches retained in the black hake fishery. We believe that the decline could be due to a set of different factors: a change in depths fished, economic reasons and probable over-exploitation of both targeted species and by-catch. Elasmobranchs constituted only 0.1% of total landings in 1999, compared to 1.9% in 1992, although their contribution to total commercial by-catch was constant. Seasonality was clearly evident, with an absolute and proportional rise in elasmobranch by-catch during warm periods, reaching 75% of by-catch landings in some months, coinciding with a drop in total by-catch. These seasonal variations could be related to the migratory habits of the fishery's target species, black hake

Composition of Demersal Fish Assemblages in Deep-waters of the Western Guinean Gulf

Data from deep water hauls carried out during the Spanish Research trawling Survey 'GUINEA -90', conducted in Sierra Leone, Liberia, Ivory Coast and Ghana, between 100 and 700 m depth, were analysed. The taxonomic list of the survey showed a total of 91 fish species caught between 100 and 700 m depth. The maximum species richness and the highest abundances were found between 2000 and 300 m (60 species), depth range corresponding to the breaking of the continental shelf and to the upper part of the slope. Despite the local differences, the 'GUINEA -90' Survey showed the existence of fish assemblages

Las pesquerías de merluzas en los caladeros de África noroccidental: datos de base del año 1991

La merluza europea, Merluccius merluccius Linnaeus, 1758, es una de las especies objetivo de las pesquerías de arrastre mixto, palangre y volanta en aguas marroquíes, mientras que las merluzas negras, Merluccius senegalensis Cadenat, 1950, y Merluccius polli Cadenat, 1950, constituyen el único objetivo de la pesquería de bous en los caladeros de Marruecos, Mauritania y Senegal, y de las flotas de volanta y palangre. Durante 1991 faenaron en el caladero marroquí un total de 218 unidades que realizaron un esfuerzo de 28 624 días de pesca y unas capturas totales de 13 606 toneladas. El 34,5 % de las mismas correspondió a los desembarcos de merluza europea y el 7 % a los de merluza senegalesa. Las capturas de merluzas negras, Merluccius spp. constituyeron el 87 % de las 13 183 toneladas desembarcadas por la flota de bous, constituida en 1991 por 41 unidades, que ejercieron un esfuerzo de 5 085 días de pesca y obtuvieron unos rendimientos medios superiores a dos toneladas por día.European hake, Merluccius merluccius Linnaeus, 1758, is a target species of mixed trawl, longline and gillnet fisheries in Moroccan waters, whereas black hakes, Merluccius senegalensis Cadenat, 1950, and Merluccius polli Cadenat, 1950, are the sole target of the bous fishery in the Moroccan, Mauritanian and Senegalese fishing grounds, and of gillnet and longline fleets. During 1991, 218 units worked the Moroccan waters during 28 624 fishing days, with 13 606 tons total cathes. Of these landings, 34,5 % consist of European hake and 7 % correspond to Senegalese hake. Black hake, Merluccius spp. represented 87 % of the total catch landed by the bous fleet, formed in 1991 by 41 units, wich fished a total of 5 085 days, obtaining very high average yields, above two tonnes per fishing day.Versión del editor0,000

La pesquería española de arrastre de merluzas negras en aguas mauritanas: análisis de la serie histórica de datos

Las merluzas negras, Merluccius senegalensis Cadenat, 1950 y Merluccius cadenati Doutre, 1960, son capturadas en las costas del noroeste africano por una flota de arrastreros al fresco, con base en Cádiz, que faenan fundamentalmente, en la actualidad, en aguas de la ZEE mauritana. La firma, en julio de 1987, del Primer Acuerdo de Pesca entre la Comunidad Económica Europea (C.E.E) y la República Islámica de Mauritania (R.I.M.) ha establecido unas nuevas condiciones de pesca a la flota española, con la exigencia de las declaraciones de capturas, que han permitido un análisis más detallado de los datos, separándolos por caladero. En el presente trabajo se realiza la síntesis y análisis de la serie histórica de datos procedentes de la pesquería mauritana, proporcionando información sobre la descripción de los stocks de merluzas negras, flota pesquera y evolución de esfuerzos, capturas y rendimientos.Black hakes, Merluccius senegalensis Cadenat, 1950 and Merluccius cadenati Doutre, 1960, are caught on Northweast African coasts- by a fresh fish trawling fleet, with base in Cádiz, that fish at present principally in Mauritanian ZEE waters. The signature in July 1987 of the First Fishery Agreement between the EEC and the Islamic Republic of Mauritania have established new fishing conditions for the Spanish fleet, with the requirement in catch reports, that have allowed more detailed analysis of data, differentiating fishing grounds. The present paper synthetizes and analizes the historie data base of the Mauritanian fishery giving information about black hake stocks description, fishing fleet and efforts, catches and yields evolution.Versión del editor0,000

Distribución y aspectos biológicos de Pagellus bellottii bellottii Steindachner, 1882 (Sparidae) en el Golfo de Guinea

Durante el mes de abril de 1990 se efectuó la campaña de prospección pesquera demersal "Guinea 90", a bordo del B/C "Lagoapesca". La zona de trabajo comprendió la plataforma y el talud de Sierra Leona, Liberia, Costa de Marfil y Ghana, entre las isóbatas de 20 y 700 m de profundidad. La comunidad que presentó una mayor abundancia fue la de espáridos, siendo Pagellus bellottii bellottii Steindachner, 1882, la segunda especie dominante (7. 7% en peso de la captura total) después de Dentex angolensis Poll y Maul, 1953. Su distribución geográfica se extendió a toda el área de estudio (a excepción de la zona este de Sierra Leona) entre los límites batimétricos de 23 y 126 m. La máxima frecuencia y densidad se encontró en la banda comprendida entre 30 y 80 m. En Costa de Marfil se obtuvieron rendimientos de hasta 67.5 kg/1/2h, y un rendimiento medio de 17.2 kg/1/2h, lo que indicaría la elevada concentración de la especie en esta zona. Los ejemplares muestreados midieron entre 7 y 25 cm de longitud a la furca y presentaron distribuciones de tallas con dos modas, en 10-12 cm y en 15-16 cm, en toda el área, sin que fuera observada una segregación clara de las tallas con la profundidad. Los machos fueron casi siempre dominantes en las capturas, ofreciendo las "sex ratio" valores que variaron entre 1:0.33 y 1:1.06 (♂:♀). Los parámetros de la ecuación longitud a la furca - peso vivo, calculada con 302 ejemplares,fueron: a=0.010886 y b=3. 236784, con un r=O. 96098.Distribution and biological aspects of Pagellus bellottii bellottii Steindachner, 1882 (Sparidae), in the Guinean Gulf. During the month of April 1990, the fishing survey "Guinea 90" on board the F/V Lagoapesca was carried out. The sampled area corresponds to shelf and slope waters off the coast of Sierra Leone, Liberia, Cote d'Ivoire and Ghana, from 20 to 700 m in depth. The greatest abundance corresponded to the Sparidae Community. Pagellus bellottii bellottii Steindachner, 1882 was the second dominant species (7. 7% of the total catch weight). lts geographycal distribution was wide, spreading throughout nearly all the study area (except for the western zone of Sierra Leone) between 23 and 126 m of bath~ metric range. Both the frecuency and the density were the highest from the 30 to 80 m band. Yields in Cote d'Jvoire reached up 67.5 kg/ 1/2 h and mean yield of 17.2 kg/ 1/2 h, which would indicate the high species concentration in this zone. Sampled specimens ranged from 7 to 25 cm in fork length, showing size distribution with two modal classes, at 10-12 and 15-16 cm in the whole area; a clear size segregation in relation to depth was not observed. Males were always dominant in catches, with sex ratio values varyingjrom 1:0.33 to 1:1.06 (♂ :♀). Fork length - weight equation parameters, calculated with 302 specimens, were: a=0.010886 and b=3.236784, with r=0.96098.Versión del editor0,000

SPANISH DEEP-SEA FISHERIES IN THE CECAF AREA

Deep-seafisheriestakeplaceatgreatdepths(between200-2000meters),oncontinentalslopes,oceanicseamounts,ridgesystemsbanks. Thesefisheriestargetdemersal/benthicspeciesusingarangeofgearsincludingbottomandmid-watertrawls,potsandlonglines. Deep-seafisheriestakeplaceinbothexclusiveeconomiczones(EEZs)andinareasbeyondnationaljurisdiction(ABNJ)

Faunistic Composition of Catches from the Spanish Bottom-longline Fishery in Deep-waters of Mauritania

The Spanish bottom-longline fleet started fishing in Mauritania in the 1990s targeting the hakes. In November 2000, an experimental longliner survey was carried out. The data showed 85% of the catches were used commercially and 15% were discarded, 84% of the commercial catches belonged to two hakes, Merluccius senegalensis and Merluccius polli. The areas of greatest abundance and species richness seem to correspond to upwelling zones, located by satellite imagery, where the highest values of both chlorophyll concentrations and pelagic resources were detected