107 research outputs found
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
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
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
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
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