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Ona Basin, the westernmost oceanic basin in the southern Scotia Sea, is affected by the opposite flows of Circumpolar Deep Water (CDW) and Weddell Sea Deep Water (WSDW); thus , it represent s a key location for exploring seafloor morphologies influenced by bottom currents. The present study aims to capture the spatial arrangement of recent subsurface contourite features , assuming a latitudinal influence of water masses and the interactions between along - and downslope processes, in order to contribute to the knowledge of regional deepwater flow pathways and to the sedimentary model of small sediment -starved oceanic basins. To this end, the investigation combine s an interpretation of multibeam bathymetry and parametric echo sounder seismic data complemented with hydrological data. The distribution of morpho -sedimentary features in Ona Basin reveals two major domains. The southern margin of the basin can be regarded as a mixed/hybrid system containing abundant sediment drifts with channels and contourite moats and a lateral continuity interrupted by downslope morphologies. In contrast, the northern abyssal setting comprises relatively homogeneous large sheeted drifts with superimposed sediment waves, mounded drifts , and several scattered erosive features, likely reflecting the more distinct influence of deepwater contourite processes. Our work demonstrates that tectonic features in the southern basin control the interaction between deepwater along - and downslope processes, as the westward flow of the WSDW is deflected, channelized , and intensified along its westward route. In the northern region, the study indicates an overall clockwise rotation of the WSDW flow, with the spatial and vertical variability of CDW and WSDW affecting the distribution of bottom -current features around seamounts and/or structural highs. The results underscore the importance of sloping interphases in the water mass vertical structure, the degree of basin confinement, and the influen

A morphological and seismic-stratigraphic analysis of the Gulf of Cadiz area near the Strait of Gibraltar is presented in this work, focused on the sedimentary evolution of the upper and proximal middle-continental slope since the Mid-Pleistocene. Based on the analysis of seismic reflection profiles and swath bathymetry data, this work analyses the close influence of the activity of buried and outcropping diapiric ridges and late Quaternary sea-level changes on the evolution of contouritic features related to the Mediterranean Outflow Water (MOW) and Eastern North Atlantic Central Water (ENACW), gravitational features and fluid-escape structures. The stratigraphic architecture reveals that, under active diapiric deformation, the upper slope plastered drift grew during low sea-level stages, when sediment supply was high and the ENACW swept the upper slope, contrasting with the present-day highstand situation dominated by northwest-trending MOW flow. The south-estward ENACW flow forced asymmetry and lateral migration of gullies incised in the plastered drift. Two evolutionary stages have been established: 1) After the Mid Pleistocene, activity of diapirs with a NE trend determined the location of the deepest depressions which were infilled by plastered contouritic drifts; 2) Between Late Quaternary and present, a drastic change of buried diapirs growth pattern and orientation to a NW trend enhanced slope-derived gravitational processes affecting the bottom current dynamics. Adjustments to tectonic changes led to a phase of plastered drift growth on the upper slope during which depocenters varied their distribution and orientation. In a long-term the structural control on sedimentation shows a northwestward displacement of deformation, resulting in an overall extension of the contourite depositional system to the NW. In a short-term, sea-level changes favored drift deposition, gullies incision and the strengthening of water masses. This work evidences the importance of, A morphological and seismic-stratigraphic analysis of the Gulf of Cadiz area near the Strait of Gibraltar is presented in this work, focused on the sedimentary evolution of the upper and proximal middle-continental slope since the Mid-Pleistocene. Based on the analysis of seismic reflection profiles and swath bathymetry data, this work analyses the close influence of the activity of buried and outcropping diapiric ridges and late Quaternary sea-level changes on the evolution of contouritic features related to the Mediterranean Outflow Water (MOW) and Eastern North Atlantic Central Water (ENACW), gravitational features and fluid-escape structures. The stratigraphic architecture reveals that, under active diapiric deformation, the upper slope plastered drift grew during low sea-level stages, when sediment supply was high and the ENACW swept the upper slope, contrasting with the present-day highstand situation dominated by northwest-trending MOW flow. The south-estward ENACW flow forced asymmetry and lateral migration of gullies incised in the plastered drift. Two evolutionary stages have been established: 1) After the Mid Pleistocene, activity of diapirs with a NE trend determined the location of the deepest depressions which were infilled by plastered contouritic drifts; 2) Between Late Quaternary and present, a drastic change of buried diapirs growth pattern and orientation to a NW trend enhanced slope-derived gravitational processes affecting the bottom current dynamics. Adjustments to tectonic changes led to a phase of plastered drift growth on the upper slope during which depocenters varied their distribution and orientation. In a long-term the structural control on sedimentation shows a northwestward displacement of deformation, resulting in an overall extension of the contourite depositional system to the NW. In a short-term, sea-level changes favored drift deposition, gullies incision and the strengthening of water masses. This work evidences the importance of

High habitat diversity was observed on the Seco de los Olivos Seamount (SW Mediterranean Sea), a Site of Community Importance belonging to the Spanish marine Natura 2000 Network. Thirteen epibenthic habitats were identified by analysing 55 Remotely Operated Vehicle (ROV) transects from 76 m to 700 m depth and derived data from multibeam bathymetry and high resolution seismic profiles. Habitat identification was based on a combination of assemblages of habitat-forming species and the environmental characteristics supporting their distribution. Depth and slope were identified as the main significant factors structuring epibenthic assemblages. The high diversity and patchiness of habitats found on the Seco de los Olivos Seamount can be explained by the high environmental variability resulting from its wide geomorphologic diversity, where flat summits, steep flanks, rocky outcrops and sedimentary moats are combined. The distribution of benthic habitats at this seamount is likely a combination of suitable ecological conditions, local recruitment, feeding strategies and attachment mechanisms. Knowledge on the occurrence of habitats in areas of natural importance is crucial to species and habitats conservation and to develop proper monitoring and management programs aimed at fulfilling European regulation requirements.

The deep-water rose shrimp, Parapenaeus longirostris, is a demersal species found in the Mediterranean and Atlantic Seas. The study area comprises three Spanish CGPM-FAO Geographic Sub-Areas (GSA’s): Alboran Sea (GSA 1), the Balearic Islands (GSA 5) and Northern Spain (GSA 6). Data from annual commercial landings and MEDITS_ES surveys biomass index per haul (kg/km2) were analyzed for the 1994–2016 period. Mapping the spatial distribution of biomass makes evident its occurrence in all the areas, particularly in GSA 1 and also in the South of GSA 6. Depth distribution shows that presence ranged from 55 to 741 m, being mainly located between 200 to 300 m depth. Biomass index average shows large yearly oscillations, particularly in GSA 1 decreasing beyond 2009. In contrast biomass indices in GSA 6 (South and North) and in GSA 5 increased steeply and synchronously from 2006 onwards, rebuilding the populations to similar levels of a previously observed maximum.

The latest Green Paper on the EU Common Fisheries Policy (CFP) identified the high level of discards in Europe as one of the structural weaknesses of the current CFP. The new CFP introduces a discard ban in European waters, with an obligation to land all regulated species. The fishing management system in the Mediterranean is based on effort control and technical measures, and this is raising some particular concerns about the effective implementation of the discard ban. With the exception of bluefin tuna (Thunnus thynnus, Scombridae), there are no quotas in the Mediterranean and this regulation affects all regulated species with the minimum landing size. Under these circumstances, the discard ban may lead to an increase in the amount of juvenile fish caught, because such catches are not counted against a given quota, as is the case in the Atlantic fisheries, and thus, there is no incentive to avoid catching them. On the contrary, the obligation to land the juveniles that are now discarded and their subsequent fishmeal processing might even become commercially interesting. One possible consequence of the new regulation may be an increase in the illegal marketing of fish below the minimum size. The landing, storage and transportation of juveniles will all be legal, and this may simplify their commercialization via the black market. The discard ban and landing obligation should be accompanied by other measures to ensure their successful implementation, including the agreement of the fishing sector to comply with the rules and regulations

The STECF was tasked with an analysis of the likely effects of proposed management plans for the Southwestern (Bay of Biscay and Iberia) and Northwestern (Celtic sea) waters. Quantitative analyses were carried out to compare the likely effect of those management plans and of the direct application of the CFP on both stocks and fleets involved in these fisheries. Based on the results of simulations of the provisions of the proposed management plans, STECF concluded that, setting fishing opportunities in line with single-species FMSY ranges will provide managers with additional flexibility compared to the basic provisions of the 2013 CFP. Such flexibility is likely to help alleviate the problem of mismatches in quota availability in mixed-species fisheries thereby reducing the risk of early closure of some fisheries due to choke species. Adopting FMSY ranges will therefore increase the likelihood that desired exploitation rates will be achieved and will reduce the risk that some fishing fleets will go out of business. STECF considers that it is crucial that managers take note that persistent fishing at the upper limits of the FMSY ranges across all or most stocks simultaneously negates the flexibility introduced by the FMSY ranges and greatly increases the risk of overfishing. Such an approach will also increase the risk that the objectives of the CFP will not be achieved. STECF concludes that single species biomass safeguards for all stocks should be maintained to provide a basic level of protection. STECF notes that for the fleets affected by the SWW MAP, those providing the highest employment are generally not dependent to a great extent on the species that will be regulated through the MAP proposals. STECF notes that in the NWW there are some fleets which provide significant levels of employment and seem to be very dependent on the species that will be regulated through the MAP proposals. Nevertheless, there are a number of fleets in the NWW area that are not incl

La gamba roja (Aristeus antennatus, Risso 1816) es una especie ampliamente distribuida en el Atlántico oriental desde Portugal hasta las islas Azores y las de Cabo Verde, alcanzando en su extremo septentrional el Banco de Galicia. Presente en el Índico hasta las Maldivas, se distribuye ampliamente por las tres cuencas del Mediterráneo a excepción del Adriático y Egeo. En el Mediterráneo español, los resultados obtenidos sugieren que, durante la primavera, la distribución de A. antennatus en las zonas de estudio y hasta los 800 m de profundidad, es muy estable a lo largo del tiempo. Su población está repartida por el talud, tanto peninsular como insular, con características muy homogéneas entre sí, y con pequeñas variaciones no significativas entre las islas Baleares. La especie se distribuye entre los 400 y 800 m de profundidad en el talud peninsular, y entre los 600 y 750 m en el de las Baleares. Si bien la distribución de las variables poblacionales es bastante homogénea, se observa una clara tendencia a aumentar los valores de abundancia y de biomasa conforme disminuye la temperatura y aumenta la salinidad, siendo éstas variables y especialmente la salinidad las que mas afectan a la distribución de la biomasa de la especie. Considerada como estenoterma y estenohalina, su distribución está relacionada con las fluctuaciones del Agua Levantina Intermedia (LIW).

Comparative multispecies studies allow contrasting the effect of past and present oceanographic pro- 30 cesses on phylogeographic patterns. In the present study, a fragment of the COI gene was analyzed in 31 seven decapod crustacean species from five families and with different bathymetric distributions. A total 32 of 769 individuals were sampled along the Atlantic–Mediterranean transition area in order to test the 33 effect of three putative barriers to gene flow: Strait of Gibraltar, Almeria–Oran Front and Ibiza Channel. 34 A significant effect of the Strait of Gibraltar was found in the crabs Liocarcinus depurator and Macropipus 35 tuberculatus. The Ibiza Channel had a significant effect for L. depurator. However, the Almeria–Oran front 36 was not found to have a significant effect on any of the studied species. Higher levels of population struc- 37 ture were found in shallow-water species, although the number of species sampled should be increased 38 to obtain a conclusive pattern. The haplotypes within the different species coalesced at times that could 39 be related with past climatic events occurring before, during and after the last glacial maximum. Given 40 the large diversity of phylogeographic patterns obtained within decapods, it is concluded that both his- 41 torical and contemporary processes (marine current patterns, bathymetry and life-history traits) shape 42 the phylogeographic patterns of these crustaceans.

We analyzed the influence of some abiotic variables in the biomass distribution of these species using survey data collected over four years (2006-2009) in the Catalano-Levantine coast of Spain. The preliminary results show that variables such as time (year) and latitude feebly affect the biomass distribution of these species. Depth, by itself, is not as significant as believed, masking the influence of other variables. M. barbatus biomass distribution seems to be especially influenced by salinity and, to a lesser extent, by temperature, while only temperature seems to have a significant effect on the M. surmuletus biomass distribution. These results are consistent with the bathymetric distribution of both species, with M. barbatus showing affinity for low salinity waters and M. surmuletus for warmer waters, which may contribute to the segregation of the species., Se ha analizado la influencia de algunos factores abióticos en la distribución de las biomasas de las especies utilizando datos de campaña recogidos a lo largo de cuatro años (2006-2009) en la costa catalano-levantina de España. Los resultados preliminares muestran que las distribuciones de la biomasa de las dos especies se ven afectadas débilmente por la época del año y la latitud. La profundidad no resulta tan significativa como se esperaba, enmascarando la influencia de otras variables. La distribución de la biomasa de M. barbatus está especialmente afectada por la salinidad y, en menor medida, por la temperatura; y en el caso de M. surmulentus, parece que únicamente la temperatura tiene un efecto significativo en la distribución de la biomasa. Estos resultados son consistentes con la distribución batimétrica de ambas especies, mostrando una afinidad por aguas de salinidad reducida en el caso de M. barbatus, y por aguas cálidas en el caso de M. surmuletus, que puede contribuir a la segregación de las especies.

Deep-water shrimps show large inter-annual fluctuations in biomass. We analysed the influence of some abiotic factors in these fluctuations using survey data (2006-2009). While P. longirostris biomass was feebly affected by the T-S of the water masses, these factors, particularly salinity, seemed to have a significant effect on A. antennatus a species considered to be stenothermal and stenohaline, whose biomass distribution showed a direct relationship with the Levantine Intermediate Water.

[EN] A series of 57 (600-750 m) and 32 (1184-1320 m) hauls were compiled to compare data from four trawl types in analyses of the species composition and diversity of deep benthopelagic fish and decapods off the Catalonian coasts (western Mediterranean). Two 1-warp trawls (OTSB-14 and OTMS-25) and two 2-warp trawls (a commercial trawl [CT] and a GOC73) were used, from hauls performed between 1988 and 2007 were compiled. At 600-750 m the OTSB-14 hauls were separated in multi-dimensional scaling (MDS) from hauls performed with MTS-25, CT, and GOC73. Ordination of hauls along DIM1 of MDS was significantly correlated (Spearman’s r) with mesh size at codend, bridle length, and vertical opening of trawls. When CT and GOC73 were compared with MTS-25, the most dissimilar species were Aristeus antennatus, Galeus melastomus and Trachyrhynchus scabrus. A particular case was A. antennatus, with a significantly higher abundance in MTS-25 catches than the rest of the trawls. At 1200 m the OTSB-14 and MTS-25 hauls were segregated in MDS analysis. DIM2 was correlated with the sampling period (month), indicating a temporal effect on haul composition. At 1200 m the main dissimilarities between OTSB-14 and MTS-25 were marked by Alepocephalus rostratus and A. antennatus (caught with MTS-25), and by Cataetyx alleni, the Notacanthidae Notacanthus bonapartei and Polyacanthonotus rissoanus, and Plesionika acanthonotus (caught with OTSB-14). As a conclusion, OTSB-14 showed a significantly higher abundance in catches than MTS-25, CT and GOC73, and a higher S (number of species) and J (equitability) than MTS-25. On the lower slope seasonality influenced trawl comparisons; however, it is likely that MTS-25, with higher vertical height than OTSB-14, caught the benthopelagic fish A. rostratus more efficiently, explaining the higher biomass from MTS-25 there. MTS-25 positively selected A. antennatus, in parallel to a negative catchability for other species, [ES] Se recopilaron datos sobre la abundancia de peces y crustáceos decápodos de un total de 57 (600-750 m) y 32 (1184-1320 m) lances de una zona concreta de las costas de Cataluña (Mediterráneo Occidental) para comparar la composición y diversidad de estas comunidades en función de la utilización de cuatro tipos distintos de artes de arrastre bentónicos. Dos tipos de arte de arrastre de 1 cable (OTSB-14 y MTS-25) y dos más de 2 cables (un arte comercial, CT y un GOC73) fueron utilizados en lances efectuados entre 1988 y 2007. 600-750 m los lances efectuados con el 14 se segregaron (en un análisis MDS) de los lances realizados con el MTS-25, el CT, y el GOC73. La ordenación de los lances a lo largo del primer eje (DIM1) del MDS presentó una correlación significativa (r de Spearman) con la luz de malla en el sobrecopo, con la longitud de las malletas de los artes y con sus aberturas verticales. Al comparar los modelos CT y GOC73 con el MTS-25 las especies con mayor disimilaridad fueron Aristeus antennatus, Galeus melastomus y Trachyrhynchus scabrus. A. antennatus constituyó un caso particular con una densidad significativamente mayor en los lances de MTS-25 en comparación con el resto de artes utilizados. 1200-1300 m los lances de OTSB-14 y de MTS-25 se segregaron en los análisis MDS. El segundo eje (DIM2) se correlacionó con el perido de muestreo (mes), indicando un efecto estacional en la composición de especies. A 1200-1300m. la principal disimilaridad entre la composición del OTSB-14 y del MTS-25 vino marcada por Alepocephalus rostratus y por A. antennatus (capturados preferentemente con el MTS-25) y por Cataetyx alleni, por los Notacanthidae Notacanthus bonapartei y Polyacanthonotus rissoanus, y por Plesionika acanthonotus (capturados con el 14). En conclusión el 14 mostró una mayor abundancia en sus capturas que el MTS-25, el CT y el GOC73, mientras la S (número de especies) y la J (equitabilidad) fueron también significativamente más elevados en los lances con

Se analiza el comportamiento de los artes provistos con copos de malla de 40 mm rómbica y cuadrada y su influencia en la captura de cuatro especies demersales de importancia comercial: merluza Merluccius merluccius (L., 1758), bacaladilla Micromesistius poutassou (Risso, 1826), salmonete de fango Mullus barbatus L., 1758 y salmonete de roca Mullus surmuletus L., 1758. Las capturas totales obtenidas (copo más sobrecopo) fueron similares con ambos tipos de malla y, aunque la tasa de retención en el copo fue un 20 % mayor en el caso de la malla rómbica, la tasa de descarte fue un 30 % menor con la malla cuadrada. Las tallas de primera captura obtenidas con los copos de malla cuadrada son mayores que las obtenidas con los de malla rómbica para las cuatro especies analizadas, obteniéndose, así mismo, un rango de selección (25-75 %) y un factor de aselección mayores. Los rendimientos no muestran diferencias significativas entre ambos tipos de malla en ninguna de las especies consideradas. En todos los casos, las tasas de descarte para estas especies fueron muy bajas. El uso de la malla cuadrada de 40 mm produciría efectos positivos en la pesquería, debido al incremento de las tallas de primera captura, y en el ecosistema, debido a la reducción de los descartes de especies no comerciales., Yield, selectivity parameters, and discard rates for diamond- and square- shaped 40 mm cod-end mesh size are analysed for a number of important commercial fish species: european hake Merluccius merluccius (L., 1758), striped red mullet Mullus barbatus L., 1758, red mullet Mullus surmuletus L., 1758 and blue whiting Micromesistius poutassou (Risso, 1826). Although total catches were similar with both types of mesh, the catch retained was 20 % higher for the diamond mesh, whereas discard rates were 30 % lower with the square mesh. The size at first capture obtained with square mesh was higher and selection range (25-75 %) and selection factor were higher compared with those obtained using diamond mesh. Discard rates for the species considered were negligible in both cases. The use of the 40 mm square-shaped cod-end mesh could be beneficial to the fishery due to the increase of the size at the first capture for the species considered and to the ecosystem, because the reduction of discards rates of noncommercial species.

Se analiza el comportamiento de los artes provistos con copos de 40 mm de malla rómbica y cuadrada, y su influencia en cuatro especies demersales de importancia comercial: merluza, bacaladilla, salmonete de fango y salmonete de roca. Las capturas totales obtenidas (copo más sobrecopo) fueron similares con ambos tipos de malla, aunque la tasa de retención en el copo fue un 20% mayor en el caso de la malla rómbica; por el contrario la tasa de descarte fue un 30% menor con la malla cuadrada. Las tallas de primera captura obtenidas con los copos de malla cuadrada son mayores que las obtenidas con los de malla rómbica para las cuatro especies analizadas, obteniéndose asimismo un rango de selección (25-75%) y un factor de selección mayores. Los rendimientos no muestran diferencias significativas entre ambos tipos de malla en ninguna de las especies consideradas. En todos los casos las tasas de descarte para estas especies fueron muy bajas. El uso de la malla cuadrada de 40 mm produciría efectos positivos en la pesquería debido al incremento de las tallas de primera captura y en el ecosistema debido a la reducción de los descartes de especies no comerciales., Yield, selectivity parameters an discard rates for diamond and square shaped 40 mm cod-end mesh size are analysed for some important commercial fishes (european hake, striped red mullet, red mullet and blue whiting). Although total catches were similar with both types of mesh, retained catch was 20% higher for the diamond mesh whereas discard rates were lower with the square mesh. Size at the first capture obtained with the square mesh is higher and selection range (25-75%) and selection factor higher with respect to those obtained for the diamond mesh. Discard rates for the species considered are negligible in both cases. The use of the 40 mm square shaped cod-end mesh could produce benefits to the fishery due to the increase of the size at the first capture for the species considered, and to the ecosystem because the reduction of discards rates of non commercial species.

En esta tesis se presenta un estudio de la biología de la gamba roja y se analiza su explotación como recurso renovable, en tres zonas próximas del Mediterráneo español: Golfo de Alicante, Canal de Ibiza y Golfo de Vera. Para ello se recolectaron ejemplares, mensualmente y a lo largo de un periodo de 8 años, desde 1992 hasta 1999, tanto en las lonjas de desembarco de la flota comercial de distintos puertos representativos de cada zona (Villajoyosa, Santa Pola y Garrucha), como a bordo de embarcaciones que frecuentaron los distintos caladeros; por otra parte se recopilaron datos de la pesquería (desembarcos, esfuerzo) en cada zona a lo largo del periodo de estudio. Se identifican las zonas y profundidades de explotación, caracterizándose un total de 17 caladeros, definiendo los rangos de explotación entre los 350 y 1.153 m de profundidad, estando caracterizados por la influencia del Agua Levantina Intermedia (LIW) hasta los 700 m y del Agua Profunda (DW) a partir de ésta profundidad. A. antennatus se puede definir como una especie estenoterma y estenohalina, de amplio rango de distribución batimétrica y geográfica. Si bien la estructura de la población explotada no muestra grandes diferencias entre las zonas, con las hembras dominando en la proporción sexual de las capturas (PS= 0.80), existen diferencias significativas en sus tallas medias y en sus crecimientos, tanto entre sexos como entre zonas. En general las hembras resultan más robustas y mayores que los machos, pudiendo éstas alcanzar los cinco años, mientras que los machos sólo alcanzan los tres años de longevidad. También existen diferencias entre sexos en la reproducción, aunque ésta sigue el mismo patrón en las tres zonas, localizándose en los meses estivales. Las tallas de primera maduración encontradas para ambos sexos (17 mm de Lc y 22 mm de Lc en machos y hembras respectivamente), resultan menores que las consignadas por otros autores en zonas próximas, y se atribuyen a una mayor contribución de tallas, This thesis presents a study of the biology of the red shrimp Aristeus antennatus and its exploitation as a renewable resource was analyzed in three neighbouring areas of the Spanish Mediterranean: the Gulf of Alicante, Ibiza Channel and the Gulf of Vera. Specimens were gathered monthly during a period of 8 years, from 1992 until 1999, from the fish markets used for landings by the commercial fleets of various representative ports in each area (Villajoyosa, Santa Pola and Garrucha), as well as from on board vessels that visited the different fishing grounds. In addition, data from the fishery (e.g. landings, effort) were compiled for each area during the study period. The exploitation areas and their depths were identified, and a total of 17 fishing grounds were characterised. The exploitation ranges between depths of 350 and 1,153 m were characterised by the influence of the Levantine Intermediate Water (LIW) down to 700 m and the Deep Water (DW) below this depth. A. antennatus could be defined as a stenothermic and stenohaline species, with a wide bathymetric and geographical distribution. Although the structure of the exploited population did not show large differences between the areas, with the females dominating in the sexual proportion of the catches (SP = 0.80), significant differences existed in their average sizes and growth, both between sexes and areas. In general, the females were more robust and larger than the males, being able to reach five years old, whereas the males only achieved three years old. Differences in reproduction, which occurred in the summer months, also existed between sexes, although this had the same pattern in the three areas. The sizes at first maturity found for both sexes (17 mm Cl and 22 mm Cl in males and females, respectively), were less than those reported by other authors in neighbouring areas, and were attributed to a larger contribution of small sizes in the catches. The exploitation patterns and activity groups of the fl

En esta tesis se presenta un estudio de la biología de la gamba roja y se analiza su explotación como recurso renovable, en tres zonas próximas del mediterráneo español. Para ello se recolectaron ejemplares a lo largo de un periodo de 8 años, desde 1992 hasta 1999, tanto en las lonjas de desembarco de la flota comercial de distintos puertos representativos de cada zona, como a bordo de embarcaciones que frecuentaron los distintos caladeros; por otra parte se recopilaron datos de la pesquería (desembarcos, esfuerzo) en cada zona a lo largo del periodo de estudio. Se identifican las zonas y profundidades de explotación, y si bien la estructura de la población explotada no muestra grandes diferencias entre las zonas, con las hembras dominando en la proporción sexual de las capturas, existen diferencias en sus tallas y en sus crecimientos, tanto entre sexos como entre zonas. También existen diferencias, entre sexos, en la reproducción, aunque resulta muy similar en las tres zonas. También existen diferencias, entre sexos, en la reproducción, aunque resulta muy similar en las tres zonas, localizándose en los meses estivales. Las tallas de primera maduración encontradas para ambos sexos, resultan menores que las consignadas por otros autores en zonas próximas. Se identifican los patrones de explotación y los grupos de actividad de las flotas, caracterizándolos, y obteniendo índices de abundancia estandarizados. Se analiza el estado de explotación del recurso por medio de análisis de cohortes de talla, rendimiento por recluta y análisis de la población virtual, calibrando con índices de abundancia tanto derivados de capturas por unidad de esfuerzo estandarizadas como obtenidos en campañas de prospección, no encontrando cambios en el patrón de explotación a lo largo del tiempo, destacándose la estabilidad de los reclutamientos; se concluye que el recurso se encuentra en un estado de sobrexplotación, no detectado previamente por otros autores en zonas próximas, y se establec

The artisanal fleet operating in the Alicante Gulf was analysed from data collected at the Santa Pola port using, multivariate analysis and GLM, by first time in this type of fishery. Monthly landings by boat from 1994 to 2002 were used to describe activity groups, identify discriminant species, characterise catch composition by gear and obtain a derived abundance index for selected species. The results suggested that the fishery was more or less stable throughout the years.

En esta tesis se presenta un estudio de la biología de la gamba roja y se analiza su explotación como recurso renovable, en tres zonas próximas del mediterráneo español. Para ello se recolectaron ejemplares a lo largo de un periodo de 8 años, desde 1992 hasta 1999, tanto en las lonjas de desembarco de la flota comercial de distintos puertos representativos de cada zona, como a bordo de embarcaciones que frecuentaron los distintos caladeros; por otra parte se recopilaron datos de la pesquería (desembarcos, esfuerzo) en cada zona a lo largo del periodo de estudio. Se identifican las zonas y profundidades de explotación, y si bien la estructura de la población explotada no muestra grandes diferencias entre las zonas, con las hembras dominando en la proporción sexual de las capturas, existen diferencias en sus tallas y en sus crecimientos, tanto entre sexos como entre zonas. También existen diferencias, entre sexos, en la reproducción, aunque resulta muy similar en las tres zonas. También existen diferencias, entre sexos, en la reproducción, aunque resulta muy similar en las tres zonas, localizándose en los meses estivales. Las tallas de primera maduración encontradas para ambos sexos, resultan menores que las consignadas por otros autores en zonas próximas. Se identifican los patrones de explotación y los grupos de actividad de las flotas, caracterizándolos, y obteniendo índices de abundancia estandarizados. Se analiza el estado de explotación del recurso por medio de análisis de cohortes de talla, rendimiento por recluta y análisis de la población virtual, calibrando con índices de abundancia tanto derivados de capturas por unidad de esfuerzo estandarizadas como obtenidos en campañas de prospección, no encontrando cambios en el patrón de explotación a lo largo del tiempo, destacándose la estabilidad de los reclutamientos; se concluye que el recurso se encuentra en un estado de sobrexplotación, no detectado previamente por otros autores en zonas próximas, y se establec

The red shrimp (Aristeus antennatus) is a target species of a deep trawl fishery in the Gulf of Alicante. This paper describes the fishery by following the activity of this trawl fleet between 1992 and 1999. Principal Components Analysis (PCA) of specific catch compositions identified five main components that explained 92% of the variability, and the catches were grouped into three main species: red shrimp, hake and blue whiting. Hierarchical Clustering Grouping of the percentage species catch composition allowed the fleet to be considered as two main groups, according to monthly landings and by differentiating the origin of the catches (slope or shelf). The species composition of the catch and the red shrimp catch rates (CPUE) differed between the two fleet groups. The application of Generalised Linear Modelling (GLM) to the CPUE series gave consistent indices of abundance. The fleet group, year and season had significant effects on shrimp catch rates, with the fleet group being the most important, and these models explained up to 62% of the total deviance. The abundance indices showed little variation from 1992, although 1994 had the highest value and 1997-1998 the lowest. Comparison with survey indices showed similar trends, while mean uncorrected CPUE differed. Monthly variations of shrimp indices showed a lower abundance in summer, which was attributed to the reproductive patterns of the species. As a result, the use of some fleet grouping techniques is recommended before standardising CPUEs to obtain trends or to calibrate assessment in a fishery.

The hake (M. merluccius) is a target species of the Mediterranean trawl fleets. In this study, its growth was compared by two means: whole otolith readings and length frequency distribution analysis. Two growth hypotheses, fast and slow, were assumed using the results of otolith readings: (1) two rings were formed every year and (2) a single ring was formed every year. The monthly length distributions covered the period from 1992 to 1998, and the otoliths were obtained from monthly samplings between 1992 and 1995. The variability observed in the results for the number of rings counted was shown especially in the range of lengths for each group of individuals that had the same number of rings. A high correlation was found between the rings counted in the otoliths and the length of the individual in cm. The sex factor did not influence the relationship, unless the sexually undifferentiated individuals were included. The best fit with the growth data according to the length frequencies occurred in the two-ring hypothesis (Hypothesis 1), meaning faster growth rates than had been accepted till now, especially in females. We suggest the consideration of the hypothesis of faster growth in future studies.

The distribution and biological features of anglerfish (Lophius piscatorius and L. budegassa) in the Mediterranean Sea were analysed from trawl surveys data (MEDITS project, years 1994-1999). The above-mentioned species were widely distributed in the Mediterranean, but differences in abundance were found according to geographic sectors and depths. Most of the collected specimens belonged to the first length cohorts and length distributions also differed at macroarea levels. Mean sizes at female sexual maturity were estimated at 68.5 cm and 66.2 cm total length, respectively for L. piscatorius and L. budegassa

The pink shrimp (Aristeus antennatus) is a demersal species that is object of a very specific trawl fishery. In this paper on describe, for first time in this area, some biometric relationships, growth parameters and reproductive patterns of the specie, showing a sexual size dimorphism, with a negative allometry in its growth, being higher in females. Females dominated in catch composition. The spawning period occurred between the months of June to September; the maturation stage, both for males and females, take place within the first year of life.