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The two-dimensional hydrodynamic flood models are computationally expensive, especially in large-scale watersheds, which limits their application when several simulation runs are required or in large-scale catchments. More recently, the literature presented a significant increase in the use of Deep Learning as an alternative to hydrodynamic models because of their computational efficiency. However, studies show that Artificial Neural Networks (ANN) applications for flood prediction lack the ability to predict floods outside the training datasets satisfactorily. In this study, we used a conditional generative adversarial network (cGAN) aiming to generalize pluvial flood predictions (cGAN-Flood) in catchments not included in the training dataset. Our approach uses two generators to solve a rain-on-grid problem by first identifying wet cells and then calculating the water depths. cGAN-Flood distributes a target flood volume (vt) in a given catchment, which can be calculated via water balance from any hydrological simulations. Our approach was trained on ten and tested on five urban catchments. The testing areas have distinct characteristics and were compared to HEC-RAS outputs for different rainfall magnitudes and surface roughness. The averages of the root square mean error (RSME) and critical success index (CSI) were 0.12m and 70.1%, respectively. The successful water depths predictions in the testing areas show that cGAN-Flood can generalize. cGAN-Flood, combined with an SWMM model to compute vt, was 250 times faster than HEC-RAS. Due to its computational efficiency and accuracy, cGAN-Flood can be applied when fast simulations are necessary, and it can be a viable for flood forecasts in large-scale watersheds., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

This investigation concerns the ways in which young children (ages 5 to 8) compare quantities and how they work out the difference between them. The experiments involved children's understanding of mathematical problems and their ability to make use of graphical information in such problems. Each child was shown a series of illustrations, each representing two sets of quantities where the numerical difference was represented either discontinuously or continuously. The children were asked Equalize and Compare questions about each illustration and had to choose the correct answer from the set which represented the choice stimuli. Children's use of strategies was observed. In Experiment 1 (5-to-8-year-olds), only the younger children (5-to-6-year-olds) were observed to perform much more accurately on the Equalize-type question than on the Compare in both discontinuous and continuous conditions. The 7-to-8-year-olds reached a ceiling effect in performance, suggesting that by this age they can already deal with different types of arithmetic problems and with different types of graphical information. Experiment 2 (5-to-6-year-olds) repeated the first experiment presenting the graphical information on a microcomputer, but the discontinuous and continuous conditions were subdivided on the basis of the use of the comparative term "more" or "less". Children are helped significantly by the use of discontinuous material and by the use of "more" in Equalize-type questions only. These results did not support those of Experiment 1 where the Equalize and Compare difference was significant with both discontinuous and continuous material. Experiment 3 introduced part-whole manipulations in order to find out why Compare questions are more difficult to solve than Equalize questions. Five-to-6-year-olds' performance on Compare word problems was not affected by this type of manipulation. Experiment 4 explored the Equalize and Compare difference by presenting the material in a story-telling context. Again, the 5-to-6-year-olds' performance on Compare word problems was not affected by this type of manipulation. However, Equalize questions were helped by the use of the comparative term "more", as in Experiments 2 and 3, and by the presentation of discontinuous material, as in Experiment 2. Experiments 5 and 6 explored children's (5-to-8-year-olds) performance on Equalize- and Compare-type questions using spatial imagery manipulations. Experiment 5 involved manipulations of display in order to examine children's relative ease with Equalize word problems. Again, children's performance was not affected by this type of manipulation. In addition to the display manipulations, Experiment 6 introduced different level manipulations. However, in this experiment, the comparative pair was not represented in the choice stimuli. Children's performance on Compare word problems improved. There was no sign of the Equalize and Compare distinction which may be due to the fact that there was no representation of the comparative pair. The results show that the Equalize and Compare difference is due to a combination of their inherent structural and linguistic factors. Furthermore, the difficulty children have with Compare word problems is non-number-specific, but their relative ease with Equalize word problems is number-specific. Such type results indicate that children represent these two problems very differently.

Objectives The purpose of this study was to develop a new brief, comprehensive geriatric assessment scale for older patients diagnosed with different hematological malignancies, the Geriatric Assessment in Hematology (GAH scale), and to determine its psychometric properties. Materials and Methods The 30-item GAH scale was designed through a multi-step process to cover 8 relevant dimensions. This is an observational study conducted in 363 patients aged ≥ 65 years, newly diagnosed with different hematological malignancies (myelodysplasic syndrome/acute myeloblastic leukemia, multiple myeloma, or chronic lymphocytic leukemia), and treatment-naive. The scale psychometric validation process included the analyses of feasibility, floor and ceiling effect, validity and reliability criteria. Results Mean time taken to complete the GAH scale was 11.9 ± 4.7 min that improved through a learning-curve effect. Almost 90% of patients completed all items, and no floor or ceiling effects were identified. Criterion validity was supported by reasonable correlations between the GAH scale dimensions and three contrast variables (global health visual analogue scale, ECOG and Karnofsky), except for comorbidities. Factor analysis (supported by the scree plot) revealed nine factors that explained almost 60% of the total variance. Moderate internal consistency reliability was found (Cronbach's α: 0.610), and test–retest was excellent (ICC coefficients, 0.695–0.928). Conclusion Our study suggests that the GAH scale is a valid, internally reliable and a consistent tool to assess health status in older patients with different hematological malignancies. Future large studies should confirm whether the GAH scale may be a tool to improve clinical decision-making in older patients with hematological malignancies.

Se trata de un libro que pretende divulgar a la sociedad las principales investigaciones multidisciplinares llevadas a cabo por el Instituto Español de Oceanografía durante su primer siglo de vida, y dar a conocer la historia del organismo, de su Sede Central y de los nueve centros oceanográficos repartidos por los litorales mediterráneo y atlántico, en la península y archipiélagos., Kongsberg 200

Over the past years, the development of capillary electrophoresis (CE) and microchip electrophoresis (ME) systems has grown due to instrumental simplicity and wide application. In both CE and ME, the application of a high voltage (HV) is a crucial step in the electrokinetic (EK) injection and separation processes. Particularly on ME devices, EK injection is often performed with three different modes: gated, pinched, and unpinched. In all these cases, different potential values may be applied to one or multiple channels to control the injection of small sample volumes as well as the separation process. For this reason, the construction of reliable HV power supplies (HVPS) is required. This review covers the advances of the development of commercial and laboratory-built HVPS for CE and ME. Moreover, it intends to be a guide for new developers of electrophoresis instrumentation. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recruitment variability is an important component of the dynamics of Ibe-rian sardine (Sardine pilchardus). Since 2006, poor recruitment has led to a fall in stock biomass, the latest in a series of such crises for sardine fisheries. Understanding the mechanism behind recruitment fluctuations has been the objective of many previous studies, which proposed various relationships between recruitment and environmen-tal variables. However, such studies face several analytical challenges including short time series and autocorrelated data. We carry out new analysis of empirical relation-ships with environmental series using statistical methods designed to cope with these issues, including dynamic factor analysis, generalised additive models and mixed models. Our results identify relationships between recruitment and global (number of sunspots), regional (NAOAutumn) and local (winter wind strength, SST and upwel-ling) environmental variables. Separating these series into trend and noise components permitted further investigation of the nature of the relationships. Whereas the other three environmental variables were related to the trend in recruitment, SST was re-lated to residual variation around the trend, providing stronger evidence for a causal link, possible mechanisms for which are discussed. After removal of trend and cyclic components, recruitment also shows a weak relationship with the previous year´s spawning stock biomass.

The Iberian sardine ( Sardine pilchardus ) is a good example of the typical life strategy of small pelagic fish species around the world: short life span, fast growth and long spawning season, which in the case of the Iberian stock presents two peaks (in winter and spring). This life strategy makes new year classes ve ry dependent on the right environmental conditions to survive the early life stages. Egg and larval survival relies on the right oceanographic mechanisms, to ensure retention in favourable areas, and availability of food. Dispersal of eggs and larvae serio usly reduces their survival and decreases the chances of a good new year class. Because of this dependency on environmental conditions in early life, there is no relationship between the stock size (measured as SSB) and recruitment. Previous studies have e xplored the relationship between environmental variables, at large and local spatial scales, and sardine recruitment in the Galician and Portuguese sardine fishery but have faced two main analytical challenges: short time series and autocorrelated data. We carry out new analysis using statistical methods designed to cope with these challenges, including Dynamic factor Analysis and mixed modelling, to identify and characterise relationships between sardine populations (recruitment, spawning stock biomass, an d (to extend the time series) fishery landings in the area) and a series of global, regional and local environmental variables.

We report a record of the largest known specimen of Ommastrephes bartramii. It was an almost mature female, with dorsal mantle length (ML) of 1020 mm and weighing around 35 kg, caught by a Spanish fishing vessel in October 2007 on a surface long-line in the Eastern Tropical Pacific. Growth increments on a statolith indicate an age of 492-512 days. The stomach was full and contained beaks of ommastrephid squids and of a small pelagic octopus (Japetella spp.), and remains of mackerel (possibly bait from the long-line) and unidentified fish., En este trabajo se presenta información sobre el mayor ejemplar de Ommastrephes bartramii descrito hasta la actualidad. Se trata de una hembra casi madura, cuya longitud dorsal del manto es de 1020 mm y con un peso total de aproximadamente 35 kg, capturada en octubre de 2007 por un pesquero español utilizando palangre de superficie en el Pacífico Tropical Este. Los incrementos de crecimiento observados en un estatolito indican una edad comprendida entre 492 y 512 días. El estómago estaba lleno y contenía picos de potas (omastréfidos) y de un pulpo pelágico pequeño (Japatella spp.), así como restos de caballas (posiblemente cebo del palangre) y de otros peces que no pudieron ser identificados., Sí

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A specimen of the neon flying squid Ommastrephes bartramii (LeSueur, 1821) was caught using a surface longline in the Eastern Tropical Pacific Ocean in October 2007. The animal was frozen whole on board and landed in Vigo, where it was defrosted and examined. The squid represents the largest specimen of this species yet recorded, with a mantle length of 102 cm (30+ kg), compared to the recorded maximum of 80 cm (25 kg). The specimen was a mature female, with an ovary weight of around 500 g. There appeared to be spermatangia stored in the buccal membrane. Its stomach contents included beaks of ommastrephid cephalopods and bones of a mackerel-like (scombrid) fish. Age of the animal is also studied.

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Los resultados obtenidos del marcado y posterior recaptura de los ejemplares son una herramienta muy valiosa para contribuir a mejorar el conocimiento de la biología y ecología de una especie, examinando ciertos aspectos como son: el crecimiento, los movimientos o migraciones, la mortalidad o supervivencia, la abundancia y distribución de la especie, el hábitat y diferenciación de poblaciones o stocks. Actualmente la técnica de marcado se aplica a muchas especies, tanto terrestres como marinas, pertenecientes a diversos grupos zoológicos: peces, crustáceos, reptiles, moluscos y mamíferos. Este libro repasa algunos ejemplos de marcado de especies marinas de interés comercial. No todas las especies pueden ser marcadas, porque es necesario cumplir una serie de requisitos para poder llevar a cabo con éxito un experimento de marcado. En uno de los apartados de esta guía, se describen los distintos aspectos a tener en cuenta para obtener buenos resultados. Se describen los principales proyectos de marcado actualmente en ejecución o en marcha llevados a cabo por el Instituto Español de Oceanografía (IEO). En primer lugar, se describe brevemente la especie, su distribución, crecimiento, reproducción, alimentación, etc. A continuación, se presenta la información del marcado, es decir, campañas realizadas, número de ejemplares marcados y algunos de los resultados obtenidos hasta la fecha a partir de las recapturas disponibles. En algunas especies, los programas de marcado se llevan realizando desde hace más de 20 años, como es el caso del atún rojo, por lo que la información disponible es bastante amplia. En otros casos por el contrario como la merluza, los proyectos son relativamente recientes, no obstante los resultados son bastante interesantes y prometedores., Nowadays many different marine animals are being tagged. This book summarizes recent tagging programs carried out by the Spanish Institute of Oceanography (IEO). Although the objectives of these various studies mainly depend on the species and each project in particular, the general aim is to better understand the biology and ecology of these animals the structure and dynamics of their populations and their capacity to respond to human activities. This book provides an overview of different aspects of this technique such as a brief history of tagging, the types of tags currently used, including both conventional and electronic tags, where and how to put them on the marine animals, some recommendations regarding how to perform a tagging survey and where to go or what to do if anyone recovers a tagged fish or marine animal. The book then summarizes the main species tagged by the IEO, making a short description of their biology followed by some of the results obtained from tagging studies undertaken until now. Other applications are to know the spatial distribution (spawning or feeding areas), estimate growth parameters, mortality and survival rates, longevity, the size of the population or identifying stocks. Nowadays the advances in electronics have also open new fields such us the possibility of tracking an animal and knowing its habitat preferences and behaviour. Besides some of these tags have the capacity of recording this information during long periods and sending the data from long distances even without the need to recover the animal. Tagging activities constitute a very useful tool to improve the knowledge of many species and contribute to their management and conservation. For that reason this methodology is included in many IEO projects in which other activities like the monitoring of the fishery (landings, fishing effort, fleet characteristics, fishing areas, biological sampling, etc.) are carried out. Some projects are related with coastal pelagic fisheries including anchovy, sardine and mackerel or oceanic pelagic fisheries like tuna and billfish species and pelagic sharks. Others are focused on benthic and demersal species such as hake, black spot seabream, anglerfish, flatfish, etc. Nevertheless not all species can be tagged, as they have to survive being caught and handled before being release. For this reason, tagging techniques may not easily be applied to some species.

Results of the Spanish spring acoustic survey PELACUS0407, carried out from the 27th March to the 23rd April 2007, indicated a stock biomass of 96,390 tons of sardine (1482 million fish) in northwest and northern Spanish waters. The main bulk of the resource was found in Galician waters (ICES sub-areas IXa-N, VIIIc-W) and consisted of age 3 fish (fish born in 2004). Age 3 fish also predominated in ICES sub-area VIIIcE-w but not in the eastern part of the surveyed area, where older fish were more abundant (ICES sub-area VIIIcE-e). The abundance and biomass obtained from PELACUS0407 are similar to the values estimated from the last 2 surveys (with a slight increase in the biomass but not in the number of fish). These figures seem to indicate that the last strong sardine recruitment (2004) probably halted the downward trend in stock size apparent since 2001 in Spanish waters. However, there is also evidence that the 2004 recruitment in the surveyed area was not as strong as the previous recruitment peak in 2000, since both biomass and abundance values are at their lowest since 2001. In addition, the area occupied by the sardine stock in Spanish waters appears also to have diminished continuously since 2001, which could make the resource even more vulnerable to fishing and/or predation. PELACUS0407 also obtained data on the distribution of sardine eggs and their number in the surveyed area: eggs were found in larger quantities and over a wider area than previously recorded by CUFES in the PELACUS series (2000-2007)

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Annex 6, The highest catches of the Iberian sardine stock are taken from the southern part of Galician waters (NW corner of the Iberian Peninsula) and northern Portugal. Landings are mainly composed of younger fish, which reflects the proximity of the main recruitment area to the fishery grounds. Since 1978 there has been an improvement in the knowledge of the biology and stock dynamics of sardine around the Atlantic Iberian waters. In the last decade a consecutive years with poor recruitments result in a depletion of stock below limits previously recorded. The recruitment processes seem to be driven by oceanographic (local) and climatic (global) events, this dependence on both phenomena may explain the fluctuations on the landings in the sardine fisheries in Atlantic Iberian waters. Given the dependence of the fishery in this area on the strength of the recruitment, different relationship between biotic components (spawning stock size, recruitment, landings and recruitment landings) and abiotic: climatic indices (NAO-winter, Gulf Stream and AMO) and local oceanographic coastal events (upwelling and poleward current) were analysed. In the analysis of the abiotic series in the period (1978–2005), there appears to be a shift in the general trend in 1995. In addition at the end of the nineties several consecutive years with poor recruitment result in a depletion of the stock below limits previously recorded as well as changes in the distribution area. Before the shift was observed the recruitment variability could be explain by the environmental variables, but since then the correlation is poor.

Data on the occurrence of sardine (Sardina pilchardus) eggs from 42 national ichthyoplankton surveys along the European Atlantic coast were collated in order to describe the spawning habitat and spawning distribution of sardine in recent decades (1985–2005). A modification of existing spawning habitat characterisation techniques and a newly developed method to compare the probability of egg presence across surveys carried out with different sampling gears were used. Results showed that sardine spawning off the Atlantic European coast is mainly restricted to the shelf area, with the main geographical range being between the Strait of Gibraltar (the southern limit of data available for this analysis) and the middle part of the Armorican shelf (latitude around 47.5 North), and along a temperature range of 12–17 C. Spawning grounds within these limits show a nearly continuous geographical distribution, covering a large proportion of the shelf of the Iberian peninsula and adjacent waters, except for: (1) a persistent gap at the north west corner of the Iberian peninsula, (2) a small secondary break at the Spanish–French border in the inner part of the Bay of Biscay and (3) at the south west corner of the peninsula where there is a narrowing of the shelf width. These discontinuities were used to separate spawning into four nuclei and to describe the changes in spawning distribution in the time series. The relative importance of each nucleus and the degree of separation between adjacent nuclei varies between years, with the exception of the permanent gap at the northwest corner of the Iberian peninsula, which is persistent throughout the time series. Year to year changes in the proportion of the potential spawning habitat in which spawning actually occurred, changing from around 60% before the mid 1990s to around 40% thereafter, and did not show any relationship with spawning stock biomass. Evolution of potential habitat occupation over the Armorican shelf shows larger variability than that observed in the Iberian peninsula, with percentages of occupation ranging from around 30% up to nearly 80% of the shelf in recent years (within the limitations of the relatively sparse data for this region).

The solvolysis reactivity of benzoyl chlorides entails a high sensitivity on medium properties. A systematic study of the reaction of a series of these substrates, varying the electron-withdrawing character of the substituent, has been performed in nonionic microemulsions. The kinetic effects due to variation of microemulsion compositions can be assigned to modifications in system properties, to be precise, to modifications in interface properties. Microemulsion properties that are obtained from kinetic analysis of solvolysis show a good agreement with the characterization of the microemulsion that was made via 1H NMR and solvatochromic fluorescence probes. Benzoyl chlorides with electron-donating groups react through a dissociative mechanism, whereas electron-withdrawing groups favor an associative mechanism. A comparative analysis of reactivity between the different substrates at the interface shows a variation in the contributions of both reaction pathways, associative and dissociative, to the whole reaction mechanism. The confined media shift the point where the mechanism changes from an associative to a dissociative pathway, far away from the turning point in water. Furthermore, the change in mechanism can be modulated by modification of the microemulsion composition.

A systematic study on the solvolysis reaction of substituted benzoyl chlorides in the presence of zwitterionic vesicles of dipalmitoyl phosphatidylcholine (DPPC) has been performed. Size, shape, surface charge, and polarity of the interface of the vesicular aggregates were determined using various techniques. The application of the pseudophase formalism allowed us to obtain the thermodynamic and kinetic coefficients characteristic of the reaction. The effects of vesicular aggregates on the solvolysis of benzoyl chlorides, which are known to be sensitive to the physical properties of the medium, depend on the nature of the substrate. For benzoyl chlorides with electron-donating groups, which react predominantly through a dissociative mechanism which is strongly affected by medium properties, the rate constant decreases as the vesicle concentration increases. On the other hand, for benzoyl chlorides with electron-withdrawing groups, which react mainly via an associative pathway, DPPC vesicles catalyze the solvolysis reaction.

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Trends in ecosystem variables of the Eastern North Atlantic shelf near the Iberian Peninsula were analysed in relation to regional climate and oceanographic variability. In addition, detailed changes in oceanographic properties (surface temperature, upwelling and poleward current activity) and biological components (plankton and pelagic consumers) in the period 1989-2005 were compared with the main trends and multidecadal periods observed in time series dating back to 1950. In contrast to previous studies, the North Atlantic Oscillation did not appear as the main influence in the climate of the North Iberian region, while East-West and subtropical gradients were the dominant modes. Climatic oscillations at decadal scales were paralleled by similar oscillations in oceanographic and biological variables, but the latter appeared weakly related to climate. Time- lags of up to 5 years in the biological response may partly explain these relationships. The main planktivorous fish species (sardine and anchovy) alternate in periods of 10-15 years of relative dominance, in synchrony with equivalent species around the world. In contrast, plankton cycles appear greatly modified after 1990 in coincidence with shifts in climatic and oceanographic variables. Subregional variability indicated divergent trends in biological variables, particularly the zooplankton increase off A Coruña and the decrease in the Bay of Biscay since 1990. Such divergences are related to direct and indirect effects of global changes in this transitional upwelling region.

Objetivos: La perforación espontánea de una cistoplastia es un problema grave y potencialmente fatal, si no se diagnostica y se trata a tiempo. Se pretende: 1) buscar una prevención analizando los factores de riesgo, 2) identificar los principales datos de sospecha diagnóstica y 3) valorar el resultado de los tratamientos realizados. Material y Método: De 30 pacientes pediátricos con cistoplastia, 5 presentaron 8 perforaciones (16,6%). Se revisan los diversos factores influyentes, la clínica, los tratamientos y la evolución. Resultados: El tiempo medio transcurrido entre la cistoplastia y la perforación fue 8,2 años. Los principales factores de riesgo han sido una resistencia uretral que permitía continencia, y una insuficiente realización temporal del sondaje intermitente (SI). En los 8 episodios hubo dolor y distensión abdominal. La ecografía mostró líquido libre intraperitoneal en 5, múltiples quistes peritoneales en 1, e imagen sugestiva de plastrón apendicular en otro. La cistografía sólo mostró paso de contraste a la cavidad peritoneal en 3. El tratamiento inicial fue conservador, sin cirugía, en los 7 episodios diagnosticados preoperatoriamente, siendo la evolución favorable en 3 (42,8%); los otros 4 necesitaron tratamiento quirúrgico, con buena evolución en todos. De los 5 pacientes, 2 (40%) presentaron 3 recidivas en un tiempo medio de 5 años. La supervivencia es del 100 %. Conclusiones: El 16,6% de los pacientes con cistoplastia de esta serie, ha tenido uno o más episodios de perforación vesical espontánea. Los factores de riesgo más significativos son una resistencia uretral alta y la inadecuada realización del SI. Los pacientes con cistoplastia y sus familias deben conocer esta complicación, sus factores de riesgo y sus síntomas, para prevenirla o facilitar un diagnóstico precoz. Objective: The spontaneous cystoplasty perforation is a serious and potentially fatal problem if a delay in diagnosis and treatment occurs. We pretend: 1) to look for prevention analyzing the risk factors, 2) to identify the main data of diagnostic suspicion and 3) to evaluate the result of the treatments done. Material and Methods: Out of 30 children with cystoplasty 5 of them have presented 8 perforations (16,6%). Several influential factors, the symptoms, the treatments and the evolution are reviewed. Results: The average time between cystoplasty and the perforation was 8,2 years. A urethral resistance that allows continence, and an insufficient intermittent catheterization, have been the main risk factors. In the 8 episodes there were abdominal pain and distension. The ultrasonography showed intraperitoneal extravasation in 5 episodes, multiple peritoneal cysts in one, and suggestive image of appendicular plastron in another one. The cystography showed intraperitoneal extravasation only in 3 cases. The initial management was conservative in the 7 episodes diagnosed before surgery, and 3 had a good evolution (42,8%); the other 4 needed surgery with good evolution in all cases. Two of 5 patients (40%) presented 3 relapses in an average time of 5 years. The survival is 100%. Conclusions: 16,6% of patients with cystoplasty of this series had one or more episodes of spontaneous bladder perforation. The more significant risk factors are a high urethral resistance and an inadequate intermittent catheterization. The patients with cystoplasty, and their families, must know this complication, their risk factors and symptoms to prevent it, or to facilitate an early diagnosis.

The research survey PELACUS started at the 80s, particularly since 1983, and from 1986 onwards is a spring survey. Although it changed its name from time to time it has always been the northern Spanish acoustic research survey. Its main aim is the assessment of pelagic resources by acoustics tools across the northwest and northern Spanish waters. This survey is mainly targeted at sardine, although other pelagic resources are also taken into account, such as horse mackerel, mackerel and anchovy. The sampling area comprises the northern part of Portugal (ICES area IXa Central North), in the vicinity of Porto and extends to the southern Atlantic French waters (ICES area VIIIb), in the vicinity of Arcachon. Depths are from 30 to 200 m. The acoustic device is an echosounder EK-500, working at frequencies of 12, 38 and 120 KHz. This echosounder was replaced in 2005 by a new echosounder EK-60, working at frequencies of 18, 38, 70 and 120 KHz. Fish samples were collected by a pelagic trawling gear, with 24 m of vertical opening. An auxiliary purse-seiner is also chartered to help in shoal identification in coastal waters. This fishery boat is mainly used when the research vessel cannot fish because of the bathymetry, particularly in the Rias Bajas area, in Galicia. The presence of anchovy was rather occasional in PELACUS and no assessment is routinely produced because of the poor presence of this species on fishing samples as well as echograms. Also it has to be considered that this survey is mostly targeted to sardine and both ICES WGMHSA Report 2006 611 the distribution area and the main season of abundance of anchovy are not totally covered by this survey. Hence the research surveys PELACUS are considered NOT GOOD INDICATORS on anchovy distribution and abundance and conclusions regarding anchovy from this survey should be taken with caution.

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The natural abundance of stable nitrogen isotopes (δ15N) in sardine (Sardina pilchardus) and plankton was determined from samples collected between 1998 and 2003 in the northwestern shelf of the Iberian Peninsula with the purpose of studying the variability in the trophic position of sardine. Sardines were grouped in three size-length classes (small: < 16 cm; medium: 16-20 cm; large: > 20 cm). Plankton samples were size-fractionated between ca. 0.7 and 2000 μm of individual length. The plankton at the base of the pelagic food web in the western shelf region (Galicia) was more enriched in δ15N than plankton in the northern and eastern region (Mar Cantábrico), likely because of upwelling. Variability in δ15N in sardine was related both to changes in feeding strategies during growth and to the mobility of size classes between adjacent shelf regions. Large sardines showed regional differences in δ15N similar to those of small plankton, suggesting that old specimens remained for long periods in the same region. In contrast, small and medium-sized sardines have similar δ15N values in all regions. We hypothesize that interannual differences in δ15N of sardine are caused mainly by variations in the mobility of large size classes, as the isotopic signature of the small sardines was relatively less variable and suggests low variability in the plankton food web. In turn, such variations would be related to changes in the size of the sardine population in the north Iberian shelf.

The recent failure of sardine catches off Galicia (NW Spain), an area where landings reached up to 100 thousand tonnes only a few years ago, may be explained by two possible hypotheses. The "depletion" hypothesis states that diminishing sardine catches were due to a decrease in stock biomass resulting from a combination of reduced recruitment and increased fishing mortality. The "change in distribution" hypothesis states that catch failure was due to a change in the distribution of the stock owing to environmental changes. Available information, based on direct observations from acoustic and ichthyplankton surveys and the fishery, was analysed. When the stock size is high, the spawning area of the sardine extends offshore in the Cantabrian Sea, and spreads along the continental shelf off northern Portugal. Moreover, adult fish undertake feeding migration towards Galician waters. This spawning behaviour results in a recruitment located mainly off Portugal. Low stock size causes a shrinkage in the distribution area throughout coastal waters and in the Cantabrian Sea, reaching the inner part of the Bay of Biscay. This process also affects the migration range and favours a higher retention in coastal waters of the early life stages (from eggs to recruits), which remain primarily in the same area where they were hatched. The lack of sardine in Galicia may be explained by a depletion process which affects both the feeding migration of adult fish and the recruitment occurrence off southern Galicia. This paper also analyses the dynamics of this stock in the context of a metapopulation. Taking this concept into consideration, we also examined the influence of the dynamics of each sub-population and the environmental conditions that might affect the success of the recruitment., SI