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Extreme storms can trigger abrupt and often lasting changes in ecosystems by affecting foundational (habitat-forming) species. While the frequency and intensity of extreme events are projected to increase under climate change, its impacts on seagrass ecosystems remain poorly documented. In January 2020, the Spanish Mediterranean coast was hit by Storm Gloria, one of the most devastating recent climate events in terms of intensity and duration. We conducted rapid surveys of 42 Posidonia oceanica meadows across the region to evaluate the extent and type of impact (burial, unburial and uprooting). We investigated the significance of oceanographic (wave impact model), geomorphological (latitude, depth, exposure), and structural (patchiness) factors in predicting impact extent and intensity. The predominant impact of Storm Gloria was shoot unburial. More than half of the surveyed sites revealed recent unburial, with up to 40 cm of sediment removed, affecting over 50 % of the meadow. Burial, although less extensive, was still significant, with 10-80 % of meadow cover being buried under 7 cm of sediment, which is considered a survival threshold for P. oceanica. In addition, we observed evident signs of recently dead matte in some meadows and large amounts of detached drifting shoots on the sea bottom or accumulated as debris on the beaches. Crucially, exposed and patchy meadows were much more vulnerable to the overall impact than sheltered or continuous meadows. Given how slow P. oceanica is able to recover after disturbances, we state that it could take from decades to centuries for it to recoup its losses. Seagrass ecosystems play a vital role as coastal ecological infrastructure. Protecting vulnerable meadows from anthropogenic fragmentation is crucial for ensuring the resilience of these ecosystems in the face of the climate crisis.

Extreme storms can trigger abrupt and often lasting changes in ecosystems by affecting foundational (habitat-forming) species. While the frequency and intensity of extreme events are projected to increase under climate change, its impacts on seagrass ecosystems remain poorly documented. In January 2020, the Spanish Mediterranean coast was hit by Storm Gloria, one of the most devastating recent climate events in terms of intensity and duration. We conducted rapid surveys of 42 Posidonia oceanica meadows across the region to evaluate the extent and type of impact (burial, unburial and uprooting). We investigated the significance of oceanographic (wave impact model), geomorphological (latitude, depth, exposure), and structural (patchiness) factors in predicting impact extent and intensity. The predominant impact of Storm Gloria was shoot unburial. More than half of the surveyed sites revealed recent unburial, with up to 40 cm of sediment removed, affecting over 50 % of the meadow. Burial, although less extensive, was still significant, with 10–80 % of meadow cover being buried under 7 cm of sediment, which is considered a survival threshold for P. oceanica. In addition, we observed evident signs of recently dead matte in some meadows and large amounts of detached drifting shoots on the sea bottom or accumulated as debris on the beaches. Crucially, exposed and patchy meadows were much more vulnerable to the overall impact than sheltered or continuous meadows. Given how slow P. oceanica is able to recover after disturbances, we state that it could take from decades to centuries for it to recoup its losses. Seagrass ecosystems play a vital role as coastal ecological infrastructure. Protecting vulnerable meadows from anthropogenic fragmentation is crucial for ensuring the resilience of these ecosystems in the face of the climate crisis.

The overturning streamfunction is a widely used metric to monitor ocean circulation changes in the North Atlantic Ocean. Analogously, it is known that an overturning circulation develops in the Mediterranean Sea, although substantially weaker and smaller than in the Atlantic. In this work we use monthly mean fields from a high-resolution ocean reanalysis (1/16°×1/16°) to explore seasonal and interannual variability of Mediterranean Sea overturning circulation in depth and water mass parameter spaces (potential density, potential temperature, salinity) from 1987 to 2018 (both included). Results show a clear single zonal clockwise transport cell in all three spaces that extends from the Strait of Gibraltar to the Levantine Basin, in which water masses tend to densify as they move eastward. This densification is mainly controlled by salinity in the Eastern Mediterranean basin (EMED), while in the Western Mediterranean (WMED) both salinity and potential temperature variations should be taken into account. In contrast, the meridional overturning transport, much more complex, is able to better capture smaller-scale variations since it responds faster to perturbations in the circulation. Seasonal variations in overturning transport are reflected in the size and strength of overturning cells in all spaces, being cells remarkably narrower in winter than in summer. Regarding interannual changes, we show that the meridional overturning transport in density space is significantly correlated with the North Atlantic Oscillation, the Mediterranean Oscillation Index and the Scandinavian pattern during wintertime in the WMED, and with the Eastern Atlantic and the East Atlantic–Western Russian in the EMED. The overturning metric in density space captures well the Eastern Mediterranean Transient, that occurred during years 1992–1996. Finally, we explore the usefulness of overturning metric to detect and track water mass changes associated to shorter scale events, using as example the

While the prioritisation of scarce resources for climate adaptation is becoming a priority for low and middle income countries, the climate service literature addressing adaptation prioritisation decisions is scarce. This paper contributes to filling this gap by presenting a co-creation process carried out in the Maldives among representatives of government, civil society and researchers. Together, we identified the need to improve a ranking method currently used by the Maldivian government to prioritise islands for investments in erosion prevention. As a solution we developed a layered index. The first layer of this index captures the objective dimension of the problem through an erosion hazard subindex, using the three variables wave energy, reef health and reef flat minimum width. The second layer captures the normative dimension through a multi-criteria analysis using the erosion hazard subindex as one criterion next to other stakeholder selected criteria such as critical infrastructure, economic activity, per capita income and the potential to house additional people that resettle from riskier places as sea-level rise progresses. Results of this new ranking method show that socioeconomic criteria were considered more important by the stakeholders than the biophysical criterion of erosion hazard. Among the top-ranked islands are many regional centres but also less populous islands that have a large potential to house additional people. Lessons learnt from the co-creation process highlight the importance of assembling interdisciplinarity teams, fostering mutual learning among project participants, and designing research projects that do not prescribe upfront the exact problems to be addressed and methods to be applied.

This chapter introduces the concept of mean sea level and discusses its variability at low frequency time scales (from monthly periods to multidecadal oscillations to millennial changes) in the Mediterranean Sea. It first describes the main techniques for measuring sea level, including instrumental in situ observations from tide gauges and remote observations from altimeters on board of satellites, as well as sea level proxies that are used to reconstruct sea level at millennial time scales. Ancillary geodetic measurements are also described, as these are relevant for coastal monitoring and sea level impacts. Secondly, the chapter focuses on the past evolution of Mediterranean sea level, starting with Holocene changes (ca. 10 kyrs back in time), followed by decadal to centennial sea level trends since the late 19th century, a period coinciding with the instrumental era. Finally, future mean sea level projections in the Mediterranean Sea are provided for the present century and for two climate change scenarios.

Tide gauge data and information from tide, surge and ocean models have been used to calculate and validate the Gumbel scale parameters of extreme sea level distributions along the world coastline. The inclusion of ocean model information is found to result in significantly improved correspondence between observed and modelled scale parameters to that obtained using tide and surge model information alone. The scale parameters so obtained are shown to be consistent with findings reported previously, such as in assessments of the Intergovernmental Panel on Climate Change. However, the considerably improved provision of scale parameters along the coast means that coastal planners, and others concerned with impacts of sea level rise, can now undertake more complete investigations of the likely increase in sea level exceedance frequencies. In addition, coastal engineers will have access to more reliable estimates of the ‘sea level allowances’ needed to design defences for protecting coastal populations.

[Abstract] Heart failure is a complex entity, with high morbidity and mortality. The clinical course and outcome are uncertain and difficult to predict. This document, instigated by the Heart Failure and Geriatric Cardiology Working Groups of the Spanish Society of Cardiology, addresses various aspects related to palliative care, where most cardiovascular disease will eventually converge. The document also establishes a consensus and a series of recommendations with the aim of recognizing and understanding the need to implement and progressively apply palliative care throughout the course of the disease, not only in the advanced stages, thus improving the care provided and quality of life. The purpose is to improve and adapt treatment to the needs and wishes of each patient, who must have adequate information and participate in decision-making., [Resumen] La insuficiencia cardiaca es una entidad compleja, que conlleva elevada morbilidad y mortalidad y cuyo curso y evolución son inciertos y difíciles de predecir. Este trabajo, impulsado por las Secciones de Insuficiencia Cardiaca y Cardiología Geriátrica de la Sociedad Española de Cardiología, aborda los diferentes aspectos relacionados con los cuidados paliativos en el campo de la insuficiencia cardiaca, vía final común de la mayoría de las enfermedades cardiovasculares. También establece un consenso y una serie de recomendaciones con el objetivo de reconocer y comprender la necesidad de implementar y aplicar, de modo progresivo, este tipo de cuidados a lo largo del curso de la enfermedad, y no únicamente en sus estadios avanzados, para mejorar la atención que reciben los pacientes y su calidad de vida. La finalidad es mejorar y adecuar los tratamientos a las necesidades y los deseos de cada paciente, que debe contar con información adecuada y ser partícipe de la toma de decisiones.

In spite of the recent advances and the current perspectives of satellite radar altimetry to reach the coastline and monitor coastal sea level changes, this space-borne technology remains geocentric by essence. In contrast, the quantity that matters for coastal management and society is relative sea level. That is, the sea level relative to the land, as measured by conventional tide gauges. However, two important issues are associated with the use of tide gauges. First, supplemental information is required to separate vertical land motion from ocean climate signals in tide gauge records, and hence to understand the causes of future coastal sea level changes and their relative importance. This can be provided by space-borne geodetic techniques, for instance installing a permanent Global Positioning System (GPS) antenna at the tide gauge. Second, vertical land motion can show local spatial patterns, which limits the spatial validity of the point-wise information at the GPS station. Using Interferometry Synthetic Aperture Radar (InSAR) and high-precision GPS data, the above-mentioned limitations were addressed in the case study of Brest (France). Our findings show that, over the past decades, Brest and its surroundings are overall stable, in agreement with the geological setting, except for the embankment areas of the commercial and military harbours. The GPS-calibrated InSAR results were then further combined with geocentric satellite radar altimetry data to obtain relative sea level trends along the Brest coastline with an unprecedented high-spatial resolution of 200 m. Our approach is applicable beyond the case study of Brest, especially in coastal areas where tide gauge data are not available, provided satellite data are.

A dynamical wind-wave climate simulation covering the North Atlantic Ocean and spanning the whole 21st century under the A1B scenario has been compared with a set of statistical projections using atmospheric variables or large scale climate indices as predictors. As a first step, the performance of all statistical models has been evaluated for the present-day climate; namely they have been compared with a dynamical wind-wave hindcast in terms of winter Significant Wave Height (SWH) trends and variance as well as with altimetry data. For the projections, it has been found that statistical models that use wind speed as independent variable predictor are able to capture a larger fraction of the winter SWH inter-annual variability (68% on average) and of the long term changes projected by the dynamical simulation. Conversely, regression models using climate indices, sea level pressure and/or pressure gradient as predictors, account for a smaller SWH variance (from 2.8% to 33%) and do not reproduce the dynamically projected long term trends over the North Atlantic. Investigating the wind-sea and swell components separately, we have found that the combination of two regression models, one for wind-sea waves and another one for the swell component, can improve significantly the wave field projections obtained from single regression models over the North Atlantic.

The new gridded Mediterranean sea level anomaly product recently released by AVISO (DT14) is evaluated and compared with the earlier version (DT10) at which it is aimed to substitute. Differences between the two products are found along coastal regions, where the new version captures more variability (up to 10% more) and trends locally differ by up to 1 mm/yr for the altimetric period. Coastal tide gauge observations have therefore been used as the basis for quantifying changes in DT14. Correlation and variance reduction in available monthly tide gauge time series are improved in more than 80% of the selected sites by up to 0.2 and 5 cm2, respectively. This resulted in an overall higher skill to recover coastal low frequency (with periods larger than a few months) sea level signals. Results for higher/lower order percentiles were also explored and showed different performances depending on the site, although with a slight overall improvement. A comparison with tide gauges on a daily basis using wavelet analysis reveals that altimetry gridded products are not capable of recovering higher frequency (a few days) coastal sea level signals despite some advances have been achieved thanks to the daily temporal sampling of DT14

We estimated the vertical land movement rates at tide gauge stations along the Gulf of Mexico (GOM) coasts. A novel approach suggested by Kuo et al. (2004, 2008) for combining satellite altimetry and tide gauge data was applied. The obtained vertical land motion rates were compared with the GPS vertical velocities measured at Galveston, Grand Isle, Dauphin Island, Pensacola and Key West stations. The estimated vertical rates range from slow subsidence in the South of Florida and Veracruz to high subsidence rates in Texas and Louisiana where some of the tide gauges subside at the rate of up to 7 mm/yr. A small but noticeable uplift in the NE of the Gulf was detected at Cedar Key and Apalachicola and a very low subsidence at Pensacola tide gauge. We suppose there are some local tectonic processes which contribute significantly to the land movement at these stations. Comparison with the post-glacial rebound model ICE5G-VM2 predictions shows that the drivers of the subsidence on the GOM shelf are of local nature. The resulted absolute sea level rise along the GOM coast was estimated to be about 2.0±0.4 mm/yr.

© 2014 Elsevier B.V. The spatial and temporal scales of variability of ocean bottom pressure (Pb) in the Mediterranean Sea are characterized and their relationship with sea level was assessed using a high resolution eddy-permitting regional ocean model spanning the period 1999-2011. It was found that rapid (periods of a few days) bottom pressure fluctuations are coherent with sea level and are decoupled between the eastern and western basins as a result of topographic constraints. In the longer periods, steric processes gained relevance away from the coast and partially broke the coherence between sea level and Pb, especially on the western basin. Results confirm that sea level changes are predominantly barotropic over most of the basin and at all time scales, except for the annual cycle. Along the coasts sea level fluctuations reflected local steric processes taking place in their vicinity. This effect was stronger on the western basin, whereas the coasts of the Eastern Mediterranean arise as the most suitable proxies for basin wide long term (>60days) mean sea level (or ocean bottom pressure) changes at non-seasonal periods.

The relationships of Mediterranean sea level, its atmospherically driven and thermosteric components with the large scale atmospheric modes over the North Atlantic and Europe are explored and quantified. The modes considered are the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the Scandinavian pattern (SCAN) and the East Atlantic/Western Russian (EA/WR). The influence of each mode changes between winter and summer. During winter the NAO is the major mode impacting winter Mediterranean sea level (accounting for 83% of the variance) with SCAN being the second (56%) mode in importance. Both NAO and SCAN effects are partly due to direct atmospheric forcing of sea level through wind and pressure changes. However NAO and SCAN are correlated with each other during winter and they explain the same part of variability. The EA/WR also affects the atmospheric sea level component in winter (13%), acting through atmospheric pressure patterns. In winter, the thermosteric contribution is correlated with the SCAN in parts of the Eastern Mediterranean (9%). The rate of change of the thermosteric component in winter is correlated with the EA (24%). During the summer season, the sea level variance is much reduced and the impact of the large scale modes is in most parts of the Mediterranean Sea non-significant

In coastal low-lying urban areas, vertical ground motions can significantly exacerbate the hazards related to sea-level rise. However, their spatial extent, their temporal evolution, and even sometimes their existence are often poorly known. This study aims to monitor variable urban ground motion (uplift and subsidence) from 1993 to 2010 in the metropolitan area of Manila, Philippines. Because high subsidence rates have been reported in this city in previous studies, conventional Differential SAR Interferometry (DInSAR) was applied with an adapted stacking procedure to the archive of ERS and Envisat satellite images to produce surface deformation-velocity maps for different periods. The results showed that the city is locally affected by vertical ground motions on the order of 15. cm/yr. Moreover, the spatio-temporal evolution of the ground-motion phenomena is highly nonlinear. These results are in good agreement with previous studies focused on groundwater use in Manila and in the Marikina Fault Valley, suggesting a plausible interpretation of the processes causing surface motion. Incidentally, the ground motions are affecting the locations of several geodetic instruments, including a tide gauge with sea-level records starting in 1902, two permanent GPS (Global Positioning System) stations, and a DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) station. A major implication of those large and locally variable ground motions is that they impede the use of the nearby GPS and DORIS data to correct the tide-gauge records and to derive robust sea-level trends associated with climate change. © 2013 Elsevier Inc.

Wave climate in the Western Mediterranean is presented through the calibration of an update wind wave hindcast spanning the period 1958-2008. The hindcast was obtained with the WAM model (spatial resolution of 1/6°) forced with wind fields from the atmospheric model ARPERA. Significant wave heights (SWH) provided by the hindcast were calibrated using buoy observations with the aim of improving the characterization of the wave climate over the region. The methodology is based on a spatial calibration of the statistical distribution of SWH performed through a non-linear transformation of the Empirical Orthogonal Functions of the modeled data that minimizes the differences with observations. This allows the calibration to be implemented not only at buoy locations, but also all over the model domain. The resulting fields were validated against satellite altimetry observations, showing an average reduction of about 76% in the bias and of about 10% in the root mean squared differences with respect to observations. © 2013 Elsevier B.V.

This paper documents the present climate and future climate projections of sea-level variability (SLV) induced by atmospheric pressure and wind for period bands ranging from 1 to 100. days in the Mediterranean Sea. The results are based on output from a regional barotropic numerical ocean model. Present climate SLV was simulated using air pressure and wind fields from a dynamical downscaling of the ERA40 reanalysis for 1958-2008 (hindcast) and validated with long-term tide gauge records. Climate projections for the 21st century were forced with output from the atmospheric ARPEGE model using scenarios B1, A1B and A2. Additionally, we performed a control simulation forced by observed SSTs, GHGs and aerosol concentrations for the period 1950-2000. SLV has been assessed over three different period bands (1-3, 3-10 and 10-100. days) that were obtained by applying digital band-pass filtering procedures to both the present day and climate projections. Of the three time periods, the 1-3-day SLV had the worst comparability between the hindcast and the observations. We found that most of the SLV trends were insignificant in the present climate but were negative in the projections over all of the periods, especially for the medium- (A1B) and high-emission (A2) scenarios. Projections of 3-10- and 10-100-day extreme SLV, estimated from high-order percentiles, indicate increases in extreme SLV events versus the average. This result does not apply to the 1-3-day extreme SLV. The largest negative SLV trends were projected for autumn and for the 1-3-day period band, except for the low-emission (B1) scenario. However, the 1-3-day period band contributed less than 12% to the overall SLV, while the largest variance (55-75%) was present in the 10-100-day period band, indicating the importance of correct simulation of planetary-scale atmospheric processes with long temporal scales for the reliability of the climate projections. © 2012 Elsevier B.V..

The contributing factors to regional sea level variability have been explored for the period 2004-2008 based on altimetry observations, hydrographic data and GRACE measurements. The regional averaged annual cycle of the mass contribution to sea level is shown to be highly unsteady. When compared with steric-corrected altimetry, both signals are coherent, though in some regions the coherence analysis is limited by the use of interpolated hydrographic data and in the equatorial regions it is limited by the low signal-to-noise ratio of GRACE data. The closure of regional sea level budgets depends mainly on the GIA correction chosen. A reconstructed global sea level field (with the atmospheric signal eliminated) spanning the second half of the 20th century together with historical hydrographic observations are used to infer the regional mass contribution to sea level rise for the last decades. Results indicate that mass addition from continental ice is the major contributor to regional mean sea level rise for the last decades. In addition, the spatial patterns of mass rates of change point at Greenland as the main source of fresh water input. © 2011 Elsevier B.V.

Sea level trends in the Mediterranean Sea and their forcing parameters are explored. Multi-decadal trends from available tide gauge records are estimated together with the contribution of the oceanic (steric and mass variations) and atmospheric (pressure and wind) changes as well as land movements (including GIA). Each forcing factor is considered as an independent process creating its own signal on a tide gauge, and subject to uncertainties of measurement, deduction or interpretation of proxy data for that factor. The paper is focused on the uncertainty of the estimate of each forcing factor, including the estimate of the eustatic part affecting the Mediterranean Sea, obtained by subtracting GIA and land movements obtained from geomorphological and archaeological data at the tide gauge stations. © 2010 Elsevier B.V.

Changes in storm surges in the Mediterranean Sea and the Atlantic Iberian coasts during the 21st century are explored based on the outputs of a numerical barotropic regional model. Three different climate scenarios (A2, A1B and B1) for the period 2000-2099 together with a control run for 1950-2000 have been simulated forced by greenhouse gases concentrations. A hindcast run for the 20th century (1958-2001) forced with a dynamical downscaling of ERA40 reanalysis has also been performed. Comparisons between hindcast and control run show consistency on their average statistics and their spatial distribution in terms of extreme events. Results for the 21st century reveal that storm surges frequency and magnitude decrease. Changes reach 50% in the number of events and up to 8. cm in the 50-year return levels. The analysis shows a progressive decrease in the return levels not fully explained by a negative trend in the mean atmospherically-induced sea level and a linear dependence with winter NAO. Likewise, negative events show the opposite behavior, with an increase in their frequency and magnitude although smaller than for positive surges. © 2011 Elsevier B.V.

The mass contribution to Mediterranean Sea level variability is estimated from steric-corrected altimetry and from GRACE observations for the period August 2002 to December 2006. The two signals are highly correlated (0.8) and display coherent trends, provided that a proper spatial averaging kernel is used to extract the gravity signal from GRACE coefficients (the same filter is applied to all fields in order to obtain consistent and comparable signals). The good agreement between GRACE observations and steric-corrected altimetry supports the quantification of the long-term mass contribution in terms of non-steric sea level in the Mediterranean. For the past decades, total sea level fields are reconstructed using a reduced-space optimal interpolation of altimetry and tide gauge data. The steric component is evaluated from hydrographic observations available for the same period for the upper 700 m. The errors associated with total sea level and the steric component are evaluated in order to obtain the uncertainty of non-steric sea level. Results indicate that the mass content of the Mediterranean basin has increased at a rate of 0.8 ± 0.1 mm/yr for the period 1948–2000. When the effect of the atmospheric pressure is removed, the trend of the mass component increases up to 1.2 ± 0.2 mm/yr.

Sealevelextremes and their temporal variability have been explored based on the hourly measurements at Marseille tide gauge for the period 1885–2008. A careful quality check has first been applied to the observations to ensure consistency of the record by eliminating outliers and datum shifts. Yearly percentiles have been used to investigate long-term trends of extremes revealing that secular variations in extremes are linked to mean sealevel changes. The associated decadal changes show discrepancies between mean sealevel trend and extreme fluctuations, due to the influence of the atmospheric forcing. A local regression model based on the generalized Pareto distribution has been applied to derive trends in return levels. The 50-years return levels reach values between 80 and 120 cm. The most significant changes in return levels are characterized by an increase since the 1970s.

Two Mediterranean sea level distributions spanning the last decades are examined. The first one is a reconstruction of sea level obtained by a reduced-space optimal interpolation applied to tide gauge and altimetry data. The second distribution is obtained from a 3D (baroclinic) regional circulation model. None of the two representations includes the mechanical atmospheric forcing. Results are presented for two different periods: 1993-2000 (for which altimetry data are available) and 1961-2000 (the longest period common to both distributions). The first period is examined as a test period for the model, since the reconstruction is very similar to altimetry observations. The modelled sea level is in fair agreement with the reconstruction in the Western Mediterranean and in the Aegean Sea (except in the early nineties), but in the Ionian Sea the model departs from observations. For the whole period 1961-2000 the main feature is a marked positive trend in the Ionian Sea (up to 1.8 mm yr- 1), observed both in the reconstruction and in the model. Also the distribution of positive trends in the Western Mediterranean (mean value of 1.1 mm yr- 1) and the smaller trends in the Aegean Sea (0.5 mm yr- 1) are similar in the reconstruction and in the model, despite the first implicitly accounts for sea level variations due to remote sources such as ice melting and the second does not. The interannual sea level variability associated with key regional events such as the Eastern Mediterranean Transient is apparently captured by the reconstruction but not by the model (at least in its present configuration). Hence, the reconstruction can be envisaged as a useful tool to validate further long-term numerical simulations in the region. © 2009 Elsevier B.V. All rights reserved.

The aim of the present paper is to study the relationships between some climatic indices and parental stock, recruitment and accessibility to trawl fishery of hake (Merluccius merluccius) and red shrimp (Aristeus antennatus) off Balearic Islands (western Mediterranean). Available annual catch per unit effort, recruitment and spawning stock biomass have been used as biological data. As environmental data, the meso-scale IDEA index and the large-scale North Atlantic Oscillation (NAO) and Mediterranean Oscillation (MO) indices have been used. To analyze possible links between these indices with the population dynamics of demersal resources, two non-linear approaches have been applied: (i) stock-recruitment relationships from Ricker and Beverton-Holt models, by sequentially incorporating environment factors; (ii) generalized additive modelling, both classical general and threshold non-additive models were considered. The latter simulate an abrupt change in explicative variables across different phases (time periods or climatic index values). The results have shown that two oceanographic scenarios around the Balearic Islands, associated with macro and meso-scale climate regimes, can influence the population dynamics of hake and red shrimp. This is especially true for recruitment, which seems to be enhanced during low NAO and IDEA indices periods. During these periods, colder-than-normal winters generate high amounts of cold Western Mediterranean Intermediate Waters (WIW) in the Gulf of Lions, which flow southwards and reach the Balearic Islands channels in spring, increasing the productivity in the area. This oceanographic scenario could also be favourable to the distribution of hake on the fishing grounds where the trawl fleet targets this species, increasing its accessibility to the fishery. Both spawning stock and abundance of red shrimp seems to be also enhanced by high MO index periods, which could reflect the increased presence of the saline and warm Levantine Inte

This paper describes the hydrographic conditions observed during six surveys carried out during 2003 and 2004, in the framework of the >IDEA Project> (acronym for >Influence of oceanographic structure and dynamics on demersal populations in waters of the Balearic Islands>). The surveys were developed on the shelf and slope of Mallorca Island, in particular in two fishing grounds at the north and south of the Mallorca channel. Periodic movements of the fishing fleet between these two areas have been regularly reported, suggesting a seasonal variability of the resources which could be in turn associated with the hydrodynamic variability. With this motivation, water masses affecting these grounds have been identified and their seasonal variability has been studied. Different oceanographic and environmental conditions have been found between the two fishing grounds. These differences are related to the presence of mesoscale structures, associated with the Western Mediterranean Intermediate Water (WIW) at the north of the Ibiza channel and big gyres detached from the Algerian Current. The former has been shown to have influence on the regional oceanic circulation and the latter could affect the progress of fresh Atlantic Water (AW) towards the channels and make possible the presence of high salinity values at intermediate waters at the south of Mallorca Island. Historical data from other oceanographic cruises carried out in the region are finally used to discuss the interannual variability of these mesoscale structures. © 2007 Elsevier B.V. All rights reserved.