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Instituto Español de Estudios Estratégicos

facilityMadrid, Madrid, Spain

Research output, citation impact, and the most-cited recent papers from Instituto Español de Estudios Estratégicos (Spain). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
503
Citations
16.7K
h-index
68
i10-index
332
Also known as
Instituto Español de Estudios Estratégicos

Top-cited papers from Instituto Español de Estudios Estratégicos

Do experts make mistakes? A comparison of human and machine identification of dinoflagellates
Phil Culverhouse, R. Williams, Beatriz Reguera, V. Herry +1 more
2003· Marine Ecology Progress Series271doi:10.3354/meps247017

The authors present evidence of the difficulties facing human taxonomists/ecologists in identifying marine dinoflagellates. This is especially important for work on harmful algal blooms in marine aquaculture. It is shown that it is difficult for people to categorise specimens from species with significant morphological variation, perhaps with morphologies overlapping with those of other species. Trained personnel can be expected to achieve 67 to 83% self-consistency and 43% consensus between people in an expert taxonomic labelling task. Experts who are routinely engaged in particular discriminations can return accuracies in the range of 84 to 95%. In general, neither human nor machine can be expected to give highly accurate or repeatable labelling of specimens. It is also shown that automation methods can perform as well as humans on these complex categorisations.

Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research
Paola Malanotte‐Rizzoli, Vincenzo Artale, G. L. Borzelli-Eusebi, S. Brenner +4 more
2014· Ocean science213doi:10.5194/os-10-281-2014

Abstract. This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop discussions, a number of unresolved issues were identified for the physical and biogeochemical properties of the Mediterranean Sea as a whole, i.e., comprising the Western and Eastern sub-basins. Over the successive two years, the related ideas were discussed among the group of scientists who participated in the workshop and who have contributed to the writing of this paper. Three major topics were identified, each of them being the object of a section divided into a number of different sub-sections, each addressing a specific physical, chemical or biological issue: 1. Assessment of basin-wide physical/biochemical properties, of their variability and interactions. 2. Relative importance of external forcing functions (wind stress, heat/moisture fluxes, forcing through straits) vs. internal variability. 3. Shelf/deep sea interactions and exchanges of physical/biogeochemical properties and how they affect the sub-basin circulation and property distribution. Furthermore, a number of unresolved scientific/methodological issues were also identified and are reported in each sub-section after a short discussion of the present knowledge. They represent the collegial consensus of the scientists contributing to the paper. Naturally, the unresolved issues presented here constitute the choice of the authors and therefore they may not be exhaustive and/or complete. The overall goal is to stimulate a broader interdisciplinary discussion among the scientists of the Mediterranean oceanographic community, leading to enhanced collaborative efforts and exciting future discoveries.

Mediterranean Outflow Mixing and Dynamics
James F. Price, Molly Baringer, Rolf G. Lueck, Gregory C. Johnson +4 more
1993· Science173doi:10.1126/science.259.5099.1277

The Mediterranean Sea produces a salty, dense outflow that is strongly modified by entrainment as it first begins to descend the continental slope in the eastern Gulf of Cadiz. The current accelerates to 1.3 meters per second, which raises the internal Froude number above 1, and is intensely turbulent through its full thickness. The outflow loses about half of its density anomaly and roughly doubles its volume transport as it entrains less saline North Atlantic Central water. Within 100 kilometers downstream, the current is turned by the Coriolis force until it flows nearly parallel to topography in a damped geostrophic balance. The mixed Mediterranean outflow continues westward, slowly descending the continental slope until it becomes neutrally buoyant in the thermocline where it becomes an important water mass.

Embedding Population Dynamics Models in Inference
S. T. Buckland, Ken B. Newman, Carmen Fernández, Len Thomas +3 more
2007114

Abstract. Increasing pressures on the environment are generating an ever-increasing need to manage animal and plant populations sustainably, and to protect and rebuild endangered populations. Effective management requires reliable mathematical models, so that the effects of management action can be predicted, and the uncertainty in these predictions quantified. These models must be able to predict the response of populations to anthropogenic change, while handling the major sources of uncertainty. We describe a simple “building block” approach to formulating discrete-time models. We show how to estimate the parameters of such models from time series of data, and how to quantify uncertainty in those estimates and in numbers of individuals of different types in populations, using computer-intensive Bayesian methods. We also discuss advantages and pitfalls of the approach, and give an example using the British grey seal population. Key words and phrases: Hidden process models, filtering, Kalman filter, matrix population models, Markov chain Monte Carlo, particle

Shallow slides and pockmark swarms in the Eivissa Channel, western Mediterranean Sea
Galderic Lastras, Miquel Canals, Roger Úrgeles, John E. Clark +1 more
2004· Sedimentology100doi:10.1111/j.1365-3091.2004.00654.x

Abstract Four slides, the Ana, Joan, Nuna and Jersi slides, have been imaged on the seafloor along the Balearic margin of the Eivissa Channel in the western Mediterranean. They have areas of up to 16 km 2 and occur in water depths ranging between 600 and 900 m. Volumes range from 0·14 to 0·4 km 3 . Their headwall scarps, internal architecture and associated deposits are characterized using a combination of swath bathymetry data and very high‐resolution seismic reflection profiles. In general, they show horseshoe‐shaped headwall scarps and distinct depositional lobes with positive relief. Internally, the slide bodies are mostly composed of transparent seismic facies. Chaotic facies are observed at the toe of some of the slides, and blocks of coherent stratified facies embedded in the slide deposit have also been identified. The reflection profiles demonstrate that the four slides share the same slip horizon, which corresponds to a distinctive continuous, high‐amplitude reflector. Furthermore, the geometry of the headwall scars of the Nuna and Ana slides reveals evidence of pockmarks, and fluid escape features are also present further upslope. This indicates a possible link between fluid escape features and destabilization of the upper sediment layers. In addition, these well‐characterized slides demonstrate the pitfalls associated with calculating the volume of the slide masses using headwall scarp heights and the assumed preslide seafloor topography in the absence of seismic data. The internal structure also demonstrates that transport distances within the slides are generally low and poorly characterized by headwall scarp to slide toe lengths.

Energy balance, gonad development and biochemical composition in the clam Ruditapes decussatus
A. Pérez Camacho, Marina Delgado, MJ Fernández-Reiriz, Uxío Labarta
2003· Marine Ecology Progress Series95doi:10.3354/meps258133

This study evaluates the influence of different states of energy balance, positive and negative, on the accumulation and utilisation of energy reserves during the period of gonad development in the clam Ruditapes decussatus (L.). Our results show a clear sexual differentiation in the biochemical composition of the clams. The differences were associated with gonad development and were particularly evident in proteins and lipids. These findings imply that separation of the sexes for studying variations in the biochemical composition of sexually developed specimens is essential, and thus questions the results of previous studies in which both sexes were analysed simultaneously. Gonad development occurs under conditions of both positive and negative energy balance, and permits the development of a model of the utilisation of reserves during gonad development, which is closely linked to the clam’s energy balance. Under conditions of positive energy balance, the amount of food ingested provides sufficient energy for both metabolic consumption and the accumulation of reserves. The absolute value of all biochemical components increases, in particular for lipids in the case of female clams, with no evidence of consumption of glycogen and other carbohydrates or their conversion into lipid reserves. Conditions of negative energy balance lead to a moderate degree of organic weight loss in the clams. Glycogen and other carbohydrates are rapidly consumed, falling to almost a quarter of initial values, whilst protein and lipid levels remain constant in females. Lipid values decrease slightly in males. Finally, under situations of extreme nutritive stress (when energy reserves are scarce) there is a loss of all biochemical components in a specific order of priority. Most of the glycogen and other carbohydrates are consumed initially (a decrease of 61 and 74%, respectively), followed to a lesser extent by lipids in males (40%) and then proteins (between 20 and 25%). In females, there was no lipid loss until the majority of the carbohydrates and part of the proteins had been consumed, indicating that lipids constitute the reproductive reserve par excellence in this species.

Construction of an oceanic island: Insights from the El Hierro (Canary Islands) 2011-2012 submarine volcanic eruption
J. Rivera, Galderic Lastras, Miquel Canals, J. Acosta +4 more
2013· Geology79doi:10.1130/g33863.1

Eight consecutive swath bathymetry data sets were obtained to monitor the submarine eruption that occurred from 10 October 2011 to 5 March 2012 south of El Hierro Island in the Canary Islands. An increase in seismic activity since July 2011 preceded the onset of the eruption, which was marked by seismic tremor and stained waters. The first bathymetry, 15 d after the eruption started, depicts a cone topping at 205 m depth, growing on a preexisting valley. Recurrent mapping shows changes in the morphology and depth of the cone, allowing us to identify collapses and calculate eruptive volumes and rates, which peaked at 12.7 × 106 m3 d-1 of non-dense rock equivalent (NDRE) on 29-30 October. The final cone consists of at least four vents along a north-northwest-south-southeast lineation, with the shallowest summit at 89 m depth. The total accumulated volume was 329 × 106 NDRE m3, of which one-third formed the cone. Similar cones have been identified on the submerged flanks of the island, with volumes ranging from <50 × 106 to >1000 × 106 NDRE m3. As in many other volcanic islands, large-scale landslides play an important role in the evolution of El Hierro. A giant flank landslide (El Golfo, 13-134 ka, 150-180 km3) mobilized, in a single event, a volume equivalent to 450-550 eruptions of the size of the reported one, showing striking differences in the construction and destruction rates of the island. This study is relevant for future monitoring programs and geohazard assessment of new submarine eruptions.

Comparative study of gonadal development of Ruditapes philippinarum (Adams and Reeve) and Ruditapes decussatus (L.) (Mollusca: Bivalvia): Influence of temperature
Marina Delgado, A. Pérez-Camacho
2007· Scientia Marina73doi:10.3989/scimar.2007.71n3471

Laboratory experiments were used to study the influence of temperature on the reproductive behaviour of two species of clam, Ruditapes decussatus and Ruditapes philippinarum, during their adaptation to the temperature conditions of Galician coastal waters. In both species the rate of gonadal development was directly related to the increase in temperature. At 14°C the reproductive behaviour was similar, both species needing over 2 months to mature. At 18°C, the rate of gonadal development of R. philippinarum was greater than that of R. decussatus. Nevertheless, the results of this study confirm that both species have adapted perfectly to the temperature conditions of the Galician Rias, though certain differences between the reproductive behaviour of these species were detected. R. philippinarum accumulates oocytes prior to their partial or total emission, while in the case of R. decussatus gametes are liberated continuously. In the early phases of its development, the gonad of R. philippinarum is highly heterogeneous in nature, with up to 3 reproductive states being present at the same time, while in R. decussatus gonadal development is much more uniform. Another major difference concerns the phenomenon of reabsorption, common in R. philippinarum but very rare in R. decussatus. These characteristics may well result in a greater reproductive activity in R. philippinarum than in R. decussatus, and a longer reproduction period in the former. They may also represent a certain advantage for the adaptation of the foreign species (R. philippinarum) over the native species (R. decussatus) to the temperature conditions of the Galician Rias.

Monte Carlo Inference for State–Space Models of Wild Animal Populations
Ken B. Newman, Carmen Fernández, Len Thomas, S. T. Buckland
2008· Biometrics72doi:10.1111/j.1541-0420.2008.01073.x

SUMMARY: We compare two Monte Carlo (MC) procedures, sequential importance sampling (SIS) and Markov chain Monte Carlo (MCMC), for making Bayesian inferences about the unknown states and parameters of state-space models for animal populations. The procedures were applied to both simulated and real pup count data for the British grey seal metapopulation, as well as to simulated data for a Chinook salmon population. The MCMC implementation was based on tailor-made proposal distributions combined with analytical integration of some of the states and parameters. SIS was implemented in a more generic fashion. For the same computing time MCMC tended to yield posterior distributions with less MC variation across different runs of the algorithm than the SIS implementation with the exception in the seal model of some states and one of the parameters that mixed quite slowly. The efficiency of the SIS sampler greatly increased by analytically integrating out unknown parameters in the observation model. We consider that a careful implementation of MCMC for cases where data are informative relative to the priors sets the gold standard, but that SIS samplers are a viable alternative that can be programmed more quickly. Our SIS implementation is particularly competitive in situations where the data are relatively uninformative; in other cases, SIS may require substantially more computer power than an efficient implementation of MCMC to achieve the same level of MC error.

Gyrolithes as a multipurpose burrow: an ethologic approach
Renata Guimarães Netto
2007· Revista Brasileira de Paleontologia62doi:10.4072/rbp.2007.3.03

Spiral burrows perpendicular to the bedding plane are well known in the fossil record and are usually referred to the ichnogenus Gyrolithes. Common in Mesozoic and Cenozoic marginal-marine, brackish-water deposits, the only records of Gyrolithes in Paleozoic rocks are from the Cambrian. In Permian rocks of the Paran Basin (Rio do Sul and Rio Bonito formations), south Brazil, some short, irregularly spiraled burrows similar to Gyrolithes occur in marginalmarine, brackish-water siltstone and mudstone, closely associated with Thalassinoides, forming a Glossifungites suite. These burrows seem to play the same ethologic role of the corkscrew-shaped burrows that grade into modern Thalassinoides burrow systems. The corkscrew shape of Gyrolithes is assumed to represent a widespread architectural adaptation to deal with extreme salinity fluctuations in Mesozoic and Cenozoic brackish-water environments. However, spirals produced by thalassinidean shrimps in brackish water connected to modern Thalassinoides burrow systems are related to feeding activities. Instead of behavior to avoid extreme salinity fluctuations, the decapod spiral burrows may represent a feeding strategy to exploit organic-rich zones of the substrate in calm and protected environments. The discovery of spiral burrows in Permian marginal-marine stiffgrounds to firmgrounds indicates that this strategy was already adopted by some group of infaunal crustaceans in brackish-water ecosystems during the late Paleozoic.

How much is the western Mediterranean really warming and salting?
Manuel Vargas‐Yáñez, Patricia Zunino, Ayoub Benali, Michael Delpy +4 more
2010· Journal of Geophysical Research Atmospheres57doi:10.1029/2009jc005816

Instrumental biases and data processing methods can modify temperature trend estimations and enhance decadal variability in the upper ocean. These questions have not been specifically addressed in the western Mediterranean (WMED), a region where warming and salting trends have been detected during the second half of the twentieth century. In this work we test the sensitivity of these trends and decadal variability in the WMED to the use of bathythermograph data and data processing methods. We analyze different subbasins in order to detect distinct local responses. Our results show that deep waters in the WMED are increasing their temperature and salinity at a rate of 0.002°C/yr and 9.2 × 10 −4 yr −1 , respectively, from 1943. These trends are spatially homogeneous, not affected by instrumental biases, data processing methods, or changes in the period of time analyzed. The heat absorbed by the whole WMED is equivalent to a surface heat flux of 0.29 ± 0.19 W/m 2 . This figure encloses recent estimates of 0.36 ± 0.06 W/m 2 for the global ocean. The intermediate layer increased its salinity at a rate of 1.3 × 10 −4 yr −1 and this result can also be considered as robust. The intermediate layer temperature and the upper layer salinity show strong time variability and in our opinion long‐term changes cannot be statistically distinguished from decadal variability during the period 1943–2000. The upper layer shows a temperature and heat increase for the overall period, but it is caused by a steep warming trend initiated in the early 1980s.

A MSFD complementary approach for the assessment of pressures, knowledge and data gaps in Southern European Seas: The PERSEUS experience
A. Crise, Helen Kaberi, Javier Ruiz, А. Г. Зацепин +4 more
2015· Marine Pollution Bulletin53doi:10.1016/j.marpolbul.2015.03.024

PERSEUS project aims to identify the most relevant pressures exerted on the ecosystems of the Southern European Seas (SES), highlighting knowledge and data gaps that endanger the achievement of SES Good Environmental Status (GES) as mandated by the Marine Strategy Framework Directive (MSFD). A complementary approach has been adopted, by a meta-analysis of existing literature on pressure/impact/knowledge gaps summarized in tables related to the MSFD descriptors, discriminating open waters from coastal areas. A comparative assessment of the Initial Assessments (IAs) for five SES countries has been also independently performed. The comparison between meta-analysis results and IAs shows similarities for coastal areas only. Major knowledge gaps have been detected for the biodiversity, marine food web, marine litter and underwater noise descriptors. The meta-analysis also allowed the identification of additional research themes targeting research topics that are requested to the achievement of GES.

Lophius in the world: a synthesis on the common features and life strategies
A. Celso Fariña, Manuela Azevedo, J. Landa, Rafael Duarte +4 more
2008· ICES Journal of Marine Science51doi:10.1093/icesjms/fsn140

Abstract Fariña, A. C., Azevedo, M., Landa, J., Duarte, R., Sampedro, P., Costas, G., Torres, M. A., and Cañás, L. 2008. Lophius in the world: a synthesis on the common features and life strategies. – ICES Journal of Marine Science, 65: 1272–1280. Seven species of Lophius are known worldwide, six in the Atlantic Ocean and just one in the Northwest Pacific. The genus supports valuable fisheries (except for Lophius vaillanti), most for a long time, though the exploitation of Lophiusgastrophysus along the coast of Brazil is relatively recent. The manuscript reviews the current knowledge of phylogeographic and biological traits of Lophius species, pointing out common aspects in the life histories. Within the Lophiidae, the genus Lophius is phylogenetically the most derived, vicariance and dispersal having played a significant role in driving speciation. Life histories seem to have followed similar adaptive processes from a common ancestor along with similar environmental characteristics. The genetic structure of populations is poorly known, and usually, genetic differentiation is limited. Life-history aspects (age, growth, reproductive cycle, early stages, and feeding ecology) are addressed, and fisheries are reviewed. However, knowledge of many aspects of the biology and ecology (e.g. validation of the growth pattern, maturation processes, spawning areas and periodicity, recruitment processes, mortality, stock identification, and habitat needs) remains limited.

River plume fronts off NW Iberia from satellite observations and model data
Pablo Otero, M. Ruiz‐Villarreal, Álvaro Peliz
2009· ICES Journal of Marine Science49doi:10.1093/icesjms/fsp156

Abstract Otero, P., Ruiz-Villarreal, M., and Peliz, Á. 2009. River plume fronts off NW Iberia from satellite observations and model data. – ICES Journal of Marine Science, 66: 1853–1864. River plume fronts off NW Iberia during autumn 2002 are examined based on the gradient of the mixed layer depth (MLD) in three-dimensional model data and on sea surface temperature gradients in Advanced Very High Resolution Radiometer (AVHRR) imagery. The method reveals new aspects of the dynamics of fronts in the area. The strong gradient of the MLD between the plume and the adjacent ocean serves as a physical indicator of the maximum extension of the river plume and takes into account its three-dimensional structure as well as its surface signal. Differences in the position of river plume fronts are associated with local upwelling/downwelling conditions and their relaxation. During expansions of the plume induced by upwelling in late autumn, the shallower plume waters become colder and the thermal gradient with offshore waters increases. The model simulation also illustrates the existence of instabilities at the plume front and cross-shore variations in plume width that could induce the appearance of thermal gradients which can be resolved with AVHRR. Our simulations also show regional differences in front location, structure, and probability north (Galicia) and south (north Portugal) on the shelf, where bathymetry differs in shape and depth.

Representações e experiências das mulheres sobre a assistência ao parto vaginal e cesárea em maternidades pública e privada
Andréa de Sousa Gama, Karen Giffin, Antonia Angulo-Tuesta, Gisele Peixoto Barbosa +1 more
2009· Cadernos de Saúde Pública45doi:10.1590/s0102-311x2009001100017

This study analyzes the different representations and experiences of women from different social classes, including issues related to their relations with hospital staff in different institutional settings. This qualitative study focused on women who had experienced both types of delivery, in three maternity hospitals in Rio de Janeiro, Brazil (one public, one fully private, and another private under an outsourcing agreement with the public health system). The study showed that variations in public and private service models result in different types of delivery care and different relations with staff, and are reflected in different birthing experiences for the women. However, a critical gender perspective shows that in both cases, the service models reproduce the medicalization of childbirth and women's submission as objects in the birthing process. Although this is manifested in different ways in the three groups, the end result is to reduce the range of care and the possibility of women's empowerment during childbirth.

Sacrifice zones and the construction of urban energy landscapes in Concepción, Chile
Martín Sanzana Calvet, Vanesa Castán Broto
2020· Journal of Political Ecology45doi:10.2458/v27i1.23059

This article examines how national energy policies in Chile constitute urban energy landscapes characterized by environmental and spatial inequalities. The concept of urban energy landscapes is deployed to explain the spatial patterns resulting from energy governance and energy conflicts in the metropolitan area of Concepción, a metropolitan region of strategic importance in the configuration of national energy policy. These urban energy landscapes result from the constitution of 'sacrifice zones' that reflect an extractivist model of energy production. The combination of qualitative interviews and transect walks reveals different aspects of a dual arrangement of energy infrastructure and urbanization. The city's fragmented landscapes emerge from the coexistence of energy infrastructure and associated industries, with daily activities of communities that have little to do with these industries but live in their shadow. Conflicts in these urban energy landscapes are intense, with every inch of space contested by competing modes of 'being urban.' The urban energy landscape in Concepción is an expression of a clash of social and economic power with local priorities.

Acoustic and seismic imaging of the Adra Fault (NE Alboran Sea): in search of the source of the 1910 Adra earthquake
Eulália Gràcia, Rafael Bartolomé, Claudio Lo Iacono, Ximena Moreno +4 more
2012· Natural hazards and earth system sciences39doi:10.5194/nhess-12-3255-2012

Abstract. Recently acquired swath-bathymetry data and high-resolution seismic reflection profiles offshore Adra (Almería, Spain) reveal the surficial expression of a NW–SE trending 20 km-long fault, which we termed the Adra Fault. Seismic imaging across the structure depicts a sub-vertical fault reaching the seafloor surface and slightly dipping to the NE showing an along-axis structural variability. Our new data suggest normal displacement of the uppermost units with probably a lateral component. Radiocarbon dating of a gravity core located in the area indicates that seafloor sediments are of Holocene age, suggesting present-day tectonic activity. The NE Alboran Sea area is characterized by significant low-magnitude earthquakes and by historical records of moderate magnitude, such as the Mw = 6.1 1910 Adra Earthquake. The location, dimension and kinematics of the Adra Fault agree with the fault solution and magnitude of the 1910 Adra Earthquake, whose moment tensor analysis indicates normal-dextral motion. The fault seismic parameters indicate that the Adra Fault is a potential source of large magnitude (Mw ≤ 6.5) earthquakes, which represents an unreported seismic hazard for the neighbouring coastal areas.

Assessing the toxicity of chemical compounds associated with marine land-based fish farms: The use of mini-scale microalgal toxicity tests
Manoela R. de Orte, C. Carballeira, Inés G. Viana, A. Carballeira
2013· Chemistry and Ecology37doi:10.1080/02757540.2013.790381

Abstract Many chemicals that are currently used in aquaculture have not been evaluated with regard to their specific effects on the aquatic environment. In the present study, the toxic effects of several chemicals associated with land-based marine fish farming activities were assessed using two species of marine microalgae (Phaeodactylum tricornutum and Isochrysis galbana). Mini-scale toxicity tests were performed with six antibiotics (amoxicillin, ampicillin, flumequine, oxytetracycline, streptomycin and sulfadiazine) and two disinfectants (formaldehyde and hypochlorite). Amoxicillin and streptomycin did not exert toxic effects. Sulfadiazine was the most toxic chemical; the EC50 values were 0.11 mg/L and 1.44 mg/L for P. tricornutum and I. galbana respectively. As expected, the disinfectants displayed high toxicity, and P. tricornutum was particularly sensitive to these compounds. Although the differences in microalgal sensitivity depended on the chemical considered, both species were highly sensitive to most of the compounds tested. We recommend the inclusion of mini-scale microalgal toxicity tests in environmental risk assessment (ERA) and environmental monitoring plans because they are cost-effective and rapid. Keywords: bioassayecotoxicitygrowth testmicroplatephytoplanktonbiomonitoring Acknowledgements This work was funded by the National Plan for Marine Culture (JACUMAR 2008) within a project entitled 'Selección de indicadores, determinación de valores de referencia, diseño de programas y protocolos y medidas para estudios ambientales en acuicultura marina (INDAQUA).' M.R. De Orte, is grateful to the European Union for the Erasmus Mundus Scholarship provided. The authors are thankful to Dr. Jaime Fábregas of the Department of Microbiology and Parasitology (University of Santiago de Compostela, Spain) for providing the microalgae and culture medium.

Reproductive Biology of the Nonnative Oyster,<i>Crassostrea gigas</i>(Thunberg, 1793), as a Key Factor for Its Successful Spread Along the Rocky Shores of Northern Patagonia, Argentina
Cecilia Castaños, Marcela Pascual, A. Pérez Camacho
2009· Journal of Shellfish Research36doi:10.2983/035.028.0413

Crassostrea gigas was introduced in Anegada Bay (North Patagonia, Argentina), in 1981 for aquaculture purposes. The species has, since established in the field, covered all available hard substrata in the bay and gradually expanded south along the coast of the neighboring province of Río Negro, 90 km away from its original introduction site. Our work focused on the reproductive dynamics of the species at the introduction site, with emphasis on the thermal thresholds needed for each stage of gonad development. During early spring, the oysters in Anegada Bay go through active gonad proliferation. Maturity extends mainly from October to January. The first spawning occurs in November, when seawater temperature exceeds 17°C, and peaks from December to February, when seawater temperature lies in the range ot 19–21.5°C. The timing of gonad development is size dependent. Larger (≥70 mm) and medium-size oysters begin spawning first, whereas small oysters (<40 mm) represent the late spawners of the season. The C. gigas population in Anegada Bay is a clear and well-documented case of an introduction site where optimal environmental conditions are met, both for complete gonad maturation and for successful larval survival and settlement. We compiled a series of C. gigas cases from different parts of the world in which reproduction is related to seawater temperature. We concluded that the thermal threshold for full female gonad ripening in this species is strict (temperature > 17°C), and spawning only occurs in those sites where this threshold is reached.

Characteristics (abundance, type and origin) of beach litter on the Galician coast (NW Spain) from 2001 to 2010
Jesús Gago, Fernando Lahuerta, Pilar Antelo
2014· Scientia Marina35doi:10.3989/scimar.03883.31b

In order to assess the situation of beach litter on the Galician coast (NW Spain), we conducted a seasonal series of sampling on three beaches: A Lanzada, Baldaio and O Rostro. A total of 79 surveys were conducted from 2001 to 2010 on a stretch of 100 m and a stretch of 1 km. A total of 37862 beach litter items were counted and classified on the 100-m stretch and 7845 on the 1-km stretch. The average annual value of litter items for the 100-m beach stretch was 1016±633, 88±31 and 332±183; for the 1-km stretch, the average value of litter items was 163±87, 42±31 and 81±38, for A Lanzada, Baldaio and O Rostro beaches, respectively. The most common element found in beach litter was made of plastic, with average percent of 63, 38 and 83 for A Lanzada, Baldaio and O Rostro, respectively. We found that the main source of beach litter was the fishing and aquaculture sector, with an average percent value of 23, 14 and 38 for A Lanzada, Baldaio and O Rostro, respectively.