bluuebunny/crossref_metadata_2025 huggingface dataset:
Gonangium development and medusoid of Nemalecium lighti (Hargitt, 1924) (Cnidaria: Hydrozoa, Haleciidae)
Authors: Gravier-Bonnet Nicole , Migotto Alvaro E.
Published: October 2008

Based on live specimens of Nemalecium lighti collected in the coasts of La Réunion (Indian Ocean) and São Sebastião (Southeastern coast of Brazil) and kept in the laboratory, we observed the release of short-lived medusoids. The gonangia pass through six developmental phases: growing, ripening, migrating, stripping, liberating and spawning. The medusoids are tall, lack tentacles, bulbs, circular and radial canals, and the sexual products are packed around the eccentric manubrium; they are provided with a velum and with a subumbrellar ectoderm rich in transverse striated muscle fibers. There are refringent and isotropic corpuscles within vacuolated and ciliated large cells located around the aperture of the medusoid, which possibly function as statoliths. The corpuscles are similar to those already described for the families Plumulariidae and Aglaopheniidae. The gametes are liberated shortly after the release of the medusoid from the gonotheca. The female medusoid spawned 40-62 ova; spermatozoa exhibited a semicircular nucleus, and planulae were formed c. twelve hours after fertilization. Colonies with medusoids of only one sex or with both male and female medusoids.
Redescription of Tripoma arboretum Hirohito, 1995 (Hydrozoa: Campanulinidae) from the Tasman Sea with notes on quasi-parasitism of the species
Authors: Watson Jeanette E. , Vervoort W.
Published: October 2008

Tripoma arboreum Hirohito, 1995 has been found in deep water in the Tasman Sea south of Australia, the Norfolk Ridge north of New Zealand and Sagami Bay, Japan. The species exhibits unusual quasi-parasitic behaviour towards its host species.
Morphology and distribution of a deep-water Narcomedusa (Solmarisidae) from the northeast Pacific
Authors: Needler Arai Mary , Cavey Michael J. , Moore Beverley A.
Published: October 2008

Specimens of Solmaris sp. (Solmarisidae, Narcomedusae) with only four tentacles were collected in the northeast Pacific. The majority were collected in Canadian Pacific waters by Tucker trawl from stations outside the 500-m contour off the west coast of Vancouver Island, British Columbia, at depths of 300-700 m. Six were collected in vertical hauls at Station P (50oN, 145oW). The oral stomach wall contains three prominent rings of tissue. There is a peripheral ring of aggregates of gonadal tissue. Nematogenic areas with three types of nematocysts form an intermediate ring closer to the mouth than the gonads, and they also overlie the gonadal position where nematogenic tissue extends out to the base of each tentacle. Immediately surrounding the mouth, the epithelium of the oral stomach wall is greatly thickened, and this central ring contains large numbers of secretory cells.
Approaches to the ethology of hydroids and medusae (Cnidaria, Hydrozoa)
Authors: Miglietta M. P. , Della Tommasa L. , Denitto F. , Gravili C. , Pagliara P. , Bouillon J. , Boero F.
Published: October 2008

The behavioural patterns of 26 species of Antho- and Leptomedusae (with or without medusa stage) were investigated by video recordings. The analysed activities were: answers to mechanical stimuli, prey capture and ingestion, digestion, egestion, and swimming. The quantity of behavioural patterns identified in the small number of hydrozoan diversity studied so far is sufficient to demonstrate that these supposedly simple animals have evolved a complex array of responses to both external and internal stimuli.
Methodology to obtain accurate sea surface temperature from locally received NOAA-14 data in the Canary-Azores-Gibraltar area
Authors: Eugenio Francisco , Marcello J. , Hernández-Guerra A. , Rovaris E.
Published: October 2008

A methodology to obtain the sea surface temperature (SST) in the Canary-Azores-Gibraltar area has been developed. The final accuracy of the AVHRR-based SST retrievals depends both on the accuracy of the measured radiance and the accuracy of the SST retrieval algorithm that converts the measured radiance into sea surface temperature. The procedure made in this framework consists of: (i) a radiance-based non-linearity correction method; (ii) an automatic procedure for the geometric correction, achieving accuracy to the order of the pixel; (iii) an improved algorithm for cloud detection, based on the method of the multiband thresholds; (iv) a new split-window function (SWF) to perform atmospheric correction in CANIGO area. This task has been accomplished by using the matchup data set of AVHRR brightness temperature (channel 4 and 5) and in situ SST data. The matchups were carefully screened from the HRPT scenes of all seasons in 1996-1998. The temporal and spatial coincidences are within 30 minutes and one pixel resolution, respectively. Coefficients of that algorithm are estimated from regression analysis using 60 co-located in situ and satellite measurements (matchups). Error analysis has shown that SST can theoretically be retrieved to within 0.38ºC RMS.
Tidal currents and mixing in the Lake Maracaibo estuarine system
Authors: Antoranz Ana M. , Pelegrí J. L. , Masciangioli P.
Published: October 2008

The Lake Maracaibo estuarine system is a cooscillating coupled ocean-lake system connected through a partially mixed estuary. In this paper we examine the low frequency movements (w < 0.1 cycles/day) in the different water bodies within this system. The harmonic and rotary spectral analyses of velocity data indicates the importance of tidal forcing within the whole system and its interaction with winds and fresh water discharge. In particular, the results indicate the existence of dominant semi-monthly oscillations in Lake Maracaibo, likely of non-linear tidal origin, and suggest that vertical stratificaction plays an important role in controlling the three-dimensional structure of tidal currents.
Sensitivity of an idealized subtropical gyre to the eastern boundary conditions
Authors: Láiz I. , Sangrà P. , Pelegrí J. L. , Marrero-Díaz A.
Published: October 2008

The flow pattern of the North Atlantic Subtropical Gyre (NASG) is simulated using a highly idealised one-layer quasi-geostrophic wind-driven model. The novel feature of the model is the specification of the eastern boundary conditions. This is an upwelling favourable region with a quasi-permanent southward flowing coastal jet, which is fed by the eastern branch of the Canary Current. The corresponding boundary conditions are non-zero normal flux and constant potential vorticity, the latter being consistent with the generation of anticyclonic vorticity by the coastal jet. We examine the sensitivity of the model to the eastern boundary conditions and compare the results with recent observations for the region.
Applicability of T-S algorithms to the Canary Islands region
Authors: Marrero-Díaz A. , Pelegrí J. L. , Rodríguez-Santana A. , Sangrà P.
Published: October 2008

The high cost of oceanographic cruises often makes it advisable to use opportunity vessels for simple measurements, such as determining the temperature of the water column with expandable bathythermographs (XBT). In this work we examine the goodness and reliability of a method aimed at obtaining the maximum possible information from XBT data, and we apply it to the Canary Islands region. It consists in calculating analytic relations between temperature and salinity from historical conductivity-temperature-depth (CTD) data for the region, which are then used to hindcast/forecast the salinity and density distribution, as well as the distribution of other inferred quantities such as velocity. A hindcasting is carried out using direct independent temperature measurements obtained from a hydrographic cruise south of the island of Gran Canaria. At depths greater than 100-150 m the results show good agreement with the calculations obtained from CTD in situ data.
Seasonal and interannual variability of the Canary Current
Authors: Navarro-Pérez E. , Barton E. D.
Published: October 2008

Seasonal and interannual variability of the Canary Current on its passage through the Canary archipelago and between 20-35°N and 10-20°N are studied with long series of historical tide gauge, sea surface temperature and hydrographic data. The variability of winds is more seasonal in the north of the area, where they are weak and perpendicular to the coast in winter, than in the south, where winds are roughly parallel to shore all year though strongest in summer. Temperature and salinity data maps show a curved structure indicative of the subtropical gyre, which varies seasonally from North to South and from the open ocean to the coast. Dynamic height analyses show this seasonal variation of the gyre to depths of 200 m and indicate the existence of a meander-like diversion around the Canary Islands. The sea level in the Canary Islands also indicates a strong seasonal variation of the north Atlantic subtropical gyre. The southward geostrophic surface flow, derived from sea surface slope, was strongest during spring and summer at the eastern islands while it was strongest in winter at the outermost islands. The spatially averaged flow between the innermost and outermost islands shows the strongest southward flow in winter. Interannual variation of the flow between these islands, investigated during two periods, 1950-1956 and 1960-1973, reveals a mainly southward flow, although several show a northward tendency. The maximum equatorward velocity of the current in both periods is around 5 cm s-1, indicating a weak current.
Wind and tide current prediction using a 3D finite difference model in the Ría de Vigo (NW Spain)
Authors: Souto C. , Fariña-Busto E. , Alvarez L. , Rodríguez I.
Published: October 2008

A 3D barotropic finite difference model was adapted to reproduce the dynamics of the Ría de Vigo estuary, in the north-west corner of Spain. The model has been applied with astronomical tide and observed wind forcing data. The results are compared to data obtained by an AANDERAA DCM 12 acoustic Doppler current meter at one point of the Ría.
Zooplankton abundance in subtropical waters: is there a lunar cycle?
Authors: Hernández-León Santiago , Almeida C. , Yebra L. , Arístegui J. , Fernández de Puelles M. L. , García-Braun J.
Published: October 2008

Based on historical data of abundance, we report evidence of changes in zooplankton abundance in the 0-200 m layer related to the moon cycle confirming that this phenomenon is produced in the marine environment, similarly to the one described for freshwater ecosystems. A clear decrease in the abundance of copepodites plus copepods was observed from the second to the fourth quarter of the moon when the seasonal variability was suppressed. During the full moon phase the large zooplankton and micronekton of the deep scattering layers (DSL) would not reach the upper mixed layer in order to avoid predation because of the relatively high level of illumination. Thus epipelagic zooplankton abundance increases as the effect of a lower predatory pressure. Conversely, during the new moon phase the diel migrants reach the surface waters and epiplankton abundance considerably decreases. Recent oceanic sediment trap data in subtropical waters indicate that the particle flux increases at about 30 days period. Thus, the effect of diel vertical migrants could promote not only the variability in their resources and the intensity of the active flux, but could also drive the variability in the gravitational flux.
Aeolian sediment availability in coastal areas defined from sedimentary parameters. Application to a case study in Fuerteventura
Authors: Alcántara-Carrió J. , Alonso I.
Published: October 2008

Wind characteristics and availability of airborne sediments control aeolian dynamics. Availability of sediments has been only estimated from dune dimensions. Nevertheless, this method is not valid in serir (stone dessert) and sand sheets deposits, where surface properties better than volume of materials define their sediment availability. The area chosen for this study is the Isthmus of Jandía (Fuerteventura, Canary Islands), which presents a high diversity of present day aeolian environments. Grain-size and compositional parameters from surface samples permit the design of its sedimentary cartography, which shows spatial and seasonal variations of the aeolian dynamics. Values of these parameters have been combined by statistical analyses to obtain a new parameter, lineal combination of mean size, sorting, skewness, and carbonate content, which has been named the Aeolian Sediment Availability (ASA) parameter. The ASA parameter presents several advantages over the previous mobility diagrams (mean size vs sorting), since it considers more sedimentary variables, has a continuous numerical gradient which permits the plotting of maps of the aeolian sediment availability, and has a clear physical meaning. Dynamics inferred from this parameter are satisfactory compared with local wind data, empirical transport rates and landscape unit maps of the area.
Natural History: the sense of wonder, creativity and progress in ecology
Authors: Dayton Paul K. , Sala Enric
Published: October 2008

This essay addresses the question of blending natural history and ecological wisdom into the genuine creativity exemplified by Prof. Ramon Margalef. Many have observed that modern biology is a triumph of precision over accuracy, and that ecology has sought maturity by striving toward this model in which the precision value of the tools has supplanted important questions. In pursuing a model of hard science, ecology has struggled with Popperian approaches designed to create a thin patina of real science over the vast seas of uncertainty so admired by the naturalists. We start with a discussion of the importance of natural history in ecology and conservation, and the present state of natural history in academic ecology. We then discuss the respect for natural history in human cultures, and conclude that an infatuation with authority has obfuscated the important truths to be found in nature. We consider some general processes associated with creativity, and finally we ask how natural history influences creativity in ecology. We conclude that the soaring creativity exemplified by Ramon Margalef is based on a joyful almost spiritual understanding of natural history and the courage to avoid authority.
Following up on a Margalevian concept: Interactions and exchanges among adjacent parcels of coastal landscapes
Authors: Valiela I. , Bowen J. L. , Cole M. L. , Kroeger K. D. , Lawrence D. , Pabich W. J. , Tomasky G. , Mazzilli S.
Published: October 2008

Some decades ago Margalef speculated that study of the exchanges across boundaries that separate different types of ecological systems would provide significant insights about properties and processes within the units that make up ecological mosaics. Although such boundaries might be difficult to define, it seemed likely that such exchanges among units would influence the function and structure of the adjoined systems. In this paper we explore exchanges across such ecological boundaries in coastal ecosystems in Cape Cod, Massachusetts, and elsewhere. We find that, indeed, definition of such boundaries is ambiguous, but study of the exchanges is more useful. In the Cape Cod system, water transport down-gradient is the dominant mechanism exerting influence on down-gradient systems. The direction of ecological control across such boundaries is largely asymmetrical, and properties of up-gradient units exert significant influence on down-gradient units. General properties of donor and receptor parcels are hard to discern, but clearly, parcels making up an ecological mosaic are not independent units, but are coupled by transfers from upgradient tesserae. Studies of controls of ecological systems need to include inter-unit influences as well as internal mechanisms.
Caught in the food web: complexity made simple?
Authors: Pomeroy Lawrence R.
Published: October 2008

Several historically separate lines of food-web research are merging into a unified approach. Connections between microbial and metazoan food webs are significant. Interactions of control by predators, defenses against predation, and availability of organic and inorganic nutrition, not any one of these, shape food webs. The same principles of population ecology apply to metazoans and microorganisms, but microorganisms dominate the flux of energy in both marine and terrestrial systems. Microbial biomass often is a major fraction of total biomass, and very small organisms have a very large ratio of production and respiration to biomass. Assimilation efficiency of bacteria in natural systems is often not as high as in experimental systems, so more primary production is lost to microbial respiration than had been thought. Simulation has been a highly useful adjunct to experiments in both population theory and in studies of biogeochemical mass balance, but it does not fully encompass the complexity of real systems. A major challenge for the future is to find better ways to deal with the real complexity of food webs, both in modeling and in empirical observations, and to do a better job of bringing together conceptually the dynamics of population processes and biogeochemistry.
Conversaciones con Ramón: big questions for the millennium
Authors: Golley Frank B.
Published: October 2008

Ramon Margalef and I have enjoyed many years of conversation about ecology and my remarks will celebrate our relationship. My life has gradually shifted from the hustle of the market place and consumption of money and goods to a academic career devoted to students and ideas. Students ask how they can avoid becoming trivial, how they can contribute to solving the dreadful problems that face human society? Students want to know from me, their senior, what are the big questions of ecological science. That is the motivation for me to think about the challenging questions ecologists are asking today, that may change the subject tomorrow.
The oceanic fixed nitrogen and nitrous oxide budgets: Moving targets as we enter the anthropocene?
Authors: Codispoti L. A. , Brandes Jay A. , Christensen J. P. , Devol A. H. , Naqvi S.W. A. , Paerl Hans W. , Yoshinari T.
Published: October 2008

New data force us to raise previous estimates of oceanic denitrification. Our revised estimate of ~ 450 Tg N yr-1 (Tg = 1012 g) produces an oceanic fixed N budget with a large deficit (~ 200 Tg N yr-1) that can be explained only by positing an ocean that has deviated far from a steady-state, the need for a major upwards revision of fixed N inputs, particularly nitrogen fixation, or both. Oceanic denitrification can be significantly altered by small re-distributions of carbon and dissolved oxygen. Since fixed N is a limiting nutrient, uncompensated changes in denitrification affect the ocean´s ability to sequester atmospheric CO2 via the "biological pump". We have also had to modify our concepts of the oceanic N2O regime to take better account of the extremely high N2O saturations that can arise in productive, low oxygen waters. Recent results from the western Indian Shelf during a period when hypoxic, suboxic and anoxic waters were present produced a maximum surface N2O saturation of > 8000%, a likely consequence of "stop and go" denitrification. The sensitivity of N2O production and consumption to small changes in the oceanic dissolved oxygen distribution and to the "spin-up" phase of denitrification suggests that the oceanic source term for N2O could change rapidly.
Distribution, abundance and biological features of anglerfish (Lophius piscatoirus and Lophhius budegassa) (Osteichthyes: Lphiiformes) in the Mediterranean Sea
Authors: Ungaro Nicola , Marano Giovanni , Auteri Roberto , Voliani Alessandro , Massutí Enric , García-Rodríguez Mariano , Osmani Kastriot
Published: October 2008

The distribution and biological features of anglerfish (Lophius piscatorius and L. budegassa) in the Mediterranean Sea were analysed from trawl surveys data (MEDITS project, years 1994-1999). The above-mentioned species were widely distributed in the Mediterranean, but differences in abundance were found according to geographic sectors and depths. Most of the collected specimens belonged to the first length cohorts and length distributions also differed at macro-area levels. Mean sizes at female sexual maturity were estimated at 68.5 cm and 66.2 cm total length, respectively for L. piscatorius and L. budegassa.
Geographical distribution, abundance and some population characteristics of the species of the genus Pagellus (Osteichthyes: Percirformes) in different areas of the Mediterranean
Authors: Spedicato Maria Teresa , Greco Silvestro , Sophronidis Kostas , Lembo Giuseppe , Giordano Daniela , Argyri Anna
Published: October 2008

The objective of this paper was to investigate the local distribution, abundance and population structure of Pagellus erythrinus, Pagellus bogaraveo and Pagellus acarne on the continental shelf and slope over a wide geographic area from Gibraltar to the Aegean Sea. The analysis was based on the data collected during six trawl surveys, from 1994 to 1999, carried out yearly in spring within the MEDITS EU project. P. acarne was mainly distributed on the continental shelf, with a relatively higher abundance in the western part of the Mediterranean basin, where the biomass indices of P. bogaraveo were also important on the continental slope. Throughout the studied area, P. erythrinus was mainly distributed on the continental shelf, with remarkable abundance indices in the eastern part of the Mediterranean and in Corsica´s waters. Mean total lengths showed a highly significant decreasing trend from the western to the eastern geographical sectors.
Distribution and abundance of Citharus linguatula, Lepidorhombus boscii (Risso, 1810) and Solea vulgaris, (Osteichthyes, Pleuronectiformes) in the Mediterranean Sea
Authors: Sartor Paolo , Sbrana Mario , Ungaro Nicola , Marano Chiara A. , Piccinetti Corrado , Piccinetti Manfrin Gabriella
Published: October 2008

Information on distribution, relative abundance and size composition of the pleuronectiform species Citharus linguatula, Lepidorhombus boscii and Solea vulgaris was obtained during the MEDITS trawl surveys, carried out in a wide area of the Mediterranean Sea from 1994 to 1999. The three species showed a wide geographic distribution, as they were collected in all the macro-areas investigated, but with some differences in degree of presence among the 40 geographic sectors. Variations in abundance indices, analysed on a spatio-temporal basis with a Generalised Linear Model, were mostly related to the depth stratum and the macro-area. C. linguatula and S. vulgaris were especially found from 10 to 100 m depth, while L. boscii was most abundant on bottoms ranging from 100 to 500 m depth. The three species showed the highest abundance indices (kg/km2) in the Gulf of Lions, in the Greek Seas and along the Sardinian coasts. Especially for L. boscii and C. linguatula, the demographic structure showed that the sampled populations were mainly constituted by juveniles. The lowest biomass and abundance indices were obtained for S. vulgaris, whose catch was mainly composed of adult fish.
How may feeding data be integrated into a model for a Norwegian fjord population of cod (Gadus morhua L.) ?
Authors: Pedersen Torstein , Pope John G.
Published: October 2008

We investigate how cod feeding data may be included into a recently developed age-structured model for a coastal cod population in a small fjord in northern Norway. The model integrates data from mark-recapture experiments, trawl-surveys and commercial catches. The fjord population has high biomass density (2-3 tonnes km-2) and low fishing mortality rates (F
Incorporating time-series structure in medium-term recruitment projections
Authors: Needle C. L. , O'Brien C. M. , Darby C. D. , Smith M. T.
Published: October 2008

One of the key tasks in current fisheries research is to improve the performance, in terms of accuracy and utility, of projections of recruitment-driven population dynamics in the medium-term. Reliable indications of the median level and variability of recruitment over a five- to ten-year time-scale would be invaluable in the determination of appropriate levels of fishing mortality, in order to attempt to maintain sustainable fish stocks. Building upon the stochastic simulation approach currently adopted within ICES stock assessment working groups, this paper investigates the use of time-series models to characterise the historical development of residuals to fitted stock-recruitment models. We use the probability of SSB (spawning stock biomass) falling below Bpa (precautionary value of spawning stock biomass) over a range of multipliers on imposed fishing mortality as a diagnostic statistic to compare projections. Case studies of commercially-important fish stocks are presented (North Sea cod, haddock and whiting), and the potential implications of the new approaches for fisheries management are discussed.
What kinds of fish stock predictions do we need and what kinds of information will help us to make better predictions?
Authors: Brander Keith
Published: October 2008

Fish stock predictions are used to guide fisheries management, but stocks continue to be over-exploited. Traditional single-species age-structured stock assessment models, which became an operational component of fisheries management in the 1950s, ignore biological and environmental effects. As our knowledge of the marine environment improves and our concern about the state of the marine ecosystem and about global change increases, the scope of our models needs to be widened. We need different kinds of predictions as well as better predictions. Population characteristics (rates of mortality, growth, recruitment) of 61 stocks of 17 species of NE Atlantic fish are reviewed in order to consider the implications for the time-scale and quality of stock predictions. Short life expectancy limits the time horizon for predictability based on the current fishable stock and predictions are therefore more dependent on estimates or assumptions about future rates. Evidence is presented that rates of growth and recruitment are influenced by environmental factors and possibilities for including new information are explored in order to improve predictions.
Assessment of golden redfish (Sebastes marinus L) in Icelandic waters
Authors: Björnsson Höskuldur , Sigurdsson Thorsteinn
Published: October 2008

Assessment of redfish has traditionally suffered from the inability to age the fish. For golden redfish in Icelandic waters, length distributions and abundance indices are available both from commercial catch and from surveys, particularly a groundfish survey in March. This paper addresses the use of an age- and length-based cohort model for the assessment of redfish, where all selection curves depend on the length of the fish and information on age is not a prerequisite but can be utilised if available. In the last few years it appears that ageing of this species has been successful and in this paper we compare assessment results of a model that incorporates age information with those that do not. Finally, we calculate yield per recruit, Fmax and F0.1 for the stock. Stock size, catch and fishing mortality are then simulated 10 years ahead using different catch control laws.
Forecasting recruitment and stock biomass of Northeast Arctic cod using neural networks
Authors: Huse Geir , Ottersen Geir
Published: October 2008

We apply an artificial neural network (ANN) to predict recruitment and biomass development of Northeast Arctic cod. The ANN is trained using a genetic algorithm with input time series such as spawning stock biomass of cod, herring and capelin biomass, and temperature. Forecasts were made by training the ANN on parts of the time series (training set), and then using a trained ANN to predict cod recruitment or biomass in years outside of the training set. In general the predictions corresponded well to observations. The correlation (r2) between observed and predicted stock recruitment at age 3 was 0.74, based on a model with temperature, spawning stock biomass, and capelin biomass. The correlation between observed and predicted stock biomass was 0.89, 0.72 and 0.57 for one, two and three year predictions respectively. The best model for the one year predictions was based on input information on cod biomass, temperature, and cod landings. These results illustrate the strong forecasting ability of ANN models. In the light of our findings we discuss the potential benefit of applying ANN models as a forecasting technology in fisheries assessment.
A bioeconomic model for Mediterranean fisheries, the hake off Catalonia (western Mediterranean) as a case study
Authors: Lleonart J. , Maynou F. , Recasens L. , Franquesa R.
Published: October 2008

The theoretical aspects and the associated software of a bioeconomic model for Mediterranean fisheries are presented. The first objective of the model is to reproduce the bioeconomic conditions in which the fisheries occur. The model is, perforce, multispecies and multigear. The main management procedure is effort limitation. The model also incorporates the usual fishermen strategy of increasing efficiency to obtain increased fishing mortality while maintaining the nominal effort. This is modelled by means of a function relating the efficiency (or technological progress) with the capital invested in the fishery and time. A second objective is to simulate alternative management strategies. The model allows the operation of technical and economic management measures in the presence of different kind of events. Both deterministic and stochastic simulations can be performed. An application of this tool to the hake fishery off Catalonia is presented, considering the other species caught and the different gears used. Several alternative management measures are tested and their consequences for the stock and economy of fishermen are analysed.
Nesting seabirds in SE Spain: distribution, numbers and trends in the province of Almería
Authors: Paracuellos Mariano , Nevado Juan Carlos
Published: October 2008

Little is known on the abundance of seabirds breeding in southeastern Spain. This study reports on the distribution, numbers and population trends of breeding colonies of this avian group in this region. Principally from 1996 to 2000, the coast of the province of Almería was surveyed during the breeding season. In 2000, the last year of survey, we counted 1,731 seabird breeding pairs, corresponding to 8 species. The yellow-legged gull Larus cachinnans was the most abundant seabird with more than 50% of the total, followed by Audouin´s gull Larus audouinii, the little tern Sterna albifrons, the black-headed gull Larus ridibundus and the common tern Sterna hirundo. Cory´s shearwater Calonectris diomedea, the shag Phalacrocorax aristotelis and the European storm petrel Hydrobates pelagicus bred in small numbers. The black-headed Gull, yellow-legged gull and common tern showed increasing trends over the last decade. The most important breeding sites were Alborán Island and the sea cliffs of Cabo de Gata, La Higuera and Cabrera. A main factor influencing increasing population trends was the lack of human disturbance at legally protected breeding sites.
Preliminary results on the foraging ecology of Balearic shearwaters (Puffinus mauretanicus) from bird-borne data loggers
Authors: Aguilar Juan Salvador , Benvenuti Silvano , Dall'Antonia Luigi , McMinn-Grivé Miguel , Mayol-Serra Joan
Published: October 2008

A data logger devised and manufactured by our research team in order to study the homing routes of carrier pigeons was subsequently modified to study the homing behaviour and foraging strategies of breeding marine birds. Recent versions of the data logger, equipped with a flight sensor and depth meter or saltwater switch, were used in a study of the foraging strategies of chick-rearing Balearic shearwaters (Puffinus mauretanicus) in the framework of the project LIFE-Puffinus financed by the Balearic Government and the EU. Due to low recapture rates (only 3 out of 6 tagged birds were recovered), only preliminary data from a small sample are available. Data loggers have recorded data on the pattern of nest attendance (including departure time to foraging trips and return time) and the diurnal pattern of flight and dive activity (including depth and duration of dives). Despite the small sample size, the results show that our data loggers can successfully be applied to the study of the breeding biology and foraging ecology-including the diving pattern-of Balearic shearwaters and similar species.
Using stable isotopes of nitrogen and carbon to study seabird ecology: applications in the Mediterranean seabird community
Authors: Forero Manuela G. , Hobson Keith A.
Published: October 2008

The application of the stable isotope technique to ecological studies is becoming increasingly widespread. In the case of seabirds, stable isotopes of nitrogen and carbon have been mainly used as dietary tracers. This approach relieson the fact that food web isotopic signatures are reflected in the tissues of the consumer. In addition to the study of trophic ecology, stable isotopes have been used to track the movement of seabirds across isotopic gradients, as individuals moving between isotopically distinct foodwebs can carry with them information on the location of previous feeding areas. Studies applying the stable isotope methodology to the study of seabird ecology show a clear evolution from broad and descriptive approaches to detailed and individual-based analyses. The purpose of this article is to show the different fields of application of stable isotopes to the study of the seabird ecology. Finally, we illustrate the utility of this technique by considering the particularities of the Mediterranean seabird community, suggesting different ecological questions and conservation problems that could be addressed by using the stable isotope approach in this community.
Mediterranean seabird conservation: what can we do?
Authors: Mínguez Eduardo , Oro Daniel , De Juana Eduardo , Martínez-Abraín Alejandro
Published: October 2008

Human activities in the Mediterranean determine, to a large extent, the availability of food and breeding sites for seabirds, the two most important ecological requirements for breeding seabirds. Food availability is highly dependent on fisheries activities and the availability of breeding sites is largely related with tourism pressure. Conservation plans necessarily need to incorporate the fact that Mediterranean seabirds and human activities are forced partners. However, solutions are complex because fishing policies are not commonly designed by environmental agencies and also because seabirds are organized in metapopulations which do not coincide with administrative borders. In this monographic volume, several authors describe the main characteristics of the Mediterranean seabird community, identify its conservation problems and suggest a number of technical solutions.
Species Action Plans for the conservation of seabirds in the Mediterranean Sea: Audouin's gull, Balearic shearwater and Mediterranean shag
Authors: Gallo-Orsi Umberto
Published: October 2008

BirdLife International has so far developed Action Plans for 37 bird species. The plans, although not legally binding, have been approved by the Ornis Committee (EU DG Environment) and most of them have also been endorsed by the Standing Committee of the Bern Convention. Three of the species covered by the SAPs are Mediterranean seabirds: Audouin´s gull (Larus audouinii), Balearic shearwater (Puffinus mauretanicus) and Mediterranean shag (Phalacrocorax aristotelis desmarestii). The documents, which have been produced through a participatory process involving tens of experts across the range of the taxa, provide information on the biology, ecology and threats, but the most important feature is the list of specific objectives and actions which are ranked according to their priority and urgency. Alongside actions addressing species-specific conservation needs, such as site protection and management, a number of activities aimed at the conservation of these species are common and refer to wide policies such as land-use planning, fishery, tourist development and pollution control. The documents represent the most up-to-date and scientifically-based source of information for planning and implementing conservation activities across the Mediterranean, to be implemented by both governmental and non governmental organisations.
Lifetime reproductive success in seabirds: interindividual differences and implications for conservation
Authors: Moreno Juan
Published: October 2008

Seabirds share certain life history traits, most species being relatively longlived and reproducing at a low rate. Long-term population studies of seabirds have revealed that lifetime reproductive success differs widely among individuals, and that only a minor fraction of the population contributes importantly to future generations. These individuals have traditionally been termed of high parental quality. Quality is often defined tautologically as breeding success. Determinants of parental quality, and ways to measure it a priori without relying on breeding success, remain a challenge in seabird ecology. Parental health state and immunocompetence have been shown to be associated with breeding date, egg size, chick growth rate and breeding success in several field studies and may allow the identification of good breeders. Identifying the high quality fraction in a population may be worthwhile in order to better guarantee the productivity of declining populations.
Kleptoparasitism, disturbance and predation of yellow-legged gulls on Audouin's gulls in three colonies of the western Mediterranean
Authors: Martínez-Abraín Alejandro , González-Solis Jacob , Pedrocchi Vittorio , Genovart Meritxell , Abella Joan Carles , Ruiz Xavier , Jiménez Juan , Oro Daniel
Published: October 2008

The impact of yellow-legged gulls on Audouin´s gulls was studied by means of observations from a blind, at the Ebro Delta, the Chafarinas Islands and the Columbretes Islands colonies, during different stages of Audouin´s Gulls breeding cycle. The rates of predation (upon eggs and chicks) and kleptoparasitism (aerial and on courtship and chick-feeding regurgitates) were recorded to evaluate this impact. Kleptoparasitism and predation rates recorded at the three colonies may be considered low when compared with similar studies dealing with other gull species. It seems that interactions did not represent a threat to the population dynamics of Audouin´s Gulls in any of the three colonies. The highest rates of aerial kleptoparasitism, courtship feeding and chick mortality were recorded at the Columbretes Islands, and the lowest at the Ebro Delta. The ratio of the number of yellow-legged gulls to the number of Audouin´s gulls seems to influence the rate of disturbances. Food availability was also likely to play an important role in the number of interactions, which increased when food was in shorter supply. The study at the Ebro Delta and Chafarinas Islands was restricted to some subcolonies and hence results may not be necessarily representative of the entire colonies. The existence of some yellow-legged gull individuals specialised as predators was recorded. Finally, we discuss the suitability of several conservation measures commonly applied in colonies where both species breed syntopically.
Resting stage in the biogenic fraction of surface sediments from the deep Mediterranean Sea
Authors: Della Tommasa Luigi , Danovaro Roberto , Belmonte Genuario , Boero Ferdinando
Published: October 2008

The presence of resting stages in neritic areas is well known, while their occurrence in the deep sea realm has seldom been considered. Recent investigations showed strict interactions between neritic and deep sea domains, due to up- and down-welling phenomena driven by submarine canyons. To estimate the presence of resting stages in deep bottom sediments, seven sediment cores, collected along a trans-Mediterranean transect by means a multi-corer during the TRANSMED survey (1999), were studied. Most biogenic sediment was composed of Foraminifera tests (tens of thousand tests cm-3), Calciodinellum albatrosianum and Leonella granifera (Dinophyta) cysts (up to thousands cysts cm-3). Eleven dinocyst morphotypes were recorded mainly as empty shells (seven calcareous-walled: C. albatrosianum, Calciperidinium asymmetricum, Leonella granifera, Scrippsiella trochoidea, S. precaria type 1, S. precaria type 2, S. regalis; four organic-walled: Impagidinium aculeatum, unid. dinocyst 1, unid. dinocyst 2 and unid. dinocyst 3), while no metazoan resting eggs were observed. The presence of viable resting stages in deep bottom surface sediments was much lower than in neritic areas, suggesting that oceanic species do not produce cysts for a "benthic resting" strategy. Further taxonomic and biogeographic studies are needed to better understand the ecological dynamics of oceanic plankton in the Mediterranean Sea.
Distribution of charophyte species in Estonian coastal water (NE Baltic Sea)
Authors: Torn Kaire , Martin Georg , Kukk Henn , Trei Tiiu
Published: October 2008

Charophytes constitute a group of macrophytes that usually inhabit soft bottoms with shallow water. They occur mostly in fresh-water environments but can also be found in brackish waters. Due to their requirement for clear water they are considered sensitive to eutrophication and therefore often used as an indicator for good water quality. The diverse structure of the Estonian coastline with its numerous sheltered bays and shallow, soft-bottom archipelago areas coupled with low salinity conditions provides an excellent habitat for charophytes. To date, seven species have been described in Estonian coastal waters, NE Baltic Sea. Last systematic investigations on charophyte distribution date back 20-30 years. During the summer of 2001 the locations where charophytes have previously been found were revisited and new sites sampled, to describe the present distribution of quantitative and qualitative parameters of charophyte species. Sampling was performed mainly by SCUBA diving; occurrence, abundance and wet weight biomass were estimated for each location. Six species of charophytes were identified. Compared to previously recorded material, no significant changes in the distribution pattern of charophytes were found. The dependence of charophyte distribution on environmental settings was tested, with depth and substrate quality explaining most of the variability in distribution. Salinity within observed range had minor influence on charophytes.
The utiquity and many roles of exopolymers (EPS) in aquatic systems
Authors: Wotton Roger S.
Published: October 2008

Exopolymers (EPS) are produced by unicellular and multicellular organisms. They consist largely of polysaccharides that hydrate rapidly on contact with water and link to form gels. EPS have many uses: in attachment; in locomotion on substrata; as a protection against predators, pathogens and changes in physico-chemical conditions; as a means of overcoming the threat of desiccation; in preventing abrasion; and in feeding. When free of organisms, some EPS form loosely associated polymer gels that are important in the development of organic matter aggregates. These aggregates, together with mucus-bound faecal pellets, play an essential role in nutrient cycling, and in the metabolism of ecosystems.;
Bioconstruction and biodiversity: their mutual influence
Authors: Cocito Silvia
Published: October 2008

This paper describes the functional role of main benthic constructor organisms and reviews processes by which bioconstructions increase diversity and abundance of associated biota, and the reverse. Based on the literature, patterns of diversity of carbonate bryozoan bioconstructions, one of the most important groups performing important constructional roles, have been analysed. Diversity of bryozoan bioconstructors seems not to follow the latitudinal gradient, from tropics to increasing distance from tropics, recognised for coral bioconstructors. The only case of a high diversity bryozoan reef (Joulters Cays, Bahamas) represents a situation virtually unique in carbonate environments. Dimension and extension of bryozoan bioconstructions show their maximum in temperate environments, where seasonality or variability of environmental parameters could afford advantages for success to bryozoans. With only one exception (the bryozoan-serpulid build-ups from South Australia), diversity of biota associated with bryozoan bioconstructions is high, but comparison is not possible due to the fact that exhaustive faunal studies are rare, sometimes referring only to one taxon, and environments differing in depth range, salinity, hydrodynamics, trophic diversity, etc. are involved.
The present-day Mediterranean brachiopod fauna: diversity, life habits, biogeography and paleobiogeography
Authors: Logan A. , Bianchi C. N. , Morri C. , Zibrowius H.
Published: October 2008

The present-day brachiopods from the Mediterranean Sea were thoroughly described by nineteenth-century workers, to the extent that Logan´s revision in 1979 listed the same 11 species as Davidson, almost 100 years earlier. Since then recent discoveries, mainly from cave habitats inaccessible to early workers, have increased the number of species to 14. The validity of additional forms, which are either contentious or based on scanty evidence, is evaluated here. Preferred substrates and approximate bio-depth zones of all species are given and their usefulness for paleoecological reconstruction is discussed. A previous dearth of material from the eastern Mediterranean has now been at least partially remedied by new records from the coasts of Cyprus, Israel, Egypt, and, in particular, Lebanon and the southern Aegean Sea. While 11 species (79 % of the whole fauna) have now been recorded from the eastern basin, Terebratulina retusa, Argyrotheca cistellula, Megathiris detruncata and Platidia spp. appear to be less common than in the western basin. Lacazella mediterranea, Tethyrhynchia mediterranea and Gwynia capsula have not yet been recorded from the eastern Mediterranean, but whether this is due to a west-east faunal impoverishment or insufficient collecting is uncertain. L. mediterranea and T. mediterranea may be endemic to the Mediterranean. The Messinian (Late Miocene) salinity crisis caused most species to disappear from the ancestral Mediterranean Sea. T. mediterranea may be a paleoendemic that has survived in marine refuges mostly located on the outer margin of the western basin, while other species either entered or re-entered the Mediterranean from the Atlantic after the Miocene.
Intertidal water column meiofauna in relation to wave intensity on an exposed beach
Authors: Rodríguez J. Germán
Published: October 2008

Since the 1970s, various studies have shown that some meiofaunal taxa frequently occur in the water column. Water currents or any process that disturbs the sediments are possible factors that can facilitate the passive entry of meiofauna in the water column. Wave action has been predicted as one of these factors (Armonies, 1994), suggesting a correlation between the number of eroded specimens and wave intensity should exist. As a test of this prediction, replicated samples were taken in the water column, swash sediment and back-swash water in an exposed beach (Island of Sylt, northern Wadden Sea). Wave height and period were measured to characterise the energy regime. Samplings were carried out over a nine day period in August 2000, at diurnal mid-tide time. Wave height and period varied significantly among collections. Densities of nematodes, harpacticoids, nauplii, platyhelminthes, ostracods and bivalve larvae in the water column, swash sediment and back-swash water varied significantly among collections. Nevertheless, no significant correlation was found between water column density and wave characteristics. Density of meiofauna in the water column was not correlated with density in the sediment or in back-swash water. Therefore wave intensity did not explain the variability of meiofaunal densities present in the water column.