bluuebunny/crossref_metadata_2025 huggingface dataset:
Feeding ecology of the gobies Pomatoschistus minutes (Pallas, 1770) and Pomatoschistus microps (Krøyer, 1838) in the upper Tagus estuary, Portugal
Authors: Salgado Joao Pedro , Nogueira Cabral Henrique , Costa María José
Published: October 2008

The sand goby Pomatoschistus minutus (Pallas, 1770) and the common goby Pomatoschistusmicrops (Krøyer, 1838) are among the most abundant fish species in estuaries, lagoons and along the Atlantic shores of Europe. In the Tagus estuary these species are particularly important in the food web. Fish samples were taken monthly in the upper estuary, and the gut contents of a total of 431 P.minutus and 382 P. microps were analysed in order to study preferences and seasonal changes in their diets and to understand intra- and interspecific relations between these two congeneric gobies. The sand goby had no dominant prey, although mysids were particularly important in the diet of this species. Shrimps and polychaetes were also common prey. P.microps preferentially ingested polychaetes, with isopods, amphipods, bivalves and copepods as secondary prey items. Significant seasonal variations in the ingestion of the main prey groups of both species were obtained, which reflect variations in prey availability. During the reproductive season there were differences in the food consumed by males and females, mainly for P.minutus, reflecting the different activity pattern exhibited by males and females during the breeding season, since parental care is supported by the former. The smallest classes from P.minutus increased their niche widths as they grew. Due to the different length reached by each species, the degree of interspecific overlap decreased with increasing body size.
Estimates of gradient Richardson numbers from vertically smoothed data in the Gulf Stream region
Authors: Van Gastel Paul , Pelegrí Josep L.
Published: October 2008

We use several hydrographic and velocity sections crossing the Gulf Stream to examine how the gradient Richardson number, Ri, is modified due to both vertical smoothing of the hydrographic and/or velocity fields and the assumption of parallel or geostrophic flow. Vertical smoothing of the original (25 m interval) velocity field leads to a substantial increase in the Ri mean value, of the same order as the smoothing factor, while its standard deviation remains approximately constant. This contrasts with very minor changes in the distribution of the Ri values due to vertical smoothing of the density field over similar lengths. Mean geostrophic Ri values remain always above the actual unsmoothed Ri values, commonly one to two orders of magnitude larger, but the standard deviation is typically a factor of five larger in geostrophic than in actual Ri values. At high vertical wavenumbers (length scales below 3 m) the geostrophic shear only leads to near critical conditions in already rather mixed regions. At these scales, hence, the major contributor to shear mixing is likely to come from the interaction of the background flow with internal waves. At low vertical wavenumbers (scales above 25 m) the ageostrophic motions provide the main source for shear, with cross-stream movements having a minor but non-negligible contribution. These large-scale motions may be associated with local accelerations taking place during frontogenetic phases of meanders.
Uncertainties in sampling procedures for age composition of hake and sardine in Iberian Atlantic waters
Authors: Jardim Ernesto , Trujillo Valentin , Sampedro Paz
Published: October 2008

Estimates of the age composition of hake (demersal) and sardine (pelagic) in Iberian Atlantic waters in 1999 are analysed, paying specific attention to sampling variability. Two methods are applied, one based on an analytical approach and the other on simulation using a non-parametric bootstrap technique. The methods were used to estimate the catch at age by numbers per species for 1999, and the associated variability. They provide a useful means of analysing the precision of the estimates, of assessing data quality, and of optimising different sampling schemes. The estimates are precise for the reference ages used in assessment (CV < 13% for both species). The bootstrap method is considered better owing to its non-parametric nature, despite its more complicated implementation and greater need of computational resources.
A pressurising system for long-term study of marine or freshwater organisms enabling the simulation of cyclic vertical migrations
Authors: Damasceno-Oliveira Alfredo , Gonçalves José , Silva Joao , Fernández-Durán Begoña , Coimbra Joao
Published: October 2008

A computer-controlled pressurising system enabling large aquatic organisms like marine fishes to be maintained for long periods is described. The paper presents a system that is capable not only of maintaining constant hydrostatic pressures but also of producing any desired cyclic variations of that parameter, allowing the close and reliable simulation of vertical migrations that many species of fishes and other aquatic animals perform during some stages of their life cycles.
Population structure of the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) (Crustacea: Penaeoidea) in the littoral of São Paulo, Brazil
Authors: Castro Rodrigo H. , Costa Rogerio C. , Fransozo Adilson , Mantelatto Fernando L.
Published: October 2008

The population structure of the penaeidean shrimp Xyphopenaeus kroyeri was studied in Ubatuba Bay, Ubatuba, São Paulo, Brazil. The period and site of juvenile recruitment were monitored using a monthly sampling design with eight fixed areas (transects) from September 1995 to August 1996. The population structure was assessed using size frequency distributions (based on carapace length) for each month and sampling area. Females were significantly larger than males, suggesting a differential growth between sexes. The very low occurrence of large adults in the Bay can be related to offshore migration for reproduction. Recruitment occurred throughout the year, with a peak during the summer, when the highest recruitment rates were obtained along inshore transects. The present investigation revealed valuable information on the biology of the species mainly in the study region, which is considered a nursery ground for juveniles of X. kroyeri. The species showed an important variation from the typical life cycle that it is assumed to hold over its entire range and X. kroyeri should be classified as having a life cycle different from that proposed previously in the literature, i.e. the juveniles prefer inshore areas instead of estuaries. Some suggestions for the seabob fishery management are proposed as an alternative for minimising the impact during the harvest period and adjusting the protection schedule.
Annual growth and age composition of the squat lobster Cervimunida johni off northern-central Chile (1996-97)
Authors: Arancibia Hugo , Cubillos Luis A. , Acuña Enzo
Published: October 2008

The MULTIFAN method was used to analyse a series of monthly length-frequency distributions of the squat lobster Cervimunida johni Porter (1903) (Galatheidae), for the estimation of growth and age composition in the fishing area off Coquimbo (29°59’S-71°22’W), in the northern-central area off Chile. Length frequency data (LFD) were collected from commercial catches made between 28°S and 32°10’S from September 1996 to September 1997. MULTIFAN distinguished 11 age classes in the LFD of males and 9 age classes in the LFD of females. This is an important result because usually only three to four age classes have been reported by analysing annual length-frequency data. Males and females were recruited to the fishery at 19.7 and 18.8 mm carapace length (CL) respectively. The von Bertalanffy growth parameters were estimated as K = 0.151 yr-1 and CL?= 52.8 mm for males, and K = 0.174 yr-1 and CL?= = 45.60 mm for females. Males reached larger sizes than females, which is in agreement with the growth of other Galatheids.
Does pleopod setation provide a measure of maturity in female southern rock lobsters Jasus edwardsii?
Authors: Gardner Caleb , Mills David , Frusher Stewart
Published: October 2008

Processes affecting the estimation of the size at onset of maturity (SOM) using ovigerous setae were investigated in southern rock lobsters Jasus edwardsii. Comparison of estimates of SOM based on ovigerous setae in samples collected during summer months (December-March) with those based on the presence of external eggs from winter months (June-August) indicated that ovigerous setae provide an accurate classification of maturity. Females with partially developed setation on pleopods are frequently observed in research catch-sampling projects and their maturity status was unclear. Our results show that these females with partially developed setae are most appropriately classed as immature, based on comparison between estimates of SOM determined by presence of external eggs or setae. The seasonal timing of field sampling affected estimates of SOM based on ovigerous setae, though tag-recapture data indicated that this was not associated with a loss of setae during a second annual moult. Estimates of SOM for populations of Jasus edwardsii around Tasmania can be based on maturity classification using ovigerous setae but care should be taken to ensure that seasonal timing of sampling is consistent.
Bycatch of the pelagic ray Dasyatis violacea in Uruguayan longline fisheries and aspects of distribution in the southwestern Atlantic
Authors: Domingo Andrés , Menni Roberto C. , Forselledo Rodrigo
Published: October 2008

The presence of the pelagic ray Dasyatis violacea (Bonaparte, 1832) in Uruguayan waters has been monitored since April 1998, the beginning of the National Observer Programme on board the Uruguayan tuna fleet (PNOFA). These are the first records of these species for the South Atlantic off Uruguay. Its distribution within the area is analysed, based on 13 trips made from April 1998 to September 2001 from 26 to 37°S. Five hundred and twenty five specimens were caught during this period. The presence of the species appears to be closely associated with the highest values of surface water temperature, with CPUE being relatively low below 20°C. The southern border of its distribution is around 36°S. Dasyatis violacea is part of a well-defined warm water fauna that reaches Uruguayan and northern Argentinean waters following warm subtropical waters. The incidental capture of D. violacea in the area reaches significant levels; the species is always discarded. We suggest that this bycatch is important and should be monitored from a conservation point of view.
Nanoplankton protists from the western Mediterranean Sea. II. Cryptomonads (Cryptophyceae = Crptomonadea)
Authors: Novarino Gianfranco
Published: October 2008

This paper is an electron microscopical account of cryptomonad flagellates (Cryptophyceae = Cryptomonadea) in the plankton of the western Mediterranean Sea. Bottle samples collected during the spring-summer of 1998 in the Sea of Alboran and Barcelona coastal waters contained a total of eleven photosynthetic species: Chroomonas (sensu auctorum) sp., Cryptochloris sp., 3 species of Hemiselmis, 3 species of Plagioselmis including Plagioselmis nordica stat. nov/sp. nov., Rhinomonas reticulata (Lucas) Novarino, Teleaulax acuta (Butcher) Hill, and Teleaulax amphioxeia (Conrad) Hill. Identification was based largely on cell surface features, as revealed by scanning electron microscopy (SEM). Cells were either dispersed in the water-column or associated with suspended particulate matter (SPM). Plagioselmis prolonga was the most common species both in the water-column and in association with SPM, suggesting that it might be a key primary producer of carbon. Taxonomic keys are given based on SEM.
Cnidae variability in Balanophyllia europaea and B. regia (Scleractinia: Dendrophylliidae) in the NE Atlantic and Mediterranean Sea
Authors: Terrón-Singler Alejandro , López-González Pablo J.
Published: October 2008

Traditionally and for practical reasons, skeleton structure has been the main source of taxonomic characters for scleractinian systematics, whereas information from soft tissues has been comparatively neglected. However, skeleton variability may leave species identification uncertain. The use of characters from soft tissues (e.g. polyp anatomy, cnidae size) is routine in the study of other (“soft”) hexacorallian orders. This contribution aims to determine whether cnidae characters are useful in taxonomic studies of scleractinians. The cnidae composition of two congeneric species—Balanophyllia europaea (Risso, 1826) and Balanophyllia regia Gosse, 1860 have been studied throughout a wide geographical area. The data obtained show consistent qualitative and quantitative differences between the two species. This study shows that the cnidae characters can be useful taxonomic criteria for distinguishing congeneric species.
Size structure of the planktonic community in microcosms with different levels of turbulence
Authors: Cózar Andrés , Echevarría Fidel
Published: October 2008

The evolution of a natural plankton community in two microcosms with well-differentiated turbulence levels (10-3 W m-3 and 10-1 W m-3) was compared during artificially-generated blooms. Biomass-size spectra were used to assess the effects of the turbulent kinetic energy (TKE) on the plankton community. Picoplankton was the size range least affected. Indirect effects on picoplankton size structure were related to the TKE effects on the predators. Small nanoplankton represented a transitional size range in which small and variable TKE effects were observed. In the diatom size range, the positive TKE effect on these non-swimmers increased progressively with cell size. The results showed that TKE has a combined effect on both biomass and size structure because of the linkage between these community characteristics. On the whole, the changes observed in the community size structure would lead to the uptake of the maximum available free energy.
Habitat use by the pearly razorfish, Xyrichtys novacula (Pisces: Labridae)
Authors: Katsanevakis Stelios
Published: October 2008

The population density of the pearly razorfish, Xyrichtys novacula, was estimated in eastern Mediterranean areas and was related to specific environmental variables, laying emphasis on the sediment granulometry. The density of X. novacula ranged from 0 to 20.0 individuals per 1000 m2. No correlation between X. novacula density and season, depth or the presence of common prey species was found. The X. novacula density was significantly correlated to the granulometry of the sediment, specifically to the median grain diameter Md? and the quartile deviation QD?, according to the model Density1/4 = 1.626 – 0.354Md? – 0.491QD?. The highest X. novacula densities occur in moderately or well sorted, coarse or very coarse sand. The density and distribution of X. novacula seem to largely depend on the sediment characteristics, due to the sand-diving behaviour of the species that necessitates the existence of appropriate substrate. Evidence is presented against the reported theory that during the cold season the species spends most of the time buried in the sand.
Age and growth of round sardinella (Sardinella aurita) in the northeastern Mediterranean
Authors: Tsikliras Athanassios C. , Koutrakis Emmanuil T. , Stergiou Konstantinos I.
Published: October 2008

The round sardinella, Sardinella aurita Valenciennes, 1847, was sampled monthly from commercial purse-seine vessels in Kavala Gulf (northern Aegean Sea, Greece) for two complete year cycles (September 2000-August 2002). Its maximum total length and age were 248 mm and 5 years respectively. The length-weight relationship was W=0.0062TL3.064 for males and W=0.0059TL3.084 for females. The marginal increment analysis on scales (n=1352) confirmed annulus formation during February-March, which coincided with the lowest sea surface temperature prevailing in the study area. The marginal increment ratio for ages 1, 2 and 3 was positively correlated with sea surface temperature (all r >0.4, P< 0.05). The parameters of the von Bertalanffy growth equation were: L?=248.678 mm, K=0.509 yr-1 and t0=-0.881 yr. The comparison of growth parameters for round sardinella, using the auximetric plot, from Mediterranean and northwest African waters indicated different growth patterns between the two areas.
Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during summer of 2001
Authors: Loureiro Sofia , Newton Alice , Icely John D.
Published: October 2008

Microplankton community, production, and respiration were studied alongside physical and chemical conditions at Sagres (SW Portugal) during the upwelling season, from May to September 2001. The sampling station was 5 km east of the upwelling centre off Cabo S. Vicente, and 2 km west of an offshore installation for bivalve aquaculture. Three major periods were distinguished according to sea surface temperature (SST): period 1 (P1; May and June), characterised by high temperature values (17.0±1.8°C); period 2 (P2; July), characterised by lower temperatures (14.6±0.3°C), identified as an upwelling-blooming stage; and period 3 (P3; August), characterised by a high temperature pattern (16.25±1.14°C). Chaetoceros spp., Thalassiosira spp., Lauderia spp., Detonula spp. and Pseudo-nitzschia spp. were the major taxa contributing to the dissimilarities between P2 (July) and the other periods. In July (P2), the average gross production (GP; 52.5±12.3 µM O2 d-1) and net community production (NCP; 46.9±15.3 µM O2 d-1)) peaked with the maximal concentrations of diatom-chl a. Dark community respiration (DCR) remained low and more constant throughout (4.6±3.6 µM O2 d-1). The plankton assemblage was dominated by diatoms throughout the survey. Physical events were the primary factors determining the microplankton structure and distribution at this location.
First report of a species of Prasiola (Chlorophyta: Prasiolacea) from the Mediterranean Sea (Lagoon of Venice)
Authors: Motti Chiara , Curiel Daniele , Rismondo Andrea , Bellemo Giorgio , Dri Chiara , Checchin Emiliano , Marzocchi Mara
Published: October 2008

A green alga belonging to the genus Prasiola, known from terrestrial, marine and freshwater habitats of polar and cold-temperate regions, is recorded for the first time in the Mediterranean Sea. In 2002, during a survey on soft substrata in the Lagoon of Venice (Italy), specimens referable to this genus were found in several areas. The morphological features of thalli are described and their occurrence in the Lagoon of Venice is discussed. Data on associated algal vegetation are also presented.
Age, growth, mortality, reproduction and feeding habits of the striped seabream, Lithognathus mormyrus (Pisces: Sparidae) in the coastal waters of the Thracian Sea, Greece
Authors: Kallianiotis Argyris , Torre Michele , Argyri Anna
Published: October 2008

Age, growth, mortality, reproduction and feeding habits were analysed for Lithognathus mormyrus collected in the coastal waters of the Thracian Sea from November 1997 to September 1999. Specimens ranged from 42 to 341 mm in total length. Weight increased with size allometrically (b = 3.242) for immature individuals and isometrically (b = 2.960) for males, females and intersexuals. Growth was described by the standard form of the von Bertalanffy growth equation and the estimated parameters were k = 0.21, t0 = –0.996 and L? = 309.4. Total and natural instantaneous rate of mortality was found to be Z = 0.79 year-1 and M = 0.61 year-1. Sex inversion occurred mainly between 210 and 300 mm (4-9 age classes). Males reached sexual maturity at 162.1 mm (2.5 years) and females at 190.40 mm (3.6 years). The spawning period occurred from May to September, while the gamete emission peaked in June-August. Stomach content analysis revealed that L. mormyrus is a carnivorous species feeding on benthic invertebrates, mainly polychaeta and bivalve molluscs. Ontogenetic variation in the diet composition showed that while growing, the fish become more generalist feeders. We also found that in the summer season the fish become more selective feeders.
Feeding ecology of Bathyraja macloviana (Rajiformes, Arhynchobatidae): a polychaete-feeding skate from the South-west Atlantic
Authors: Mabragaña Ezequiel , Giberto Diego Agustín , Bremec Claudia Silvia
Published: October 2008

The present paper analyses the diet, feeding strategy and niche width of B. macloviana in a sector of the Argentinean Continental Shelf (ACS). Individuals (n = 147) were collected from 43 sampling stations in late summer and autumn 2001. Thirty one alimentary items in the gut contents were found, with a clear dominance of polychaetes. Crustaceans were secondary alimentary items. The polychaete Travisia kerguelensis was the main food item ingested, followed by Nepthyidae, Sabellidae and Lumbrineridae, while Gammaridae and Cirolanidae were the main items among crustaceans. The niche width and feeding strategy displayed by B. macloviana support the specialisation towards polychaetes throughout this study. Slow motile and infaunal species constitute major preys. The results suggest that this skate actively selects worms, reflecting, in some sense, the composition of the polychaete assemblage, and allowing a low dietary overlap with other sympatric skates of the ACS.
Observations and trends on the intra-annual variation of the fish assemblages on two artificial reefs in Algarve coastal waters (southern Portugal)
Authors: Neves dos Santos Miguel , Monteiro Carlos C. , Lasserre Gerard
Published: October 2008

In 1990 two artificial reefs were deployed in southern Portuguese coastal waters, off Faro (FPR) and Olhão (OPR) respectively. In order to investigate the fish assemblages and their intra-annual variability, the two artificial reefs were monitored monthly by means of visual censuses from March 1994 to February 1995. Due to the complexity of the reefs, three strata were considered for fish counts. The two artificial reefs showed similar patterns in terms of residence status and spatial occupation. Most species recorded are characteristic of the infralittoral, the Sparidae family being the most represented. OPR, which is located closer to the main openings of the Ria Formosa lagoon, showed higher mean values than FPR in terms of: fish density (2.01±0.74 fish/m3)), fish biomass (123.6±77.4 g/m3) and number of species (7.5). The effect of the juvenile fish migrations from the lagoon to the coastal waters was more evident at OPR. FPR showed a greater intra-annual variation of the ecological indexes than OPR. The results show that artificial reefs that are equal in terms of complexity and size may aggregate different fish assemblages as a result of their isolation and the influence of both hydrological features (e.g. water temperature) and endogenous biological processes in the area (e.g. proximity of nursery grounds).
A new sponge-associated species, Syllis mayeri n. sp.(Polychaeta: Syllidae), with a discussion on the status of S. armillaris (Müller, 1776)
Authors: Musco Luigi , Giangrande Adriana
Published: October 2008

In the framework of a study carried out along the Belizean coasts, a new species of syllid, Syllis mayeri n. sp., was found harboured by the sponge Ircinia strobilina. The description of this new taxon is given, and compared to other similar congeneric species and to some Mediterranean material from the southern Italian coast ascribed to S. armillaris. The new species is characterized by some stout compound chaetae with ypsiloid appearance, whose probable use for attaching to the host is hypothesized. Other diagnostic features are antennae, tentacular cirri and dorsal cirri of the anterior portion of the body that are longer than in similar, compared species. Moreover, the mid-body dorsal cirri are typically spindle-shaped. A discussion on the status of some sponge-associated taxa from tropical and subtropical seas attributed to the so-called cosmopolitan S. armillaris is also given.
Spatial and temporal variation of natural toxicity in cnidarians, bryozoans and tunicates in Mediterranean caves
Authors: Martí Ruth , Uriz Maria J. , Turon Xavier
Published: October 2008

The natural toxicity of cnidarians, bryozoans and tunicates in two caves was assessed using the Microtox® technique in spring and autumn. One cave was located in the Cabrera Archipelago (Balearic Islands) and the other in the Medes Islands (Catalan littoral). The organisms analysed were good representatives of the coverage of each Phylum in the communities; however, these Phyla are less abundant than sponges which are the dominant group in these caves. Seventy-one percent of the species of cnidarians and bryozoans analysed were toxic in one of the caves, communities or seasons, which indicates the relevance of bioactive species in these groups. The tunicate Lissoclinum perforatum was the most toxic species. Although all three Phyla had some highly toxic species, a common pattern that related the caves, communities and seasons was not found. Seasonal variation of toxicity in cnidarians and bryozoans was higher in the Cabrera than in the Medes cave. Moreover, variation in toxicity either between communities or between seasons was a common trait for most cnidarians and bryozoans, whereas tunicates remained toxic throughout communities and seasons.
Phylogenetic analysis of flatfish (Order Pleuronectiformes) based on mitochondrial 16s rDNA sequences
Authors: Pardo Belén G. , Machordom Annie , Foresti Fausto , Porto-Foresti Fábio , Azevedo Marisa F. C. , Bañon Rafael , Sánchez Laura , Martínez Paulino
Published: October 2008

The phylogenetic relationships of the order Pleuronectiformes are controversial and at some crucial points remain unresolved. To date most phylogenetic studies on this order have been based on morpho-anatomical criteria, whereas only a few sequence comparisons based studies have been reported. In the present study, the phylogenetic relationships of 30 flatfish species pertaining to seven different families were examined by sequence analysis of the first half of the 16S mitochondrial DNA gene. The results obtained did not support percoids as the sister group of pleuronectiforms. The monophyletic origin of most families analyzed, Soleidae, Scophthalmidae, Achiridae, Pleuronectidae and Bothidae, was strongly supported, except for Paralichthyidae which was clearly subdivided into two groups, one of them associated with high confidence to Pleuronectidae. The analysis of the 16S rRNA gene also suggested the monophyly of Pleuronectiforms as the most probable hypothesis and consistently supported some major interfamily groupings.
Intercomparing drifts from RAFOS and profiling floats in the deep western boundary current along the Mid-Atlantic Ridge
Authors: Machín Francisco , Send Uwe , Zenk Walter
Published: October 2008

The Lagrangian nature of cycling floats is evaluated in the framework defined by the Deep Western Boundary Current of the Mid-Atlantic Ridge. In a statistical approach, speeds and drifts are estimated for an APEX cycling float and compared with the velocities inferred from a park ensemble of four eddy-resolving RAFOS floats. They were deployed at the same location and ballasted for drifting at the same mission depth. Displacement errors induced by geostrophic shear and wind forced currents are analyzed. We observe that the velocity estimated from the RAFOS floats is not statistically different from the velocity estimated from the APEX float. Likewise, the initial separation between the cycling float and a simultaneously deployed RAFOS float has been studied in terms of the turbulent diffusivity. Though the performance of this study in comparable cases without a mean current field may be limited, these oceanic observations support exploiting the Lagrangian nature of the cycling floats.
Comparative morphometrics of two populations of Mugil curema (Pisces: Mugilidae) on the Atlantic and Mexican Pacific coasts
Authors: Ibáñez-Aguirre Ana Laura , Cabral-Solís Esther , Gallardo-Cabello Manuel , Espino-Barr Elaine
Published: October 2008

A population of Mugil curema in the Gulf of Mexico was compared with one in the Pacific Ocean using nine morphometric variables. The allometries of each measurement were estimated in relation to total length. Morphometric variations were analyzed using the normalization of the individuals of each group and two multivariate methods: correspondence analysis, used to explore the information, and discriminant analysis. Results indicated that the diameter of the eye differentiated the populations of both coasts, the Atlantic population showed a larger eye diameter. However, other than this and the body width (which can be strongly influenced by sexual maturation) there was no difference between the shapes of both populations. We discuss the larger morphometric variability of the Atlantic population which may be due to the presence of more than one population unlike the Pacific population.
Look for Margalef's written contributions
Authors: Peters Francesc
Published: October 2008

No available
Morphology and rDNA phylogeny of a Mediterranean Coolia monotis (Dinophyceae) strain from Greece
Authors: Dolapsakis Nicolas P. , Kilpatrick Michael W. , Economou-Amilli Athena , Tafas Triantafyllos
Published: October 2008

Sequences of LSU and SSU ribosomal RNA genes and phylogeny have not been widely investigated for the dinoflagellate Coolia monotis Meunier, and no information is available on the small and large rDNA subunits of Mediterranean strains. A strain isolated from the Thermaikos Gulf in northern Greece was identified as C. monotis—a new record for the Greek algal flora—using thecal morphology by light, epifluorescence and scanning electron microscopy. The small subunit and partial (D1/D2) large subunit sequences were analyzed and compared to other strains of C. monotis and dinoflagellates from various regions. Thecal architecture showed that the Greek strain of C. monotis was phenotypically similar, but not identical, to other strains reported in literature. The partial LSU sequence (700 bp) was found to vary by 113 bp positions (16%) from the C. monotis strain from New Zealand, whereas the SSU (1757 bp) had 15 bp differences (0.85%) from the strain from Norway. Phylogenetic tree construction showed that the Greek strain fell within the Coolia clade and had a close relationship with the families Ostreopsidaceae and Goniodomaceae of the order Gonyaulacales. Preliminary findings suggest the existence of different genotype strains of C. monotis with large intraspecific genetic variability and minimal morphological differentiation (similar phenotypes). Certain ecological and evolutionary implications of these findings are discussed.
Trophic categorization in the Rías Baixas (NW Spain): nutrients in water and in macroalgae
Authors: Villares Rubén , Carballeira Alejo
Published: October 2008

Marine eutrophication caused by an excess supply of nutrients is a serious problem in many coastal areas throughout the world. In the present study we used the capacity of macroalgae (Ulva and Enteromorpha) to integrate the nutrient regime of a water body in order to examine the trophic categorization in the embayments studied. We found that the trophic categorization established based on nutrient levels in macroalgae differed from that established based on concentrations in the water. The waters of the innermost areas of the inlets were the most nutrient enriched; the algae appeared to be more affected by specific local conditions and did not display the gradient of decreasing nutrient concentrations from inner to outer areas that was observed in the water samples. The lack of correspondence between nutrients in the water and in the algae in the present study may have been due to the heterogeneous nutrient conditions found in coastal areas, so that the intertidal algae did not adequately reflect the nutrient levels of the inner zones of the embayments under study.
Analysis of wind events in a coastal area: a tool for assessing turbulence variability for studies on plankton
Authors: Guadayol Òscar , Peters Francesc
Published: October 2008

Turbulence at different scales, from generation to dissipation, influences planktonic communities. Many experimental studies have recently been done to determine the effects of small-scale turbulence on plankton, but it is difficult to state the relevance of the findings since there is little unbiased information on turbulence variability in the sea. In this study, we use wind velocity data series from several meteorological stations located along the Catalan coast to estimate the spatial and temporal variability of small-scale turbulence in the upper ocean. Using a peaks-over-threshold approach, we develop a statistical model to assess the frequency of wind events as a function of their persistence and intensity. Finally, the wind speed data series are converted into turbulent energy dissipation rate estimates at 1 m depth to determine the general distribution of turbulence on the Catalan coast. Geographical variability is larger than seasonal variability in frequency and persistence of wind events, owing to differences in local relief. These statistical models developed for wind events combined with empirical relationships between wind and turbulence, are tools for estimating the occurrence and persistence of turbulent events at a given location and season. They serve to put into context the past, present and future studies of the effects of turbulence on coastal planktonic organisms and processes.
Updated checklist and identification of areas of endemism of benthic amphipods (Caprellidea and Gammaridea) from offshore habitats in the SW Gulf of Mexico
Authors: Winfield Ignacio , Escobar-Briones Elva , Morrone Juan J.
Published: October 2008

An updated checklist of the benthic amphipods associated with soft bottoms in the SW Gulf of Mexico has been made and the areas of endemism have been identified. Amphipods were collected in a depth interval of 25 to 3700 m during six cruises from 1994 to 1999. A total number of 56 species were identified, 11 belonging to the suborder Caprellidea and 45 to the suborder Gammaridea. Thirteen species extended their geographical distribution within the Gulf of Mexico and four species were considered new records in the Gulf of Mexico. A biogeographic analysis based on the shared species and the parsimony criterion helped identify three areas of endemism in the SW Gulf of Mexico. They were named: area A, a small area on the continental shelf of the Bay of Campeche; area B, the continental slope of the Bay of Campeche; and area C, the lower continental slope of the Mexican ridges extending into the western Sigsbee abyssal plain. These areas are defined in terms of their complex topography that may help isolate habitats that promote endemicity.
Foraminiferal assemblages in the Ubatuba Bay, south-eastern Brazilian Coast
Authors: Burone Leticia , Pires-Vanin Ana Maria S.
Published: October 2008

Live benthic foraminifera assemblages were studied in 40 surface sediment samples collected in the Ubatuba Bay (northern coast of São Paulo State) in order to investigate the relationship between the geological, physicochemical parameters and the ecological data. The area has significant contributions of terrestrial inputs from four rivers that flow into the bay. Biological data were analyzed with multivariate techniques of cluster analysis and a Principal Component Analysis (PCA) was carried out for abiotic factors. The Suborder Rotaliina was dominant in the whole studied area. The result of the cluster analysis allowed us to recognize three groups of stations corresponding to three foraminifera assemblages and different environment conditions. The PCA revealed approximately the same three groups obtained with the cluster analysis. A slight increase in diversity in the outer bay was measured. The inner environment is dominated by A. tepida, evidencing local instabilities. Infaunal species are distributed in the middle region associated with mud and a high content of organic matter, while the most external region has similar percentages of epifaunal and infaunal, which indicates the higher energy condition in this portion of the bay. We also quantified the abnormal specimens that were mainly present in the inner bay, especially represented by A. tepida specimens.
Observations on the ontogenetic and intraspecific changes in the radula of Polycera aurantiomarginata García and Bobo, 1984 (Gastropoda Opisthobranchia ) from Southern Spain
Authors: Martínez-Pita Inés , Guerra-García Jose M. , Sánchez-España Ana I. , García Francisco J.
Published: October 2008

Polycera aurantiomarginata García and Bobo 1984 has a stable population in the intertidal area of El Portil beach (Huelva, SW Spain). This fact allowed specimens of different sizes to be collected from March 2001 to December 2003. In this paper, the ontogenetic variations of the radula of P. aurantiomarginata are studied. The radulae of 141 specimens were examined, 138 from El Portil and 3 from La Herradura (Granada, SE Spain). Specimens of 1.5-2 mm in length lack the typical radula described for P. aurantiomarginata. They have the so called pre-radula whose teeth are different in size and shape from the typical radula of the adults. In the specimens of 3 and 4 mm the pre-radula coexists with the characteristic radula, which is the single structure present in the specimens larger than 4 mm. The following features of the radula are included in this study: radular length, number of teeth rows and length of the outer lateral teeth. According to the three measured variables, the affinities among specimens without a pre-radula were established through cluster analysis, which defined three different groups (4-10 mm, 11-22 mm and 23-48 mm). Correlations between specimen length and radula length, number of rows and mean length of outer lateral teeth were significant. Feeding strategies could be related to the different morphology of the radula established by the Cluster analysis.
Protection of the goose barnacle Pollicipes pollicipes, Gmelin, 1790 population: the Gaztelugatxe Marine Reserve (Basque Country, northern Spain)
Authors: Borja Ángel , Muxika Iñigo , Bald Juan
Published: October 2008

Marine protected areas are expected to play a prominent role in the conservation of marine resources and fisheries management. In the Basque Country (northern Spain) the small Marine Reserve of Gaztelugatxe (158 ha) was established in 1998. One of the aspects taken into account in protecting this area was the overexploitation of the goose barnacle Pollicipes pollicipes. Now, after five years of protection, differences in density, biomass, size and weight of the goose barnacle are investigated inside the protected area (Aketze and Gaztelugatxe locations) and outside of it, at the nearest locations (Izaro and Ogoño) which have been continuously exploited. This contribution demonstrates that the reserve could be an efficient tool in preserving the goose barnacle populations in the area. Hence, density, biomass and allometric coefficients are higher in the protected areas. These locations are also associated with higher percentages of juveniles, together with a high number of large-sized individuals.
Diel and vertical movements of preflexion fish larvae assemblage associated with Posidonia oceanica beds
Authors: Del Pilar Ruso Yoana , Bayle-Sempere Just T.
Published: October 2008

Habitat complexity is a strong determinant of fish assemblage structure. Enhanced food resources and protection from predators are generally considered the main benefits of vegetated areas. We investigated the diel and vertical movements of preflexion fish larvae within and above the leaf canopy of Posidonia oceanica to determine if it acts as an important habitat for larval stage fish. Samples were taken with moored plankton nets during the night and day at two depths (13 and 15 m) over five consecutive days in July 2000 in the Marine Protected Area off Tabarca Island (Spain, SW Mediterranean Sea). In total, 353 fish larvae were captured. The most abundant taxa were Sardinella aurita, Sparidae, Engraulis encrasicolus and Gobiidae. Sparidae were more abundant within the leaf canopy during the day but increased in waters 2 m above the canopy at night. In contrast, Sardinella aurita were present throughout the entire water column during both the day and night. We conclude that the P. oceanica leaf canopy is important as a transitional shelter for the early stage larvae of some demersal fish species.
Recovery of Cymodocea nodosa (Ucria) Ascherson photosynthesis after a four-month dark period
Authors: Malta Erik-Jan , Brun Fernando G. , Vergara Juan J. , Hernández Ignacio , Pérez-Lloréns J. Lucas
Published: October 2008

P align=justify>Cymodocea nodosa plants were dark incubated for four months. The potential of reactivating photosynthesis was tested in an experiment in which half of the plants were reilluminated (HL) while the other half were grown under very low irradiance levels (LL). Photosynthesis was measured using PAM fluorescence and tissue nutrient and carbohydrate contents were analysed. Photosynthetic efficiency (Fv/Fm) in HL plants increased from 0 to 0.58, whereas LL plants remained inactive. Photosynthetic parameters also increased, resulting in a final Ik of 97.5 µmol m-2 s-1. Leaf shedding led to a negative mean RGR in HL plants. Tissue C and N dropped considerably during dark incubation in both rhizomes and shoots. Starch content was nearly equal for rhizomes and shoots (4.3 mg /g DW) and was not affected by dark incubation. In contrast, sucrose content dropped from 40.0 mg /g DW to zero in shoots and from 240 to 40.0 mg /g DW in rhizomes in HL plants. We conclude that C. nodosa is capable of recovering photosynthetic activity after four months darkness, which is considerably longer than the 80 d recorded so far for a seagrass. Stored carbohydrates, more specifically sucrose, play an important role in both survival and reactivation.
Habitat selection by grey mullets (Osteichthyes: Mugilidae) in Mediterranean estuaries: the role of salinity
Authors: Cardona Luis
Published: October 2008

A stratified study of microhabitat use by grey mullet on the island of Minorca (Balearic archipelago, western Mediterranean) showed that the distribution of all the species was dramatically affected by salinity. Sites with a salinity level under 15 were positively selected in spring and summer by those species whose growth performance was the best in oligomesohaline water (Liza ramado and Mugil cephalus) but also by a species whose growth was not affected by salinity (Chelon labrosus). Liza aurata concentrated in polyhaline and euhaline sites, where growth was improved, a pattern also exhibited by Liza saliens. Both species avoided fresh water sites all year round. As a consequence, community structure was correlated with salinity. The above reported electivity patterns often disappeared in autumn, when most grey mullets migrate off-shore.
Juvenile European anchovy otolith microstructure
Authors: Cermeño Pablo , Morales-Nin Beatriz , Uriarte Andrés
Published: October 2008

Juvenile European anchovy (Engraulis encrasicolus) has a complex incremental growth pattern that was studied using scanning electron microscope (SEM) and optical microscope observations. Daily increments were identified and related to rhythmic growth patterns while double-band structures were identified as one increment. The causes of these growth patterns are discussed.
First evidences of Acartia bifilosa resting eggs in sediments of the Urdaibai estuary (Bay of Biscay): abundance and hatching success
Authors: Uriarte Ibon , Villate Fernando
Published: October 2008

The abundance and hatching success of Acartia bifilosa resting eggs in subtidal sediments of the Urdaibai estuary was analysed in the context of a study on the spatial and temporal dynamics of this species. Two sediment cores of 20 to 30 cm depth were obtained at two sites of the middle zone, where the accumulation of mud and organic particles is favoured. Laboratory incubations were performed to determine the hatching success of eggs and identify newborns. Resting egg abundance was around 107 eggs m-2, and was higher at the site where the A. bifilosa population maintains an optimal position in the water column. The lower egg abundance in upper layers, as corresponds to winter, was associated with the seasonal dynamics of planktonic populations. On average, the hatching success was >50% at both sites. The lack of significant differences in the hatching success according to sediment depth suggests that eggs remain viable after being buried for a long-time in anoxic conditions. This enables us to infer that the benthic egg bank of A. bifilosa in this estuary is a safe source of recruits into the planktonic population, and plays a crucial role in recuperationand maintenance of the population.
Age structure, growth and mortality of the striped goby, Gobius vittatus (Gobiidae) in the northern Adriatic Sea
Authors: Kovacic Marcelo
Published: October 2008

The striped goby, Gobius vittatus Vinciguerra, 1883 is a Mediterranean gobiid species considered to be rare with very little data on its biology and ecology. A sample of 704 specimens of G. vittatus was collected by SCUBA diving at three locations in the northern Adriatic Sea (Kvarner area) from April 2001 to March 2002. The present paper provides the first information on age structure, lifespan, growth and mortality of G. vittatus. The size range of individuals was between 19.2 and 54.0 mm. The maximum estimated age was 4 and 3 years for females and males respectively. The total mortality rate (Z) was estimated to be from 0.94 to 1.08 for females and from 0.99 to 1.43 for males. The von Bertalanffy growth parameters estimated from the mean monthly age-length data were significantly different between sexes (females: L∞ = 50.96, K = 1.02 and t0 = -0.47; males: L∞ = 50.13, K = 1.18 and t0 = -0.42).
Physical properties and their relationship to sedimentary processes and texture in sediments from mud volcanoes in the Anaximander Mountains (Eastern Mediterranean)
Authors: Casas David , Ercilla Gemma , Lykousis Vasilis , Ioakim Chryssanthi , Perissoratis Constantine
Published: October 2008

This research focuses on the mud volcanoes Amsterdam, Kazan and Kula located in the Anaximander Mountains (SW Turkey continental margin), which are characterized by the presence of sediments containing gas and gas hydrate. These mud volcanoes were sampled by recovering four gravity cores. For sediment located right on top (crater or active part of the summit) of the mud volcanoes, the physical properties are controlled by lithology and mud volcanic processes rather than the degree of compaction. This could suggest the possibility of current mud volcanic activity. In contrast, the sediment located in the external flank of Kula mud volcano displays physical properties mostly related to consolidation effects and to the type of sediment at a detailed scale, as occurs typically in deep-sea fine grained sediments. This suggests a restricted influence of mud volcanic processes.