bluuebunny/crossref_metadata_2025 huggingface dataset:
Pollution influence on bacterial abundance and chlorophyll-a concentration: case study at Idku Lagoon, Egypt
Authors: Siam E. , Ghobrial M.
Published: October 2008

Idku lagoon is one of the northern delta lakes, connected with the Mediterranean Sea through Boughaz El Maadyah. It is subjected to industrial, domestic and agricultural pollution. Depending on collected data of water samples during one year of research, the lagoon was separated into different water masses by using the discriminant function analysis (DFA). Estimation of some biological (total and saprophytic bacteria, faecal bacteria and chlorophyll-a) and chemical variables (chlorosity, organic matter, dissolved oxygen and dissolved inorganic nutrients) lead to differentiate Idku lagoon waters into four sites: Drain (I), Lake Proper (II), Bay (III) and Boughaz (IV). The highly effective parameters for the predicted sites were chlorosity, organic matter and faecal bacteria (E. coli). Factor analysis was applied for each site to find out the correlating variables (biological and chemical) that seemed to control each independent site. At Drain site (I) pollution by agricultural sewage (through Idku Drain) supported bacterial as well as algal growth, while at Lake Proper site (II) bacteria seemed to obtain their nutrient supply from algal origin after their death and lysis. Site II was characterized by its absolute highest chlorophyll-a content. Factor models for sites II and III indicated a positive and mutual relationship between bacterial microbiota and chlorophyll-a. The strong correlation that appeared between all biota from factor model for site III, at the absolutely high chlorosity values (compared to the other sites), could be due to the development of salt tolerant strains and species. Factor model for site IV revealed a strong positive correlation between bacterial microbiota and nutrients (derived from industrial pollution at Boughaz El Maadyah), but negatively correlated to chlorophyll-a. Thus it seemed that bacteria obtained their nutrient supply mostly from sewage.
First record of Holocentrus ascensionis (Osbeck, 1765) (Osteichthyes: Holocentridae) in the Canary Islands (Central-east Atlantic)
Authors: Castro-Hernández José J. , Martín-Gutiérrez Ana Y.
Published: October 2008

The capture of a specimen of Holocentrus ascensionis (Osbeck, 1765), a species previously unrecorded in the Eastern Atlantic north of Gabon, is reported from Gran Canaria Island (Canary Islands, Central-East Atlantic).
Measurements of cnidae from sea anemones (Cnidaria: Actiniaria), III: ranges and other measures of statistical dispersion, their interrelations and taxonomic relevance
Authors: Williams R. B.
Published: October 2008

This is the third of a series of papers examining the taxonomic relevance of some statistical treatments of measurements of cnidae from sea anemones (Actiniaria). Some cnida lengths from fresh tissue samples (column ectoderm, tentacles or acontia) from Nematostella vectensis, Haliplanella lineata, Sagartia elegans, Metridium senile, Cereus pedunculatus, Sagartia troglodytes, Anthopleura thallia, Urticina eques and Sagartiogeton lacerates were measured. Five measures of statistical dispersion (sample standard deviation, coefficient of variation, observed sample range, standard range, and 99% probable maximum value of the standard range) were calculated, and their interrelations and potential applications were appraised. It has long been the convention to use the largest and smallest cnida sizes (observed sample range) from tissue samples in attempts to establish differences between actiniarian taxa. However, such data do not reflect the true extremes of a population range. In the present study, the 99% probable maximum value of the standard range for a standard abundance of 1,000 gave the greatest and, therefore, the most cautious estimate of a population range of cnida sizes for a species. This maximum standard range is the only measure of dispersion of cnida sizes that may be used validly to demonstrate that anemone specimens are of different species, and then only if there is no overlap between the extreme cnida sizes being compared. However, partial or complete overlaps of cnida size extremes do not necessarily indicate that specimens are conspecific; other taxonomic characters must also be considered. Coefficients of variation may provide valuable clues as to the homogeneity or heterogeneity of samples of cnida measurements. This paper should be read in conjunction with the first two in this series, which address the taxonomic relevance of differences between mean cnida sizes (Williams, 1996, Sci. Mar., 60: 339-351; 1998, Sci. Mar., 62: 361-372).
Fish larvae from the Canary region in autumn
Authors: Rodríguez J. M.
Published: October 2008

In this paper, the taxonomic composition of the fish larvae community in the Canary region in autumn 1991 is presented. In total, 8699 larvae belonging to 58 fish families were studied. 176 taxonomic groups were identified, 149 at species level and the rest were identified at a higher level. The most numerous family and the one that presented the greatest number of species was Myctophidae. The most frequently caught species was Cyclothone braueri. The taxonomic composition (at family level) of the fish larvae community, dominated by four mesopelagic families, was typical of oceanic regions of warm waters. The most remarkable feature of the fish larvae community was its high specific diversity.
Wind effect as forcing factor controlling distribution and diversity of copepods in a shallow temperate estuary (Solis Grande, Uruguay)
Authors: Gómez-Erache M. , Norbis W. , Bastreri D.
Published: October 2008

Spatial and temporal variations of planktonic copepods were investigated in relation to environmental conditions in the Solís Grande estuary (34°22´S, 55°33´W), Uruguay. Over a period of fifteen days, samples were taken daily at three stations along the main axis of the estuary, and the species composition and abundance were determined. The Solís Grande is a shallow estuary (2.0 m) with no vertical discontinuities. Comparisons of surface versus bottom hydrographic values indicated no vertical stratification of temperature and salinity during the studied period. The species-environmental relationships explain 63.6% of the system´s variability considering the two first axes from Redundance Analysis (RA). Copepods showed strong differences in distribution and abundance between stations and successive days. In the region the winds quickly rotate from sectors S-SE (frontal period) to E-NE (post-frontal period). Changes in abundance were significantly related to the inflow and outflow of water produced by the rotation of winds. At smaller space and time scales, the differences highlighted by the RA were the result of wind-forced hydrodynamics after the frontal period. In this situation hydrographic features were dominant (factor one of RA) and wind effects were of secondary importance (factor two of RA). Six species were identified and the estuary was clearly dominated by Acartia tonsa. The results showed two negatively correlated groups: one was integrated by Oithona nana, O. simplex, Paracalanus parvus and P. crassirostris while the second group was integrated by A. tonsa and Euterpina acutifrons. Environmental variability may be responsible for the low diversity.
Application of flow cytometry in marine phytoplankton research: current applications and future perspectives
Authors: Veldhuis Marcel J.W. , Kraay Gijsbert W.
Published: October 2008

A brief overview is given of current applications of flow cytometry (FCM) in marine phytoplankton research. This paper presents a selection of highlights and various technical and analytical problems we encountered during the past 10 years. In particular, the conversion of the relative values obtained in terms of size and fluorescence applying FCM to quantitative estimates of cell size, pigment concentration, genome size etc., is addressed. The introduction of DNA -cell-cycle analysis made easily assessable by flow cytometry has been of great importance, allowing in situ measurement of species specific growth rates. Key questions in ecology such as factors determining the wax and wane of phytoplankton bloom can now be better answered in terms of species specific growth and mortality. Finally, flow cytometry provides detailed information of the physiological status of the individual algal cells. New staining methods enable us to distinguish between viable and non-viable cells and so will help us to elucidate the importance of automortality in aquatic ecosystems.
Short-term variations of the vertical distribution of cyanobacteria in the open Mediterranean Sea
Authors: Denis Michel , Martin Valérie , Andersen Valérie
Published: October 2008

A general study of biogeochemical processes (DYNAPROC cruise, May 1995) was conducted at a station in the open northwestern Mediterranean Sea where horizontal advection was weak. During this experiment, short-term variations of the vertical distribution of cyanobacteria were investigated and a possible link with diel vertical migration was considered. Consistently, the experimental work was conducted at a time scale of a few hours. Cyanobacteria were the most abundant population in the pico- and nanoplankton size-class. Their vertical distribution was monitored over 36 h with a frequency of 4 h. With such a time resolution, they experienced a single grazing event during daytime and, at night, they were heavily grazed when the upper layers were occupied by organisms migrating from the aphotic zone. The corresponding integrated (0-90 m) losses of cyanobacteria during the night amounted to 534 mg C m-2. Though daytime grazing is most likely due to nanoflagellates and microzooplankton, night-time grazing could significantly involve migrant macrozooplankton organisms and sustain a periodic export of organic matter. This study stresses the importance of the potential export of organic matter as a consequence of the diel vertical migration, export that could not be accounted for by measurements at longer time scale.
Probing the physiological state of phytoplankton at the single-cell level
Authors: Jochem Frank J.
Published: October 2008

Probing the physiological state of phytoplankton at the single-cell level provides valuable insight in ecological studies as well as in environmental monitoring of pollution or UV impacts. This paper reviews the recent progress in assessing the physiological state of phytoplankton with flow cytometry by inherent cell properties such as cell size and chlorophyll autofluorescence, specific fluorescent dyes, and newly developed molecular probes and enzyme substrates. It is reported how nitrogen and iron limitation as well as the effect of copper pollution could be derived from changes in cell inherent properties. Effects of Cu were also recorded by monitoring cell membrane potentials and esterase activity. Photosynthetic capacity of algae was assessed by changes in chlorophyll fluorescence with the electron transport inhibitor DCMU, by a cytometric adaptation of the pump-and-probe approach, and molecular probes for Rubisco. Antibodies were also applied to mark non-terminal stages in the cell DNA replication cycle, to detect non-proliferating cells, to assess DNA damage caused by UV-B radiation and to quantify diatom stickiness. Fluorescein diacetate proved useful to discriminate metabolically active from inactive cells and to reveal strategies of dark survival in algae. The activity of alkaline phosphatase was recorded by a new fluorigenic substrate ELF, and polyclonal antibodies against nitrate reductase (NR) provided measurements of the NR abundance. An outlook will show how recent developments in molecular probes might affect the future analysis of marine ecosystems and their communities.
Using flow cytometry for counting natural planktonic bacteria and understanding the structure of planktonic bacterial communities
Authors: Gasol Josep M. , Del Giorgio Paul A.
Published: October 2008

Flow cytometry is rapidly becoming a routine methodology in aquatic microbial ecology. The combination of simple to use bench-top flow cytometers and highly fluorescent nucleic acid stains allows fast and easy determination of microbe abundance in the plankton of lakes and oceans. The different dyes and protocols used to stain and count planktonic bacteria as well as the equipment in use are reviewed, with special attention to some of the problems encountered in daily routine practice such as fixation, staining and absolute counting. One of the main advantages of flow cytometry over epifluorescence microscopy is the ability to obtain cell-specific measurements in large numbers of cells with limited effort. We discuss how this characteristic has been used for differentiating photosynthetic from non-photosynthetic prokaryotes, for measuring bacterial cell size and nucleic acid content, and for estimating the relative activity and physiological state of each cell. We also describe how some of the flow cytometrically obtained data can be used to characterize the role of microbes on carbon cycling in the aquatic environment and we prospect the likely avenues of progress in the study of planktonic prokaryotes through the use of flow cytometry.
Flow sorting in aquatic ecology
Authors: Reckermann Marcus
Published: October 2008

Flow sorting can be a very helpful tool in revealing phytoplankton and bacterial community structure and elaborating specific physiological parameters of isolated species. Droplet sorting has been the most common technique. Despite the high optical and hydro-dynamic stress for the cells to be sorted, many species grow in culture subsequent to sorting. To date, flow sorting has been applied to post-incubation separation in natural water samples to account for group-specific physiological parameters (radiotracer-uptake rates), to the production of clonal or non-clonal cultures from mixtures, to the isolaton of cell groups from natural assemblages for molecular analyses, and for taxonomic identification of sorted cells by microscopy. The application of cell sorting from natural water samples from the Wadden Sea, including different cryptophytes, cyanobacteria and diatoms, is shown, as well as the establishment of laboratory cultures from field samples. The optional use of a red laser to account for phycocyanine-rich cells is also discussed.
Fecundity of the squid Loligo vulgaris, Lamarck, 1798 (Myopsida, Loliginidae) off northwest Africa
Authors: Laptikhovsky V.
Published: October 2008

Egg dimensions were 2.0-2.2 x 1.5-1.6 mm. Potential fecundity (all oocyte stock) of mature female L. vulgaris was estimated as 28,500-74,200 oocytes, including 3,500-30,500 yolk oocytes, 1,300-8,000 of those were ripe eggs in the oviduct. Relative fecundity was 114-251 (mean 211.3, SD=48.7), the index of Potential Reproductive Investment was 0.29-0.71 (mean 0.566, SD=0.151). Ovary maturation was similar to that observed in other loliginid squid, when small protoplasmic oocytes predominate throughout the life cycle.
Sublittoral meiobenthic assemblages from disturbed and non-disturbed sediments in the Balearics
Authors: Deudero S. , Vincx M.
Published: October 2008

Qualitative and quantitative differences in species composition of meiobenthic communities illustrate the differences among various taxonomic assemblages in the Balearic Islands (Western Mediterranean) analysed by means of multivariate analysis. Average densities ranged between 1000 and 4000 ind?10cm-2, and are in the same range as previously reported from other shallow Mediterranean areas. The dominant meiofaunal taxa were Nematoda (range 40 to 75%), Turbellaria (5-47%) and Copepoda (2-14%), while other meiofaunal groups (Tardigrada and Rotifera) were only represented by approximately 5% of the total abundance. The dominant nematode families were Desmodoridae, Chromadoridae and Xyalidae. The meiofaunal communities showed little variation among locations. Moreover, small-scale heterogeneity does not seem to affect nematode distribution as shown by the high similarity between replicates in the multivariate analysis.
Continental contribution of suspended sediment to an estuary: Ría de Vigo
Authors: Pazos O. , Nombela M. A. , Vilas F.
Published: October 2008

Five rivers that flow into the Ría de Vigo were sampled during a period of 2 years from January 1995 to February 1997. Their catchment area approximates 45.3% of the total drainage into the Ría de Vigo. Flow rates and suspended matter (sm) data were recorded to calculate the volume of runoff. The mineralogy was studied using XRD. Three of the five rivers had been previously sampled during a period of one and a half years, from 1987 to 1989, permitting the comparison of data then and now. The results show low contributions of suspended matter from the rivers but that anthropogenic (land use and forest fires) factors have a direct influence on the increase of suspended matter. The mineralogy is very similar in all five rivers without any appreciable seasonal change, although an increase in the amount of gibbsite was found during periods of unusual erosion.
Oxygen consumption of the freshwater crab Elamenopsis kempi (Chopra and Das, 1930) from the Garmat-Ali river, Iraq
Authors: Ali Malik H. , Salman Salman D. , Al-Adhub Abdul Hussain Y.
Published: October 2008

The rate of oxygen consumption of the subtidal hymenosomatid crab Elamenopsis kempi, was studied from February 1988-December of the same year. The experiments were conducted by a Gilson respirometer over a wide temperature range (15-35°C), with the aim of estimating the individual oxygen consumption. Individual rate of oxygen consumption increased with increasing body mass at all temperatures for males, females and ovigerous females. The mean rate of oxygen consumption over the temperature range studied for the males varied from 1.20- 22.38 µl O2 ind-1 h-1, for the females from 2.05-20.73 and for the ovigerous females from 5.07-27.31 µl O2 ind-1 h-1. The metabolic rate of the males ranged from 0.130-0.63, of the females from 0.35-1.034 and of the ovigerous females from 0.309 -1.096 µ1 O2 mg-1 h-1.The overall Q10 value was 1.92. The males were thermally sensitive at 15-25°C and compensate at 20-30°C, whereas the females, both non-ovigerous and ovigerous were compensating at all temperatures.
Influence of the structure of Posidonia oceanica meadows modified by bottom trawling on crustacean assemblages: comparison of amphipods and decapods
Authors: Sánchez-Jerez P. , Barberá-Cebrian C. , Ramos-Esplá A. A.
Published: October 2008

The seagrass Posidonia oceanica plays an important role as habitat for invertebrates. A correlative study was done in El Campello (SE Spain) to understand the relationships between assemblage structure of crustaceans and modification of P. oceanica structure caused by bottom trawling. We compared the changes of community structure of the most important groups of crustaceans, amphipods and decapods with changes of cover, density, detritus and rhizome fragments. Sampling was carried out in four control and four impact locations, along a gradient of degradation (17 m depth, August 1992). Multivariate analysis was used for community data (nm-MDS) and P. oceanica structure (PCA). Both groups showed a similar number of species. The amphipod community showed a clear pattern of community changes with significant differences between impact and control locations (global R = 0.298, p
Climatological coupling of the thermohaline decadal changes in Central Water of the Eastern North Atlantic
Authors: Pérez F. F. , Pollard R. T. , Read J. F. , Valencia V. , Cabanas J. M. , Ríos A. F.
Published: October 2008

Data collected at 42ºN, 10ºW in the intergyre region of the Northeast Atlantic show significant year to year variability in the T-S characteristics of the upper 800m of the water column. Taking salinity values on the sq = 27.1 kg m-3 isopycnal as representative of the Eastern North Atlantic Central Water mass it was found that the variability correlates well with the wind stress at 43ºN, 11ºW, with cumulative river discharge (which we take as an index of precipitation over the ocean) and with the NAO (which is an index of the strength and position of storm tracks and the state of the evaporation-precipitation balance). The covariation illustrates the close coupling between water mass formation and climate in the North Atlantic, where climate changes affect the deep ventilation by which ENACW is formed and the evaporation-precipitation balance from which the T-S signature results. Hints of a 20 year cycle in the ocean correlate with a 20 year periodicity in the NAO. It remains to be established whether there is a feedback mechanism by which water mass anomalies affect the climate and the intensity and variation of the NAO pattern, and the extent to which upper ocean observations can be used as an indicator of future climate trends.
Contribution to the study of the morphology of the teeth of the nursehound Scyliorhinus stellaris (Chondrichthyes: Scyliorhinidae)
Authors: Soldo A. , Dulcic J. , Cetinic P.
Published: October 2008

The first description of the dental formula and the number of teeth of Scyliorhinus stellaris are presented in this paper based on careful examination of teeth from 54 specimens (37 males and 17 females) collected in the eastern central Adriatic.
A pilot experiment of tagging the deep shrimp Aristeus antennatus (Risso, 1816)
Authors: Relini M. , Maiorano P. , D'Onghia G. , Orsi Relini L. , Tursi A. , Panza M.
Published: October 2008

A tagging experiment of the blue and red shrimp, Aristeus antennatus was carried out in the Ionian Sea, off Roccella Jonica (RC). The experiment involved 45 shrimps, caught by trawling at night at about 100-150 m in depth. One month after tagging one specimen was recaptured at about 10 nautical miles from the releasing point. As the first case of tagged recaptured deep sea shrimp, this experiment brings important results about the feasibility of experimental studies on displacement and growth and gives the first direct proof of the migratory abilities A. antennatus.
Considerations on the biology of Plesionika edwardsi (Brandt, 1851) (Decapoda, Caridea, Pandalidae) from experimental trap catches in the Spanish western Mediterranean Sea
Authors: García Rodríguez M. , Esteban A. , Pérez Gil J. L.
Published: October 2008

In this study, the results obtained from three experimental trap shrimp (Plesionika edwardsi) fishing cruises in three different seasons are presented. They were carried out during a total of 50 days, of which 43 days were of effective fishing, covering the whole Spanish Mediterranean coast including the island of Alborán. On the whole, the fishing depth varied between 220 and 384 m, with a mean depth of 318 m. The target species appeared in 81% of the total samples carried out, with a mean yield (cpue) of 108.6 g/trap/day. The largest yields (cpue) of this species were from the Balearic islands, followed by Levant region, whereas the Alborán sea gave the lowest yields. The largest mean length was observed on the Levant zone, but on the contrary the smallest mean lengths were found towards the south, more specifically at Alborán island. Significant differences were found in both the relative and absolute growth, between males and females, with equilibrium in the ratio of the sexes (0.49). A total of 15 crustacean and 12 fish species were identified as accompanying fauna, with Conger conger, Plesionika narval and Scyliorhinus canicula being the most important, based on their mean cpue, although differences in the appearance and yields of the species were found in the different zones and depths. However, the mean yields of these species were very low, due to the high selectivity of the fishing gear used. The appearance of Heterocarpus ensifer, deserves a special mention, since it is the second documented record of the species in the Mediterranean.
The description of Austroglossus pectoralis (Teleostei: Soleidae) larvae from the South-east coast of South Africa
Authors: Wood Aidan D.
Published: October 2008

Preflexion and flexion larval stages of the East coast sole Austroglossus pectoralis are described. Larval morphology was consistent with that of other soleids. The yolk-sac was evident in larvae up to 2.9 mm BL. Flexion is evident in some 3.5 mm BL larvae and in all larvae > 3.8 mm BL. Larvae have 50 to 58 (8-10 + 40-49) myomeres and a large protruding gut. The head profile is rounded initially and becomes convex after flexion. Teeth are present at 4.0 mm BL and are initially robust, becoming elongate and incisor-shaped after flexion. Pectoral fins are present but no rays have developed in the largest specimen. The sequence of fin anlagen development is caudal, dorsal and anal. Eye migration is not evident in the largest (8.8 mm BL) specimen examined. Pigment is evident over the fore- and mid-brain, snout and lower jaw, and along the ventral and dorsal midline of the trunk and tail. The ventral and lateral walls of the gut also bear melanophores. The larvae of A. pectoralis are compared with previously described soleid species which are found in southern African waters, including its congeneric A. microlepis.
Short-term fluctuations in bivalve larvae compared with some environmental factors in a coastal lagoon (South Portugal)
Authors: Chícaro Luis M.Z. , Alexandra Chícharo M.
Published: October 2008

In this study, short-term fluctuations in bivalve larvae were compared with some triggering factors for a period of sixteen months. Data on the abundance of planktonic larvae, collected two to three times a week were related to water temperature, salinity, wind velocity, tidal amplitude and chlorophyll a. Higher densities of planktonic bivalve larvae were caught between May and August, but intense fluctuations in abundance were observed. Planktonic bivalve larvae of eighteen taxa were identified. Larvae of Mytilus galloprovincialis, Cerastoderma edule, Ruditapes decussates and Venerupis spp. were the most abundant. The seasonal fluctuations of bivalve abundance seem to be controlled by temperature, the major factor in the timing of the reproduction of bivalves. Nevertheless, advection may be also a key factor during the planktonic life of bivalve species in coastal systems, such as the Ria Formosa.
Basin-scale changes of total organic carbon profiles in the eastern South Atlantic
Authors: Alvarez-Salgado X. A. , Pérez F. F. , Ríos A. F. , Doval M. D.
Published: October 2008

Total organic carbon (TOC) samples were collected at 6 stations spaced ~800 km apart in the eastern South Atlantic, from the Equator to 45°S along 9°W. Analyses were performed by high temperature catalytic oxidation (HTCO) in the base laboratory. Despite the complex advection and mixing patterns of North Atlantic and Antarctic waters with extremely different degrees of ventilation, TOC levels below 500 m are quasi-constant at 55±3 µmol C l-1, pointing to the refractory nature of deep-water TOC. On the other hand, a TOC excess from 25 to 38 g C m-2 is observed in the upper 100 m of the permanently stratified nutrient-depleted Equatorial, Subequatorial and Subtropical upper ocean, where vertical turbulent diffusion is largely prevented. Conversely, TOC levels in the nutrient-rich upper layer of the Subantarctic Front only exceeds 9 g C m-2 the deep-water baseline. As much as 70% of the TOC variability in the upper 500 m is due to simple mixing of reactive TOC formed in the surface layer and refractory TOC in deep ocean waters, with a minor contribution (13%) to oxygen consumption in the prominent subsurface AOU maximum at 200-400 m depth.
Morphometric diversity of the pulmonate limpet Siphonaria lessoni in different coastal environments
Authors: Tablado Alejandro , López Gappa Juan
Published: October 2008

Siphonaria lessoni (Blainville, 1824) is the most abundant marine gastropod in the rocky intertidal zone of Buenos Aires Province, Argentina. The morphology of this species was studied in 6 sites near the city of Quequén, differing in intertidal height and degree of exposure to wave action and pollution. Shell length, width, height, and the distance from apex to posterior shell margin were measured, as well as the dry weight of both the shell and limpet body. A data matrix of 600 individuals (100 limpets per site) by 6 variables was analyzed by Principal Component Analysis (PCA) and Discriminant Analysis (DA) in order to compare size and shape differences among sites. As expected, axis I of the PCA explained a very high percentage (87.7 %) of total variance, and can be interpreted as a size factor. Axis II, which summarised 6.9 %, may be regarded as expressing shell shape. Limpets not exposed to wave action within Quequén Harbour showed the highest values in all variables, whereas individuals living within the Brachidontes rodriguezi (d´Orbigny, 1846) community were very small and highly variable. Limpets heavily exposed to sewage at mid intertidal levels had a subcentral shell apex and were relatively very low. Classification of individuals by DA showed that the most characteristic morphology corresponded to limpets living at mid intertidal level close to a sewage outfall, or within Quequén Harbour (94 and 97 % correct reallocations, respectively). The influence of different physical and biotic factors on the morphology of Siphonaria lessoni is discussed.
Melanonus zugmayeri Norman, 1930, captured off Portugal. A review of the current knowledge on this species
Authors: Henriques Miguel , Murta Alberto G. , Cabral Henrique N.
Published: October 2008

The capture of two specimens of Melanonus zugmayeri Norman, 1930 (Melanonidae) off Portugal was reported. Morphometric and meristic characteristics of the specimens examined were presented. One of the specimens represented a new size record for the species. The available data on the specimens caught in other geographical areas was comparatively analysed and the current knowledge on the species was discussed. Due to the lack of data to support the existence of more than one species of Melanonus, further taxonomic revisions would need more specimens, especially from the southern oceans.
Population size and exploitation of giant squid (Dosidicus gigas D'Orbigny, 1835) in the Gulf of California, Mexico
Authors: Morales-Bojórquez Enrique , Hernández-Herrera Agustín , Nevárez-Martínez Manuel O. , Cisneros-Mata Miguel Ángel , Guerrero-Escobedo Francisco Javier
Published: October 2008

The most important landing sites of the giant squid (Dosidicus gigas D´Orbigny, 1835) fishery in the Gulf of California, Mexico are Guaymas, in Sonora and Santa Rosalía, in Baja California Sur. An increase in the species biomass resulted in increased landings, ranging from 6, 200 tons in 1994 to 140,000 tons in 1996. The development of a management strategy for this fishery based on the proportional escapement has been suggested. This necessitates the estimation of the population size when the fishing season begins in order to determine the amount of fishing effort. Weekly catch and effort data were reported from October 1995 to March 1996 for three fleets operating in the Gulf of California. The population size estimated using a maximum likelihood model was 82,000 tons with a proportional escapement of 66%.
Species identification of two sympatric hakes by allozymic markers
Authors: Roldán M. I. , Pla C.
Published: October 2008

Samples were collected from hake species Merluccius australis and M. hubbsi in the south west Atlantic Ocean. Enzyme electrophoretic analysis of the eye, liver and muscle revealed 5 out of 33 genetic loci with species-specific allelic frequencies. These five loci provide a set of genetic markers for individual classification.
Fecundity and egg volume in Norway lobster (Nephrops norvegicus) from different depths in the northern Tyrrhenian Sea
Authors: Mori Mario , Modena Milena , Biagi Franco
Published: October 2008

The relationships between fecundity and egg volume of Norway lobster (Nephrops norvegicus) inhabiting three different depth ranges (200-300, 350-450, and 500-550 m) in the North Tyrrhenian Sea (western Mediterranean) were compared. Fecundity was not dependent on depth and egg volume did not vary with female size. The egg volume of females collected in the shallowest areas (200-450 m) was instead significantly larger than that collected in deeper waters (500-550 m). Possible explanations for this fact are examined.
Sexual reproduction of Nausithoe aurea (Scyphozoa, Coronatae). Gametogenesis, egg release, embryonic development, and gastrulation
Authors: Morandini André C. , Da Silveira Fábio L.
Published: October 2008

The structure of the ovaries and testes of Nausithoe aurea, reared in the laboratory, is described to update the knowledge of coronate scyphomedusae gametogenesis and early development. The testis is similar to those of other scyphozoans. The organization of the ovary agrees with the description for other coronates, with free oocytes in the mesoglea. The oocytes develop in a limited region of the gastrodermis, and a maturation gradient is observed from this point on. Egg release, embryonic development, and gastrulation mode of Nausithoe aurea are also described. Egg production was continuous for 55 days, and the output of released eggs oscillated without observed cue. Cleavage was holoblastic and adequal, but after the 8-cell stage, the cleavage became pseudospiral. Gastrulation occurred through multipolar ingression and began 24 hours after fertilization.
Improved methods for generating and estimating turbulence in tanks suitable for fish larvae experiments
Authors: Stiansen Jan Erik , Sundby Svein
Published: October 2008

An experimental design has been developed for the purpose of testing the response of larval fish feeding to turbulence. The main purpose of the design is to reproduce natural turbulence within the range of scales relevant to the feeding processes. The design is based on grid-generated turbulence in a circular tank with a diameter of 1.5 m and a water depth of 0.90 m. The spatial distribution of the turbulence was measured. The data analysis of our experiment indicate that we successfully simulated natural turbulence covering six orders of magnitude for the energy dissipation rate (4*10-11 - 2*10-4 W/kg) and over three orders of spatial scales from the Kolmogorov microscale (0.3 mm -13 mm) to the size of the tank. It is concluded that the tank is well designed for studies of zooplankton - larval fish interactions, as the turbulence is generated on a range of scales similar to the separation distance between the zooplankton particles found in nature. The short and relatively slow movement of the grid in addition to the relatively large volume of water should make it possible for the larvae to avoid extreme shears, and minimises mechanical impact on larvae behaviour compared to other known turbulence generating systems. A method is developed to calculate the turbulent energy dissipation rate in a zero mean velocity field, assuming the turbulent cascade follows a -5/3 law in the inertial subrange. This method is also expanded for use on noisy time series. Comparisons with five other methods have been conducted. The comparisons show that Taylors frozen turbulence hypothesis can be used even when the ratio between the turbulent and the mean velocity is approximately 1.
Preliminary estimate of spawning frequency and batch fecundity of Brazilian flathead, Percophis brasiliensis, in coastal waters off Buenos Aires Province
Authors: Militelli M. I. , Macchi G. J.
Published: October 2008

Spawning frequency and batch fecundity were estimated for Brazilian flathead, Percophis brasiliensis, in Argentine coastal waters. Samples of this species were collected during the spawning period in November 1998 and 1999. Spawning frequency, determined using the percentage of females with postovulatory follicles, was about 17% during November 1998. This percentage indicates that P. brasiliensis spawned, on average, once every 6 days during this month. Batch fecundity, estimated from counts of hydrated oocytes, was fitted to a power function of length and a linear function of ovary-free female weight. Batch fecundity ranged from 37,500 (47 cm total length) to 614,300 (68 cm total length) hydrated oocytes. Relative fecundity estimated for the two years sampled ranged from 95 to 672 hydrated oocytes/g of female weight (ovary-free). Annual differences in the size-batch fecundity relationship and in the relative fecundity were observed.
An indirect approach to estimate spawning fraction as applied to Sardinops sagax from northern Chile
Authors: Claramunt Gabriel , Roa Rubén
Published: October 2008

The spawning fraction of fishes with multiple spawnings and indeterminate fecundity is normally estimated through biologically intensive and time-consuming histological procedures, such as the one based on the proportion of females with post-ovulatory follicles of 1 day of age. Alternative methods based on macroscopic observations of the gonads are desirable. We conceptualize the spawning fraction as an area under a normal distribution of females classified according to oocyte diameters in the more advanced batch. The area depends on the value of two parameters of the normal distribution (mean and standard deviation) and the diameter at which the oocytes start hydration, when they are ready to be spawned. This conceptualisation was applied to Sardinops sagax of northern Chile, for which additional knowledge allowed us to reduce the problem to specifying a single property of the normal distribution: the standard deviation. Calibration of the area under the normal curve against the spawning fraction derived from histological information yielded a calibrated standard deviation parameter in a monthly series spanning one year. This parameter in turn was statistically related to the gonadosomatic index, as a relative measure of gonadic development which is easy to obtain for any given fish population. Furthermore, the gonadosomatic index was shown to be a proper description of size-standardized gonadic development. The equation relating this index and the standard deviation was then used to predict the spawning fraction which was in close proximity to the histologically-derived spawning fraction. Through this approach the gonadosomatic index can be used for years in which no histological information is available, providing an indirect way to obtain the spawning fraction when a time series of the index is available.
Seasonal distribution and spawning of small tunas (Auxis rochei and Sarda sarda) in the Northwestern Mediterranean
Authors: Sabatés A. , Recasens L.
Published: October 2008

Bullet tuna, Auxis rochei and Atlantic bonito, Sarda sarda are the most abundant small tuna species in the Mediterranean Sea. Both species are commercially exploited by a small-scale inshore fishery off the Catalan coast. Catches of A. rochei are highly seasonal, with maximum values in the warmest months (June to September), which is also the spawning period. Larvae of A. rochei were collected between July and September and were particularly abundant in July, when the mean sea surface temperature was 25.4ºC. In summer, adults of this species migrate from the Atlantic to the Western Mediterranean, including the Catalan Sea, to spawn, but they are not found in this last region during the colder months. S. sarda is taken all year round in the Catalan Sea, with maximum catches from September to March, and minimum levels during the spawning period (May to July). Larvae of this species were only observed in July and larval abundance was considerably lower than that of larval A. rochei. Unlike A. rochei, S. sarda is resident over the continental shelf in the Western Mediterranean all year long, but at the beginning of summer, coinciding with the arrival of the other species, it moves to other areas in order to spawn.
Life cycle of the pelagic goby Aphia minuta (Pisces: Gobiidae)
Authors: Iglesias M. , Morales-Nin B.
Published: October 2008

Reproductive aspects of the transparent goby Aphia minuta (n=2977, 14-45 mm total length (TL)) were studied in Majorcan waters, western Mediterranean, during the fishing season (December to April) from 1985 to 1993. Male:female sex ratio was 1:1. Size at first maturity was 38 mm TL for females and 34 mm TL for males. Oocyte size-frequency distribution indicated that A. minuta is a single spawner. Fecundity of A. minuta ranged from 935 to 2648 oocytes. The breeding season extended from December to April with a peak in March. After a single reproduction at 5-6 months of age, most of the specimens disappeared from the fishing areas. Recruitment to the fishing area occurred in late December and early January (14-24 mm TL, age 2-3 months). On the other hand, the hatch date back-calculated from the age in days and the date of capture of individuals of A. minuta during the fishing season, indicated a spawning peak in autumn (September-October), six months after the peak of observed spawning. Schools of A. minuta were detected by acoustic methods, during the fishing season (winter-spring) in fishing areas (5-40 m depth), principally inside bays, and during the rest of the year (summer and autumn) in deeper areas (40-90 m), outside bays, with water temperatures between 13 and 16ºC and a high seasonal productivity in each depth range. Therefore, we propose that A. minuta has two annual cohorts in the western Mediterranean, corresponding to two main spawning in spring and autumn, respectively. Life history pattern indicated that we only know the winter cohort resulting from the autumn spawning. Meanwhile the summer cohort (spring spawning) grows and reproduces in deeper areas not being targeted by the fishery. Indirect validation is provided from information from other areas. The relevance of the life cycle is discussed in relation to fishery management.
Checklist and annotated bibliography of decapod crustacean larvae from the Southwestern European coast (Gibraltar Strait area)
Authors: González Gordillo J. I. , Dos Santos A. , Rodríguez A.
Published: October 2008

Studies on decapod larvae entailing identification of specimens collected from plankton should be based on sound bibliographic sources that contain morphological descriptions of the species cited in the area. In order to facilitate this bibliographic search, we present a survey of the literature in which decapod larvae from the Gibraltar Strait area (encompassing most of the Mediterranean and northeastern Atlantic decapod crustacean species) are partially or completely described. Among these, the most accuratly identified larval specimens are pointed out. For each original case the taxon assigned by the author, types and numbers of stages described and the origin of the studied larvae are noted. Morever, a checklist of 377 species is given for Gibraltar Strait decapod crustaceans. Of all the species recorded in the area, larval descriptions are known, at least partially, for 220 species (58,35 %), but for 36 (9,54 %) morphological descriptions are sufficiently accurate for a correct identification from plankton specimens.
Epidemiology of Pennella sp. (Crustacea: Copepoda), in exploited Illex coindetii stock in the NE Atlantic
Authors: Pascual S. , González A. F. , Gestal C. , Abollo E. , Guerra A.
Published: October 2008

The spatio-temporal distribution of the mesoparasitic copepod Pennella sp. on the short-finned squid Illex coindetii was studied monthly during 1993 in the southeastern North Atlantic (Galician waters, NW Spain). A total of 600 individuals were analysed separately considering two areas (north and west) with different hydrographical characteristics. Six pennellid stages were found: a copepodite, four chalimus stages and the free-living adult male and female. Epidemiology was assessed using the parasite demographic parameters. The results revealed a marked seasonal pattern in the number of parasites in squid samples from the northern area. This seasonal pattern was not detected in squids from the western area. The observed frequency distributions of parasites on the host population were aggregative at each sampling area. Infection values were extraordinarily high when they are compared with published host-parasite records for other representatives of the genus Pennella. Advantages of the parasite aggregation pattern and possible explanations of the seasonality variations in the number of parasites observed in squid samples from the northern area are discussed.
New Antarctic records of Herpyllobius Steenstrup and Lütken, 1861 (parasitic Copepoda) from the EASIZ-III cruise, with description of two new species
Authors: López-González Pablo J. , Bresciani José
Published: October 2008

Two new species of the genus Herpyllobius Steenstrup and Lütken, 1861, H. vanhoeffeni, and H. luetzeni are described associated with polynoid polychaetes collected during the EASIZ III cruise in the Bransfield Strait, Antarctic Peninsula. New records of Herpyllobius antarcticus Vanhöffen, 1913, and H. polarsterni López-González et al., 2000 from Antarctic Peninsula and Eastern Weddell Sea are also given. Including the present records, 17 species of Herpyllobius are now known, 11 of which having been reported from the Southern Hemisphere. The ordinal position of the Herpyllobiidae is discussed according to phylogenetic inferences from the antennular ontogenetic features of the copepodid males of two of the three known genera in the family, Herpyllobius and Eurysilenium Sars, 1870.
Embryonic and larval development of Lipophrys pholis (Pisces: Blenniidae)
Authors: Faria Claudia , Borges Rita , Gil Fátima , Almada Vitor C. , Gonçalves Emanuel J.
Published: October 2008

Information on the early ontogeny of Lipophrys pholis is scattered and incomplete. In this paper we describe for the first time the full developmental sequence from egg to juvenile in controlled conditions. In addition, some notes on the spawning behaviour of adults and the behaviour of larvae are provided. During oviposition, the female follows the male´s path, suggesting that the male may apply sperm on the nest before spawning. Embryonic development lasted 16 days (17ºC) and larval development to settlement lasted 29 days (15.5-17.5ºC). At hatching, mean larval total length was 5.0 mm. The larvae hatched with the mouth and anus opened, with pigmented eyes and almost no yolk, and started to feed within one day. They first settled 29 days after hatching (13-14 mm TL) and showed full juvenile pigmentation and behaviour 8 to 9 days later (17-19 mm TL).
Determination of age and growth of the striped seabream Lithognathus mormyrus (Sparidae), in the Canary archipelago by otolith readings and backcalculation
Authors: Pajuelo José G. , Lorenzo José M. , Méndez María , Coca Josep , Ramos Antonio G.
Published: October 2008

The age and growth of the striped seabream Lithognathus mormyrus caught off the Canary Islands (central-east Atlantic) from January to December 1999 were studied. A total of 496 individuals, ranging in size between 113 and 350 mm total length, were examined. Otoliths clearly showed the ring pattern common to teleost fishes. One year´s growth was made up of one opaque and one translucent ring. The opaque ring was deposited during the summer months and the translucent one during the winter months. Fish aged 0-8 years old were found. The von Bertalanffy growth parameters for all fish were: L?=427 mm, k=0.19 year-1, and t0=1.46 year. The otolith readings for estimating age and growth were confirmed by using the backcalculation method.
A new species of Halcampella (Actiniaria, Halcampoididae) from the eastern Weddell Sea and Antarctic Peninsula
Authors: Rodríguez Estefanía , López-González Pablo J.
Published: October 2008

A new species of soft-bottom-dwelling sea anemone of the genus Halcampella is described and illustrated based on 47 specimens collected during the Polarstern cruises ANT XV/3 and ANT XVII/3 to the Antarctic Peninsula and the eastern Weddell Sea. The new Halcampella species is easily distinguishable from its congeners by the number of cycles of mesenteries and tentacles, the cnidae and the geographic distribution. The new species is described and compared to the available type material of the other species of the genus and new cnidae data are given for H. maxima Hertwig, 1888 and H. robusta Carlgren, 1931. According to other authors H. endromitata (Andres, 1881) is considered a nomen dubium and H. maxima is here proposed as the types species of the genus.