bluuebunny/crossref_metadata_2025_split huggingface dataset:
Succession of Chironomus Meigen Species (Diptera, Chironomidae) in Newly Filled Ponds
Authors: Matêna Josef 
Published: February 2007

AbstractThe colonization by Chironomus spp. of two ponds filled after a dry period was investigated. Field data were collected by means of quantitative benthic samples and emergence traps. C. melanescens. C. annularius, C. riparius, C. piger, C. luridus, C. obtusidens, C. plumosus, C. dorsalis and Camptochironomus tentans were determined cytotaxonomically in ponds investigated. C. melanescens and C. annularius appear to be the most characteristic species colonizing in high numbers in newly filled ponds. Larvae of C. annularius grew more slowly in ponds compared with the former one which resulted in a characteristic succession of both larval types. Most species mentioned disappeared completely from the ponds investigated after the metamorphosis of a single cohort. They were replaced by C. plumosus which was often attended by C. annularius in smaller ponds.
The Entomostracan and Rotifer Communities Associated with Submerged Plants in the Norfolk Broadland — Effects of Plant Biomass and Species Composition
Authors: Irvine Kenneth , Balls Hilary , Moss Brian 
Published: February 2007

AbstractThe microcrustacean and rotifer communities associated with submerged aquatic plants were studied over a three‐year period in a series of experimental ponds, created within a fenland drainage ditch. Seasonal abundance and spatial distributions were assessed. The ponds contained a varying amount of vegetation, dominated either by Ceratophyllum demersum or Stratiotes aloides and this had consequences for the ponds' animal communities. Increasing densities of Ceratophyllum were associated with increases in weed‐associated entomostracans whereas increases in Stratiotes led to a general decrease in associated animals. Increases in both plant species led to reductions in abundance of Daphnia, but to differing amounts. A relatively low density plant population in the presence of zooplanktovorous fish did not provide a refuge from predation for large‐bodied Cladocera.
Long‐term Dynamics of Benthic Invertebrate Standing crop Palos Verdes Shelf, Southern California
Authors: Maurer Don , Haydock Irwin 
Published: February 2007

AbstractWet weight standing crop of macrobenthic invertebrates from the Palos Verdes Shelf, California showed several major fluctuations from 1972 to 1986, mainly due to the bivalve Parvilucina tenuisculpta and the echiuroid Listriolobus pelodes. From 1972 to 1986 mean biomass was 285 g/m2. When this value was compared with standing crop from other shelves, Palos Verdesstanding crop fell within the range documented for the tropics to higher latitudes. There was a small decline with increased effects of El Nino in 1983. When Palos Verdes standing crop was compared to the biomass portion of the Pearson‐Rosenberg SAB curve, it was concluded that their model is probably not applicable on this portion of the shelf. Finally, the long‐term data base provided the opportunity to propose several hypotheses. These concerned the potential effect of L. pelodes on species diversity and hydrogen sulfide in the sediment and the influence of L. pelodes on excess standing crop.
Die Feinstruktur der Kolbenzellen (Schreckstoffzellen) in der Epidermis von Astyanax mexicanus Filippi 1853 (Characinidae, Pisces) und seinen Höhlenderivaten “Anoptichthys”
Authors: Peters Nicolaus , Schmidt Wiebke , Fricke Diethard 
Published: February 2007

AbstractFine Structure of the Club Cells (Alarm Substance Cells) in the Epidermis of Astyanax mexicanus Filippi 1853 (Characinidae, Pisces) and its Cave Forms “Anoptichthys”The club cells in the epidermis of Astyanax mexicanus are of the same ultrastructure as those in other Ostariophysan fish. There are also no essential differences to be found between the club cells of epigean Astyanax mexicanus and its cave forms “Anoptichthys”. Our findings correspond to former statements in that the function of the club cells producing and releasing alarm substances has been maintained in the cave forms.
Phosphorus Losses from the Epilimnion in Římov Reservoir
Authors: Porcalová Petra 
Published: February 2007

AbstractThe amount of settling phosphorus was measured in Římov Reservoir using sediment trap technique from April 1986 to April 1987. Sediment traps were placed at three depths near the dam of the reservoir and at the bottom along the reservoir.The highest amount of phosphorus in trapped material was found during the fall turnover in the epilimnion and near the bottom in both spring periods (1986,1997). During the growing season the changes in dry weight and total phosphorus in settling seston were related to changes of phytoplankton biomass in the trophogenic layer. The amount of trapped phosphorus was higher near the bottom than in the upper layers of the reservoir throughout the year.
Assessment of Water Pollution using Diatom Community Structure and Species Distribution — A Case Study in a Tropical River Basin
Authors: Khan I. S. A. Nather 
Published: February 2007

AbstractA study on biological assessment of water pollution using diatom community structure and species distribution was carried out in the Linggi River Basin, Malaysia which was polluted by various urban, industrial and agricultural wastes. A total of 86 diatom taxa belonging to 21 genera were recorded from all eight sampling stations located in the basin, of which 70 species were found on artificial substrates; the remaining 16 species were recorded exclusively on natural substrates. The number of diatom species observed between the stations varied from 22‐47 species. The dominant diatom species in decreasing order of abundance were Eunotia vanheurckii, Nitzschia palea, Achnanthes saxonica, Gomphonema parvulum and Achnanthes minutissima. The most common clean water species were Achnanthes minutissima, A. linearis and Synedra rumpens. The most tolerant species were Nitzschia palea followed by Gomphonema parvulum and Pinnularia braunii. Eunotia vanheurckii and Navicula cryptocephala occurred in high densities at both unpolluted and polluted stations and can be considered as the common facultative or indifferent species. Although a large number of species were recorded at the unpolluted stations, equivalent number of species were also found at the moderately polluted stations. However, the number of species was reduced at grossly polluted stations. Nevertheless, a marked variation in species association exists between the unpolluted and polluted stations, but not among the polluted stations to distinguish the type and degree of pollution.
The Mechanism Controlling Plant Nutrient Concentrations in the Northern Adriatic Sea
Authors: Gilmartin Malvern , Degobbis Danilo , Revelante Noelia , Smodlaka Nenad 
Published: February 2007

AbstractA 20 year data set for the northern Adriatic was analyzed and the factors establishing the nutrient environment identified. Concentrations ranged widely (TIN 0.0–78, PO2 0.01–1.1, and SiO4 0.0–59 mmol m−3). In early winter remineralization increased concentrations. Characteristic winter, late spring and fall phytoplankton blooms alternately decreased and increased concentrations, as modified by river input. In summer nutrients were minimal under a semi‐closed circulation pattern and high vertical stability, due to closely coupled nitrogen and phosphorus assimilation‐regeneration processes and biogenic silica sedimentation. “New” primary production supported mainly by river input of “new” nutrients approximated “regenerated” primary production supported by regenerated nutrients, making the ecosystem especially sensitive to eutrophication pressure from anthropogenic increases in the Po River nutrient load.
Factors Responsible for Retarding the Eutrophication Rate of Some Mesotrophic Lowland Lakes in N.E. Poland
Authors: Hillbricht‐Ilkowska Anna 
Published: February 2007

AbstractThe chemical composition of watershed waters supplying 13 mesotrophic lakes (in N.E. Poland) including as the deepest lake L. Hańcza, z = 108.5 m (summer total phosphorus [TP] content ≤0.050 mg · 1−1, chlorophyll a ≤5μg · 1−1, SD≥2.5 m) in a typical postglacial lake district (Suwalski Landscape Park) as well as surface and bottom waters of the lakes were studied in summer. Although the underestimated (i.e. including only surface runoff, river inflows and precipitation) yearly TP loading is equal to or higher than the permissible value, the lakes have maintained their mesotrophic features for 20 to 30 years. P sorption to the allochthonous inorganic material as well as decalcification processes in the lakes are probably responsible for this situation, as there is a strong difference between the chemical content of supplying waters and lake waters and as there is a considerable enrichment of P on sestonic particles. As a consequence of the low bio‐availability of P, the midsummer amount of chlorophyll a is lower than predicted from the “TP—chlorophyll‐a” relation found for harmoniously eutrophicating (i.e. P‐limited) lakes.
Zooplankton Dynamics of Lake Escondido (Rio Negro, Argentina), with Special Reference to a Population of Boeckella gracilipes (Copepoda, Calanoida)
Authors: Balseiro Esteban G. , Modenutti Beatriz E. 
Published: February 2007

AbstractThe zooplancton dynamics and the populations of Boeckella gracilipes Daday of Lake Escondido (Rio Negro, Argentina) were studied from March 1987 to March 1988. Rotifers and Cladocerans showed high densities during spring and summer, while copepods were densest in autumn. The vertical distribution study showed that rotifers prefer upper levels of the water column, while cladocerans and copepods prefer lower levels, especially during thermal stratification.Boeckella gracilipes had a sex ratio biassed toward female, though changes in the sex ratio were observed. The clutch size was high in winter when the proportion of ovigerous females was low. The instantaneous birth rates were low during winter and high in summer. This result is related to the thermal cycle of the lake, by the influence of temperature on egg development time. The mortality rates showed a similar pattern, and maximum values were registered in spring and summer.
Diel emergence patterns of chironomids
Authors: Learner Michael , Pickering James , Wiles Roy 
Published: February 2007

AbstractThe diel emergence patterns of 16 chironomid species from a Berkshire lake are characterized. A study of these patterns and those described previously in the literature indicate that the diel pattern for any chironomid species can often be predicted on the basis of the Tribe to which it belongs. Chironomini spp. usually emerge at dusk or at night. Macropelopiini spp. and Metrioenemini spp. characteristically emerge during daylight but the former peak in the morning and the latter peak in the afternoon. Orthocladiini and Tanytarsini spp. exhibit more varied patterns although bimodalism is a frequent feature. The phylogenetic conservatism in the diel patterns displayed implies that these patterns became established early during chironomid evolution, and are, therefore, plesiomorphic.
Note on the survival of algal resting cells during long‐term maintenance in darkness and minimum lake bottom temperature. Comparison of Anabaena (cyanobacteria) and Haematococcus (volvocales)
Authors: Braune Wolfram 
Published: February 2007

AbstractResting cell formation in algae and cyanobacteria is one of the strategies developed for withstanding adverse environmental conditions. This note informs about the different capacities of such resting cells to germinate after long‐term dark preservation at 4 °C in Anabaena variabilis (Cyanobacteria, Cyanophyta) and Haematococcus lacustris (Chlorophyta, Volvocales).
European Catches of Elver of 1928‐1988
Authors: Moriarty Christopher 
Published: February 2007

AbstractData on quantities of glasseels and elvers caught at 11 stations on the western and northern coast of Europe together with abundance indices for glass eels at Den Oever, Netherlands and for larvae in the Bay of Biscay are presented covering the period 1924 to 1988. Large catches were made in the 1960's and 1970's followed by a sudden and widespread, but not universal, decline in the 1980's. Catches within years between stations showed significant correlations in some cases but not in all.
Distribution and Abundance of Glass‐Eels Anguilla spp. in East Australian Waters
Authors: Beumer John , Sloane Robert 
Published: February 2007

AbstractThe invasion of glass‐eels Anguilla species into coastal waters of Eastern Australia is described from the results of sampling as well as a review of pertinent literature. A. reinhardtii has a year‐round invasion in tropical and sub‐tropical waters while A. australis has a similar invasion pattern in temperate waters. The former species is most abundant in latitudes 20‐34° S with the latter species most abundant in latitudes 35‐44° S. A. australis glass‐eels were longer and heavier than those of A. reinhardtii. The recorded distribution and abundance patterns are discussed in terms of rainfall regimes and the movements of inshore currents.
Shape Analysis of Otoliths—a Tool for Indirect Ageing of Eel, Anguilla anguilla (L.)?
Authors: Doering Peer , Ludwig Jürgen 
Published: February 2007

AbstractEel otolith shapes can be separated into distinct groups which can be assigned to certain age groups. The shape is described exactly through Fourier series using the maximum‐projection‐area. Clusters formed by the magnitudes of Fourier descriptors agreed with age groups of three year intervals by 66% (kappa = · 522, p<.001). Artificial shapes for the resulting clusters were constructed from the mean Fourier descriptors. Further studies with eels of known age are needed to validate shape analysis of otoliths as an objective measure for indirect ageing.
Age Determination of Eels in the French Mediterranean Lagoons Using Classical Methods and an Image Analysis System
Authors: Panfili J. , Ximenes M.‐C. , Do Chi T. 
Published: February 2007

AbstractSeveral methods are used for age determination of eels in the French mediterranean lagoons (observation of the whole otolith after clearing, grinding and polishing, dyeing, SEM and image analysis). Two types of otoliths are observed depending on the width of the growth rings which is probably related to the environmental conditions. Furthermore, the growth checks are located nearby or inside the opaque rings. A computer assisted method is developed, with reference to the other methods, with the aim of improving the efficiency of collecting and processing age and growth data. With further developments and increasing knowledge of the life‐history of elvers and juvenile eels, it seems possible to use an image analysis system for ageing eels in lagoons. Nevertheless, the most important point is to validate the results before using them for growth populations studies.
Gonad Sex Differentiation of Anguilla anguilla by Sex Steroids
Authors: Colombo Giuseppe , Grandi Gilberto 
Published: February 2007

AbstractAnguilla anguilla elvers, reared in warm fresh water, were treated with 17 a‐methyltestosterone (MT) and with 17 α‐ethynilestradiol (EE), administered with a commercial diet. A very low proportion of untreated elvers developed as females. A very high proportion of the EE treated elvers developed as females and the gonads differentiated as ovaries at an earlier growth stage. Among the MT treated elvers, in a very low proportion of eels the gonads developed as ovaries, most into a undifferentiated testis‐like gonad and some with abnormal histological features.
Eel Biomass in a Small Lowland Stream
Authors: Moriarty Christopher , Nixon Eugene 
Published: February 2007

AbstractA total of 399 eels were recovered from a rotenone operation in part of a tributary stream of the River Nore. Figures for biomass of 52 kg per ha or 42 kg per km were calculated. Small eels were scarce and the youngest aged was 6 years. The oldest was 28 years and measured 57 cm. The majority of eels in the stream measured between 30 cm and 50 cm and were aged between 10 and 20 years.
Caractéristiques d'une pêcherie d'anguille (Anguilla anguilla) au verveux dans un petit estuaire (Blavet, France). Characteristics of an Eel (Anguilla anguilla) Fyke‐net Fishery within a Small Estuary (River Blavet, France)
Authors: Fontenelle G. , Gascuel D. , Mounaix B. 
Published: February 2007

AbstractFrom 1983 to 1986, an eel fyke‐net fishery was studied within the estuary of Blavet River (Brittany) which was not fished yet. The monthly mean CPUE issued from logbook data can reach 4.8 kg/gear · 24 hours. They largely depend on the locations (the higher the more downstream they are) and on the season as well. The results suggest a rather narrow home range within all the year long. By analyzing the CPUE‐Effort relationship, no overfishing can be noticed, up to now.
Short Note on the Silver Eel Catch on the Lower River Shannon
Authors: Moriarty Christopher 
Published: February 2007

AbstractCatches of eel from the Shannon lake system of 35,000 ha have fluctuated from 10 to 46 t per annum over the period 1964 to 1988. Peak catches are observed at intervals from 3 to 5 years. Catches increased following improvement of fishing gear but otherwise remained steady in spite of a sustained increase in stocks. Migration was observed every month except June. The numbers of female eels>60cm decreased over the period. Male eels ranged from 39 to 44 cm, ages 5 to 15; females from 45 to 99 cm, ages 8 to 30 years.
A Survey of Heavy Metal Levels in Eels (Anguilla anguilla) from some Rivers in East Anglia, England: the Use of Eels as Pollution Indicators
Authors: Barak N. A.‐E. , Mason C. F. 
Published: February 2007

AbstractA survey was made of mercury, cadmium and lead in the liver and flesh of 517 eels from eleven rivers in East Anglia. Eels from some sites showed high metal levels, indicating sources of metal contamination. Eel liver is a suitable indicator of inorganic pollution and the flesh is a suitable indicator of organic pollution.
La pêcherie de civelle (Anguilla anguilla) en Loire (France) en 1987: Evaluation des prises accessoires et impact halieutique. The Glass Eel (Anguilla anguilla) Fishery in the Loire Estuary (France) 1987: Estimate of By Catch and its Effects on Resources
Authors: Guerault D. , Desaunay Y. 
Published: February 2007

AbstractBy‐catch is estimated by sampling the whole fishery (February to April 1987) on the basis of a survey of the fishing effort: 16 species of commercial interest are considered, among them 3 species are dominant: Flounder, sprat and brown shrimp (98,4% of the 49,3 million individuals). By‐catch consists mainly of very young animals (larval or 0‐group stages). An attempt is made to consider the ratio between by‐catch and the potential natural mortality of juveniles.
Studies of Gonadal Steroids Involved in Final Gonadial Maturation in the Japanese Eel, Anguilla japonica, a Review
Authors: Yamauchi Kohei 
Published: February 2007

AbstractVitellogenesis in females and spermatogenesis in males were stimulated by exogeneous gonadotropic preparations. However, the subsequent oocyte maturation and spermiation did not advance because of the insuffiency of circulating 17α, 20β‐dihydroxy‐4‐pregnen‐3‐one (17α, 20β‐diOHprog). At the time of maturation, the injection of 17α, 20β‐diOHprog induced oocyte maturation and ovulation in females and spermiation (increase in volume of seminal plasma and acquisition of sperm motility) in male. These results suggest strongly that 17α, 20β‐diOHprog play a key role in the final maturation of the Japanese eel.
The Use of Mycelia of Penicilium sp. as an Ingredient for Glass Eel Nutrition
Authors: Gonçalvks J. F. , Gomes E. , Amaral L. , Coimbra J. 
Published: February 2007

AbstractThree isoproteic and isoenergetic diets containing fish meal as a protein source (control diet) or incorporating 10 and 20% of protein from mycelia Penicilium sp. as a fish meal substitute were tested during three months for eel fingerlings growth.Some preliminary “in vitro” experiments on the L‐Lysin intestinal absorption in the presence and in the absence of Penicilin (500 mg/l) after 17 h of contact show a positive effect of this antibiotic. No residues of Penicilin were detected in carcass of eels fed 7 days with 100 mg/kg Penicilin in the food.The present results show that the use of Penicilin mycelia in eels diets will have the advantage of increasing growth without any appreciable change in the quality of the carcass and also, eventually, reductions of nitrogen excretion with a positive effect in effluent quality.
Are the same Compounds in Microcystis responsible for Toxicity to Daphnia and Inhibition of its Filtering Rate?
Authors: Jungmann Dirk , Henning Manfred , Jüttner Friedrich 
Published: February 2007

AbstractThree strains of Microcystis when supplied to Daphnia in mixtures with Scenedesmus differed in their power to inhibit filtering rates. The axenic strain PCC 7806 had the strongest effect (93% inhibition with 50% Microcystis in the food). This strain was toxic to daphnids since Daphnia died faster under these conditions than without any food. Strain PCC 7806 also exhibited strong toxicity against mice (LD50 22 mg/kg). When the toxicity against Daphnia and mice was tested with cells of Microcystis PCC 7806 which has been subjected to various extraction procedures, the extraction of freeze‐thawed cells with water slightly reduced the mouse toxicity, eliminated Daphnia toxicity and reduced the inhibition of the filtering rate. After treatment with a lipophilic solvent, the cells of PCC 7806 still showed low mouse toxicity, but no longer inhibition of the filtering rate and no toxicity to Daphnia. Thus, our data suggest that Daphnia toxicity and inhibition of the filtering rate are caused by different compounds, but we cannot rule out the possibility that the factors toxic to mice and inhibitory to the filtering rate are identical.
On the Occurrence of Aphanizomenon flos‐aquae var. Flos‐aquae in Fish Ponds
Authors: Pechar Libor , Fott Jan 
Published: February 2007

AbstractSummer blooms of Aphanizomenon flos‐aquae var. flos‐aquae accompanied by dense populations of Daphnia were common in fish ponds of the district Blatná in 1950s‐1960s. Changes in management (increased stocking densities, decreased usage of superphosphate as fertilizer) made this type of plankton less frequent. The present study documents this trend and suggests explanations.
Seasonality in Nutrients and Phytoplankton Production in Two Shallow Lakes: Waigani Lake, Papua New Guinea, and Barton Broad, Norfolk, England
Authors: Osborne P. L. 
Published: February 2007

AbstractWaigani Lake, near Port Moresby, Papua New Guinea and Barton Broad, Norfolk, England are both shallow lakes nutrient‐enriched from sewage effluent disposal. In Waigani Lake phytoplankton biomass varied seasonally with lower levels (100‐200 mg chlorophyll α m−3) during the wet season increasing to over 400 mg chlorophyll α m−3 at the end of the dry season. Secchi disc depths varied between 0. 11 and 0. 34 m. Phytoplankton productivity in Waigani Lake was very high throughout the year (range: Amax 4,370‐21,000 mg O2 m−3 h−1) but production was lower during the wet season (range: Amax 4,370‐12,700 mg O2 m−3 h−1). High surface productivity was recorded from August to December except on sampling days when the weather was overcast. Productivity throughout the year declined rapidly with depth. Algal biomass in Barton Broad varied from 3‐10 mg chlorophyll α m−3 in winter but increased in spring and was very high in summer (200‐500 mg chlorophyll α m−3). Secchi disc depth varied from 0.21 m in August 1976 to 1.76 m in December. Phytoplankton production in Barton Broad was low in winter (range: Amax 247‐1,250 mg O2 m−3 h−1) but increased markedly in spring and summer with the highest rate (Amax 6,850 mg O2 m−3 h−1) being recorded in August. Surface inhibition was observed during summer except when the weather was overcast. Seasonality in nutrients and phytoplankton in Waigani Lake appear to be related to rainfall. Nutrient concentrations in Barton Broad are more closely related to phytoplankton activity which, in turn, correlates with seasonality in solar radiation.