Wyniki wyszukiwania

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Patterns of the parasite communities in a fish assemblage of a river in the Brazilian Amazon region

100%

Baia R. R. J., Florentino A. C., Silva L. M. A., Tavares-Dias M.

Acta Parasitologica

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2018

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tom 63

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nr 2

2

Food and feeding habits of the blackspotted smooth-hound, Mustelus punctulatus (Elasmobranchii: Carcharhiniformes: Triakidae), from the northern Adriatic

100%

Lipej L., Mavric B., Resek S., Cherif M., Capape C.

Acta Ichthyologica et Piscatoria

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2011

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tom 41

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nr 3

Background. The blackspotted smooth-hound, Mustelus punctulatus Risso, 1826, has been regularly caught in the northern Adriatic Sea, although a decreasing trend in its catches was observed off the coast of Slovenia within the last decade. The knowledge of feeding behaviour of elasmobranch fish species, through understanding of the local food web structure, contributes to better and more efficient fish stock assessment and ecosystem modelling. This study is a first step in determining the prey consumption by the blackspotted smooth-hound in the area. Materials and methods. A total of 151 blackspotted smooth-hounds caught by commercial fishermen in the Gulf of Trieste from 4 June 2002 to 4 June 2003 were examined in this study. The stomach contents were removed, sorted and identified to the lowest possible taxon using identification keys. Preys were counted and weighed. Frequency of occurrence (F%), relative abundance (N%), the percentage by weight (W%), the Index of Relative Importance (IRI), and its standardized value (%IRI) were calculated following standard procedures. For comparing the diet between four different size classes we calculate average prey weight, dietary diversity, average meal, and trophic level for each size class. Results. Atotal of 130 fish stomachs contained prey items.Crustaceanswere themost important prey items (IRI%= 56.14), whereas cephalopods were the second mostly preyed animals (IRI% = 20.2). Teleost fish and bivalves were also found in the stomachs. The most important prey species was Solecurtus strigillatus. Larger sharks consumed larger preys. Male and female sharks consumed similar food. Juvenile individuals consumed predominantly crustaceans, while cephalopods were more important in the diet of adult individuals. The calculated trophic index (TROPH) of M. punctulatus from northern Adriatic Sea was 3.7, showing that it is a highly carnivorous species. Conclusion. This study is a first step in determining prey consumption by Mustelus punctulatus which is, despite the fact that is still common in the area, a rather poorly known species. For elucidating the role of benthic sharks in the study area the further step would be to study the diet of a closely related common smooth-hound M. mustelus.

3

Upper Vistula River: response of aquatic communities to pollution and impoundment. VII. Bioassay studies of water trophic state with Chlorella pyrenoidosa growth test

100%

Bednarz T.

Polish Journal of Ecology

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2002

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tom 50

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nr 2

In the Upper Vistula River course three sections were distinguished: first, at 11 km of the river course, with low trophic level of water (mean yearly yield <30% of Chlorella pyrenoidosa Chick. control cultures), second, up to 66.2 km of the river course, with the moderate trophic level (between 30-50% yield of control), third below 115.6 km of the river course, with the high trophic level (between 50-80% of control yield). The highest water trophic level (80% of control cultures yield) was evidenced at 115.6 km of the river course, due to the input of industrial and municipal sewage. The yield of Chlorella cultures was highly significantly positively correlated with the content of organic matter, electrolytic conductivity, P-PO₄, N (as N-NH₄+N-NO₃), S-SO₄, Ca and Mg concentration in the water. In case of Cd, Cu, Pb, Mn, Zn no correlation was found.

4

Phytoplankton communities at different depths in two eutrophic and two oligotrophic temperate lakes at higher latitude during the period of ice cover

100%

Danilov R. A., Ekelund N. G. A.

Acta Protozoologica

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2001

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tom 40

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nr 3

5

Hydroacoustics as a tool for studying the impact of habitat modification [degradation] upon fish: a review

100%

Godlewska M., Zalewski M.

International Journal of Ecohydrology and Hydrobiology

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2001

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tom 01

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nr 3

Hydroacoustical methods due to their very high resolution in time and space can be used to register subtle changes in fish distribution and behaviour, thus enabling observation of the effect of habitat modification upon the fish. A number of examples have been presented which show dependence between fish parameters measured acoustically (such as depth, density, degree of aggregation, length frequency distribution), and different environmental parameters characterising the habitat quality (trophic levels, presence of chemicals, littoral coverage, predation pressure, temperature and oxygen gradients). This suggest that by performing hydroacoustical monitoring one can measure fish reactions to the habitat changes on a scale and with an accuracy not available with other methods.

6

Food and feeding habits of the red mullet, Mullus barbatus (Actinopterygii: Perciformes: Mullidae), off the northern Tunisian coast (central Mediterranean)

80%

Cherif M., Ben Amor M. M., Selmi S., Gharbi H., Missaoui H., Capape C.

Acta Ichthyologica et Piscatoria

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2011

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tom 41

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nr 2

Background. The red mullet, Mullus barbatus L., is abundantly captured and targeted throughout the year in Tunisian waters but not all aspects of its biology have been studied well. One of them—the feeding behaviour of this fish may be important for stock assessment, ecosystem modelling, and understanding mechanism and processes which structure and influence the fish assemblages. The aim of this paper is to describe the diet of specimens from the northern coast of Tunisia, to analyse seasonal variations in its composition and to delineate feeding intensity in relation to sex and size. Materials and methods. Red mullet were sampled from different landing sites along the northern Tunisian coast and the Gulf of Tunis. Random samples were taken from both commercial and demersal trawlers from January to December 2005. A total of 472 specimens were examined following the commonly accepted procedures. The following parameters were analysed: vacuity index, percentage frequency of occurrence, percentage numerical abundance, percentage gravimetric composition, and index of relative importance. The trophic level for any consumer species was calculated, for total sample, but also in related to size, sex, and season. Results. Mullus barbatus mainly fed on crustaceans and polychaetes. According to the classification of fishes in functional groups based on their TROPH red mullet is an omnivorous feeder, animal species being preferential preys. Basing on data assembled by Stergiou and Karpouzi for the Mediterranean ichthyofauna, the estimated trophic levels for the red mullet ranged between 2.79 and 3.57 units. Such within-species differences in trophic levels might reflect the combined effect of the following factors: area, year, length structure, and differential fishing pressure between years and/or areas, because fishing removes the largest individuals of a species, which generally have higher trophic levels. Conclusion. The red mullet is not only omnivorous, but also opportunistic feeder with trophic level related to body size, season, geographic area and fishing pressure.

7

On the use of a simple primary productivity model to assess the skill of a physical ocean model

80%

Kantha L., Carniel S., Clayson C. A., Sclavo M.

Oceanological and Hydrobiological Studies

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2011

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tom 40

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nr 2

8

The use of stable isotope analyses in freshwater ecology: current awareness

80%

Grey J.

Polish Journal of Ecology

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2006

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tom 54

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nr 4

Ecological research using stable isotopes has progressed rapidly during the last 20 years and although more studies are including the addition of isotopically labelled compounds at tracer levels, the overwhelming majority rely on measurements of natural abundance ratios. Access to isotope ratio mass spectrometry has increased, spurred on by awareness of the techniques and increasing demand, and consequently cost of sample analysis has dropped. Today stable isotopes of carbon (¹³C/¹²C), nitrogen (¹⁵N/¹⁴N), sulphur (³⁴S/³²S), oxygen (¹⁸O/¹⁶O), and hydrogen (²H/¹H) can be determined routinely. Perhaps one of the most appealing attributes of isotopic signatures is their potential use to find patterns and determine mechanisms across a range of scales from the molecular level through to characterising whole food webs, reconstructing palaeoenvironments, tracing nutrient fluxes between ecosystems and identifying subsidies, or migrations of organisms. Ecologists from every discipline who are unlikely to have been trained as isotope chemists have added stable isotope analysis (SIA) to their “toolbox”, but often increasing use leads to increasing abuse. The usefulness of SIA arises from predictable physical and enzymatic-based discrimination between biological and non-biological materials leading to different isotopic compositions. Without some ecological understanding of these, interpretation of isotope-derived data can often be flawed. Here, I explore how SIA recently has been used for research in aquatic ecology, reviewing how some of these techniques have allowed elucidation of key processes in aquatic systems such as the contribution of allochthony to lake food webs, and discuss the “state of the art”. Included are some thoughts on where our knowledge in aquatic ecology remains deficient and how continued development and future application of SIA and interdisciplinary methodologies may be applied.

9

The basic paths of energy flow and matter transformations in a lowland dam reservoir ecosystem

80%

Zurek R.

Oceanological and Hydrobiological Studies

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2007

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tom 36

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nr Suppl.2

10

Zinc and copper concentrations in litter invertebrates of different trophic levels and taxonomic positions

80%

Maryanski M., Niklinska M., Kramarz P., Laskowski R., Nuorteva P.

Archiwum Ochrony Środowiska

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1995

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nr 3-4

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Bacteria and parasites on the gills of pike Esox lucius L. and tench Tinca tinca [L.] as indices of the trophic level of Oswin Lake [Northeastern Poland]

80%

Wlasow T., Zmyslowska I., Lewandowska D., Mierzejewska K., Idzikowski R., Ziomek E.

Archives of Polish Fisheries

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2003

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tom 11

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nr 2

The presence of bacteria and parasites on the gills of pike and tench from Oświn Lake in the Seven Islands Reserve was investigated. Parallel bacteriological analyses of the water were done. The materials were sampled in May-June, July, October 1999, six years after the water level had been increased. The bacteriological and parasitological results both indicate that this body of water is eutrophic. The increase in the incidence of infection with Ergasilus sieboldi and an increase in the number of heterotrophic bacteria were observed simultaneously on the gills. Based on the parasitological and microbiological analysis of gills, the prognosis for the health of pike is unfavorable.

Ograniczanie wyników

Patterns of the parasite communities in a fish assemblage of a river in the Brazilian Amazon region

Food and feeding habits of the blackspotted smooth-hound, Mustelus punctulatus (Elasmobranchii: Carcharhiniformes: Triakidae), from the northern Adriatic

Upper Vistula River: response of aquatic communities to pollution and impoundment. VII. Bioassay studies of water trophic state with Chlorella pyrenoidosa growth test

Phytoplankton communities at different depths in two eutrophic and two oligotrophic temperate lakes at higher latitude during the period of ice cover

Hydroacoustics as a tool for studying the impact of habitat modification [degradation] upon fish: a review

Food and feeding habits of the red mullet, Mullus barbatus (Actinopterygii: Perciformes: Mullidae), off the northern Tunisian coast (central Mediterranean)

On the use of a simple primary productivity model to assess the skill of a physical ocean model

The use of stable isotope analyses in freshwater ecology: current awareness

The basic paths of energy flow and matter transformations in a lowland dam reservoir ecosystem

Zinc and copper concentrations in litter invertebrates of different trophic levels and taxonomic positions

Bacteria and parasites on the gills of pike Esox lucius L. and tench Tinca tinca [L.] as indices of the trophic level of Oswin Lake [Northeastern Poland]