Search results for " Fish"

Impact of very low crop residues cover on wind erosion in the Sahel

2011

International audience; In the Sahel, with average annual precipitation in the order of 500 mm yr− 1, wind erosion occurs mainly on cultivated millet fields whose surfaces are only partially covered by crop residues. The impact of these residues on wind erosion was not clearly established. The objective of this study is thus to quantify the actual amount of crop residues in traditional Sahelian fields and to determine their impacts on wind erosion by reference to a bare surface throughout the seasonal cycle over several years. At the beginning of the year during dry season, Sahelian farmers use to "clean" their fields, i.e. cut and lay flat on the soil surface any millet stalks still standi…

Heavy metals analysis by non invasive techniques for fish food quality control

2014

Mercury in fish products: what’s the best for consumers between bluefin tuna and yellowfin tuna?

2017

A total of 205 bluefin and yellowfin tuna samples were examined for mercury detection in order to verify possible differences and have a detailed risk assessment of the two tuna species. The results showed significant higher mercury concentration in muscle tissue of bluefin tuna respect yellowfin tuna (p < 0.001) with mean concentration of 0.84 mg/kg and maximum value of 1.94 mg/kg. These differences can be due the different biological and ecological aspects of the two tuna species and to different oceanographic aspects between Atlantic Ocean and Mediterranean sea. The results obtained in this study suggest an advisable containment of the sources of pollution and further studies on the c…

Effects of Plastic Mulching and Basal Nitrogen Application Depth on Nitrogen Use Efficiency and Yield in Maize

2018

The demand for increased grain production to support population and consumption growth has led to increased interest in field management approaches that incorporate plastic mulching and fertilization management. The purpose of this study was to investigate the effects of plastic mulching and basal nitrogen (N)-fertilizer application depth on N balance estimations, N use efficiency (NUE) and maize yield. The experiment was conducted in 2014 and 2015 with six treatments: no N fertilizer and no mulching (CK), traditional broadcast N fertilizer with mulching (T0), basal N-fertilizer application at a depth of 6 cm with no mulching (T1), basal N-fertilizer application at a depth of 6 cm with plas…

Source shape and data analysis procedure effects on hydraulic conductivity of a sandy-loam soil determined by ponding infiltration runs

2017

Performing ponding infiltration runs with non-circular sources could represent a good means to sample completely an area of interest. Regardless of the shape of the source, predicting the expected reliability of the collected data by infiltrometers should facilitate soil hydraulic characterisation and also allow a more conscious use of the field data. The influence of the shape of the infiltration source (i.e., circular or square) and the analysis procedure of the steady-state infiltration data on the saturated hydraulic conductivity, Ks, of a sandy-loam soil was tested in this investigation. Circular and square surfaces sampled with the pressure infiltrometer (PI) yielded similar estimates…

Offsetting land degradation through nitrogen and water management during maize cultivation under arid conditions

2018

Standardization of sperm motility analysis by using CASA-Mot for Atlantic salmon (Salmo salar), European eel (Anguilla anguilla) and Siberian sturgeo…

2019

[EN] It is essential to define an optimized standard method to assess the fish sperm quality to minimize the differences between the results obtained by different laboratories. Only this optimization and standardization can make them useful from academia to industry. This study presents the validation of sperm motility assessment using a CASA-Mot system for three endangered diadromous fish species: European eel (Anguilla anguilla), Atlantic salmon (Salmo salar) and Siberian sturgeon (Acipenser baerii). To attain this goal, different technical and data processing methods were tested: 1) magnification lens (×10 and ×20), 2) Spermtrack® reusable chambers (10 and 20¿¿m depth) and 3) different f…

Mining extraction in the ocean depths: a baseline to understand and reduce acoustic impact on biodiversity.

2020

[ES] A lo largo de la historia, el hombre ha explotado los recursos minerales de la tierra para su supervivencia y desarrollo tecnológico sin un equilibrio con su regeneración. Dado el crecimiento de la población mundial y la reducción de recursos, el hombre comenzó a buscar nuevos depósitos que se encontraron en la década de 1960 en las profundidades de los océanos. Con estos, la humanidad empezò a pensar en extraer los minerales de estos depósitos y esto llevò al nacimiento de Deep Sea Mining (DSM). Las consecuencias de las actividades mineras en las profundidades del mar no se conocen realmente y los efectos pueden ser diferentes: contaminación acústica, contaminación lumínica, contamina…

Baltijas reņģes nārsta vietu un embrionālās attīstības raksturojums Rīgas jūras līcī

1994

Advisor: L. Duškina

Increased susceptibility to predation and altered anti-predator behaviour in an acanthocephalan-infected amphipod.

2007

7 pages; International audience; According to the 'parasitic manipulation hypothesis', phenotypic changes induced by parasites in their intermediate hosts are effective means of increasing trophic transmission to final hosts. One obvious prediction, although seldom tested, is that increased vulnerability of infected prey to an appropriate predator should be achieved by the parasite altering the anti-predator behaviour of its intermediate host. In this study, we tested this prediction using the fish acanthocephalan Pomphorhynchus tereticollis and the freshwater amphipod Gammarus pulex. Firstly, we estimated the relative vulnerability of infected and uninfected gammarids to predation by the b…