Driftnet fishing and biodiversity conservation: the case study of the large-scale Moroccan driftnet fleet operating in the Alboran Sea (SW Mediterranean)

Illegal, large-scale driftnets are still used in several Mediterranean areas. According to international official sources, Morocco harbors the bulk of this fleet in the Mediterranean. To ascertain its biodiversity impact, 369 fishing operations (worth 4140 km of driftnets set) made by the driftnet fleet targeting swordfish (Xiphias gladius) based in Al Hoceima (Alboran Sea) were monitored between December 2002 and September 2003. Parallel surveys were made in the main Mediterranean ports and in that of Tangiers, in the Gibraltar Straits, to estimate the total fishing effort. Results showed an active driftnet fleet conservatively estimated at 177 units. Estimated average net length ranges from 6.5 to 7.1 km, depending on the port, though actual figures are suspected to be much higher (12-14 km). Most boats perform driftnet fishing all year round, resulting in very high annual effort levels. A total of 237 dolphins (short-beaked common dolphin, Delphinus delphis, and striped dolphin, Stenella coeruleoalba), 498 blue sharks (Prionace glauca), 542 shortfin makos (Isurus oxyrinchus) and 464 thresher sharks (Alopias vulpinus) were killed by the boats monitored during the sampling period, during the peak of the swordfish fishery, along with 2990 swordfish. Loggerhead turtle (Caretta caretta) was also caught (46 individuals). Estimates for a 12-month period by the whole driftnet fleet yielded 3110-4184 dolphins (both species) and 20,262-25,610 pelagic sharks distributed in roughly equal proportions for P. glauca, I. oxyrinchus and A. vulpinus, in the Alboran Sea alone; further 11,589-15,127 dolphins and 62,393-92,601 sharks would be killed annually around the Straits of Gibraltar. Dolphins suffer from annual take rates exceeding 10% of their population sizes in the Alboran Sea; this unsustainable impact is particularly worrying for D. delphis, because its last remnant healthy population in the Mediterranean occurs in this area. Average catch rate for swordfish, the main target species, amounted to only 0.8 individuals/km net set. Pelagic sharks are actively targeted by a part of the fleet.     

Near infrared spectroscopy techniques for soil contamination assessment in the Nile Delta

Heavy metals concentration is considered one of the factors directly affecting soil and crop quality and, thus, human health. The objective of the current work was to critically examine the suitability of Vis- NIR (350–2500 nm) measurements for calibration procedures and methods to predict contaminated soil. 25 different sites were selected adjacent to drain Bahr El-Baqar east of Nile Delta. Spectroradiometer ASD was used to measure the spectral reflectance profile of each soil site. The concentrations of three heavy metals (Cr, Mn and Cu) were determined in the studied samples. Stepwise multiple linear regression (SMLR) was used to construct calibration models subjected to the independent validation. The obtained regression models were of good quality (R² = 0.82, 0.75, and 0.65 for Cr, Mn, and Cu, respectively). Thus, Visible and Nearinfrared (Vis-NIR) reflection spectroscopy is cost- and time-effective procedure that can be used as an alternative to the traditional methods of determination of heavy metals in soils.     

Phytoalexins from the Vitaceae: biosynthesis, phytoalexin gene expression in transgenic plants, antifungal activity, and metabolism

Resistance of plants to infection by phytopathogenic microorganisms is the result of multiple defense reactions comprising both constitutive and inducible barriers. In grapevine, the most frequently observed and best characterized defense mechanisms are the accumulation of phytoalexins and the synthesis of PR-proteins. Particular attention has been given here to stilbene phytoalexins produced by Vitaceae, specifically, their pathway of biosynthesis (including stilbene phytoalexin gene transfer experiments to other plants) and their biological activity together with fungal metabolism.     

Nitrogen use Rationalization and Boosting Wheat Productivity by Applying Packages ‎of Humic,Amino Acids,and Microorganisms

ABSTRACT

Integrated management of soil organic matter and nutritional status of crop plants is essential to sustain the production of organic farming systems. Thus, a 2–year field experiment was conducted to examine the effects of soil additions (192 kg N ha^–1, humic+192 kg N ha^–1, humic+144 kg N ha^–1 and humic+96 kg N ha^–1) and foliar applications (amino acids, Azotobacter+yeast, and amino acids plus Azotobacter+yeast) as various fertilizer resources on growth and yield of wheat. Results showed that humic+192 kg N ha^–1 × amino acids plus Azotobacter+yeast were the effective combination for producing the highest values of flag leaf area, total dry weight, tiller number m^–2, spike weight m^–2, and grain yield ha^–1. Under foliar application of amino acids plus Azotobacter+yeast, reducing N supply from recommended rate (192 kg N ha^–1) to 144 kg N ha^–1+ humic achieved higher values of all yield traits, with a saving of 25% of applied mineral nitrogen as well as enhancing nitrogen use efficiency.     

Phosphate adsorption by Na−, Mg− and Ca−saturated soil clays

Phosphate adsorption by the homoionic clay (Na, Ca, Mg) of three soils with widely varying mineralogy obeyed the Langmuir isotherm. The Langmuir constants b and k were a function both of the nature of the dominant clay mineral present and of the saturating cations following the order: Ca⁺⁺ ? Mg⁺⁺ ? Na⁺. This order was in agreement with those predicted by the diffuse double layer theory. The sample having montmorillonite when saturated with sodium, exhibited a negative adsorption of phosphorus which changed to a large positive adsorption in the presence of 0.1 N NaCl; It was concluded that the exchangeable cations influenced the extent of P adsorption by controlling the accessibility of the edge clay surfaces to phosphate ions.     

Alpha-tocopherol content in 62 edible tropical plants.

Vitamin E was determined by the high-performance liquid chromatography (HPLC) method. All the plants tested showed differences in their alpha-tocopherol content and the differences were significant (p < 0.05). The highest alpha-tocopherol content was in Sauropus androgynus leaves (426.8 mg/kg edible portion), followed by Citrus hystrix leaves (398.3 mg/kg), Calamus scipronum (193.8 mg/kg), starfruit leaves Averrhoa belimbi (168.3 mg/kg), red pepper Capsicum annum (155.4 mg/kg), local celery Apium graveolens (136.4 mg/kg), sweet potato shoots Ipomoea batatas (130.1 mg/kg), Pandanus odorus (131.5 mg/kg), Oenanthe javanica (146.8 mg/kg), black tea Camelia chinensis (183.3 mg/kg),papaya Carica papaya shoots (111.3 mg/kg), wolfberry leaves Lycium chinense (94.4 mg/kg), bird chili Capsicum frutescens leaves (95.4 mg/kg), drumstick Moringa oleifera leaves (90.0 mg/kg), green chili Capsicum annum (87 mg/kg), Allium fistulosum leaves (74.6 mg/kg), and bell pepper Capsicum annum (71.0 mg/kg). alpha-Tocopherol was not detected in Brassica oleracea, Phaeomeria speciosa, Pachyrrhizus speciosa, Pleurotus sajor-caju, and Solanum melongena.     

Antigenic types of bluetongue virus prevalent in Egypt

Summary In an attempt to identify the antigenic types of bluetongue (BT) virus prevalent in Egypt 31 selected sheep sera from different parts of Egypt which had been screened by gel precipitation tests were examined by a plaque reduction test using 16 types of BT virus. Dilutions 1:5 of those screened sera reduced more than 50% of plaques of at least 1 of 16 types of BT virus. Two sera completely inhibited plaque formation with type 4 virus, 1 with type 13, another serum with type 15 and 2 other sera with type 16 virus. The significance of the above serological findings is discussed.

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Tipos Antigenicos Del Virus De Lengua Azul En Egipto

Resumen Se examinaron 31 sueros seleccionados de ovejas de diferentes partes de Egipto. La prueba utilizada fué la de reducción de placas usando 16 tipos de virus de lengua azul. Los sueros habían sido examinados previamente mediante la prueba de precipitación en agar. Las diluciones 1:5 de los sueros examinados previamente, redujeron más del 50% de placas de por lo menos 1 de 16 tipos de virus de lengua azul. Dos de los sueros inhibieron completamente la formación de placas con el virus tipo 4, 1 con el tipo 13, otro suero con el tipo 15 y dos más con el tipo 16. Se discute el resultado de las pruebas serológicas.

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Types D'Antigenes Du Virus De La Blue Tongue Existant En Egypte

Résumé Pour identifier les types antigéniques du virus de la Blue Tongue existant en Egypte, 31 sérums de mouton provenant de diverses régions du pays, préalablement examinés par immunoprécipitation en milieu gélifié, ont été soumis à un test de réduction des plages avec 16 sérotypes du virus. Les dilutions au 1/5 de ces sérums ont réduit les plages de plus de 50 p. 100 pour au moins un des 16 sérotypes.Deux sérums ont complétement inhibé la formation des plages avec le type 14, avec le type 13, un autre avec le type 15 et deux enfin avec le type 16.La signification de ces résultats sérologiques est discutée.