Contribution à l'étude de la croissance de la fougère aquatique Salvinia molesta (Mitchell), Salviniaceae

The growth of the primary and the tertiary forms of the water fern Salvinia molesta was studied during 60 days in 0.06 m2 glass containers containing fresh water. The growth of this plant as a function of time is exponential. The two forms have growth rates statistically identical. The main daily growth rate, expressed in number of leaves, is equal to 6.40% per day for primary forms and 5.90% per day for tertiary form, with doubling time of 10.78 + 1.08 days and 11.64 + 0.15 days.

Étude préliminaire sur l'incorporation de liants dans un aliment composé pour poisson d'élevage en Côte d'Ivoire

Artificial feeding constitutes a very important aspect for intensive fish culture. Then, the physical properties, particularly water stability of feed, wider influence the fish production. By trying to find some answers to these problems, a preliminary study on water stability has been conducted at the LAYO aquaculture research station. This work consisted in incorporating different types of binders available in tropical countries in fish pellets of 3.5 mm and 6.0 mm diameters in order to identify an efficient binder allowing the improvement of the water stability of feed. From this experiment, it comes out that the use of wheat flour (A1) gives excellent quality pellets followed by cassava flour residue (A3). Moreover, this study shows that it exists an influence of the diameter on the crumbling of the pellets.

Contribution à l'étude des caractéristiques morphologiques de l'unité littorale de Côte d'Ivoire, Golfe de Guinée: cas du périmètre littoral de Port-Bouet

This paper presents a large scale (1/10000) bathymetric chart along with the beach (s.l.) and shoreface schemes of Port-Bouet littoral. All these charts and maps contributed to identify the three morphological sub-areas which characterize the whole littoral area of Port-Bouet.

Variations saisonnières des facteurs hydrologiques et du biovolume microalgal benthique au sein d'un habitat artificiel (acadja-enclos) dans la lagune Ebrié: site d'Adjapoté

This paper presents the results of a comparative study of chemical and physical characteristics (temperature, oxygen, salinity, turbidity, pH, nutrient: phosphates, nitrates, nitrites, ammoniac) within the extensive aquaculture structure (acadja-enclosure or artificial habitats for fishes) and in the surrounding water. Biological characteristics of the periphyton growing on bamboos from acadja-enclosure were also described.

Statistiques de pêche en Lagune Aby (Côte d'Ivoire): évolution de l'effort et des captures de 1979 à 1990

Two kinds of fishing gears insure the exploitation in Aby lagoon: the individual gears are represented essentially by gill nets and collective gears by seines. The number of gill nets varies between 1500 in 1981 and 5600 in 1986. The beach seines, which number varies between 40 and 60, are regularly used. The purse seines (15-30) have been superseded by "syndicat" seines (15) in 1990.

显微成像荧光屏用无机闪烁单晶薄膜的研究进展

随着第三代同步辐射源的出现，由荧光屏和CCD耦合组成的、具有亚微米级空间分辨率、快速在线成像功能的探测器在医疗、安检、工业、科研等领域将会得到广泛应用．本文主要综述了成像荧光屏用材料的概况和发展趋势，重点阐述了闪烁单晶薄膜的研究及发展情况．

Investigation of the spectroscopic properties of Yb3+-doped yttrium lanthanum oxide transparent ceramic

Spectroscopic properties of (Y0.9-xLa0.1Ybx)(2)O-3 transparent ceramic were studied. Two main absorption peaks of the specimen are centered at 940 and 970 nm, which are suitable for InGaAs laser diode pumping. The main emission peaks were located at 1032 and 1075 nm with larger emission cross-section and longer fluorescence lifetime than those of Yb:Y2O3. These properties of (Y0.9-xLa0.1Ybx)(2)O-3 transparent ceramic are favorable to achieve high efficiency and high power laser output. (c) 2007 Elsevier B.V. All rights reserved.

Linefish resources annual report for the year 2000. Part 3: towards a management plan for the Mozambican line fishery

The dependence of Mozambique on its marine resources is highly significant. There is a need for a plan of action for sustainable use of these important resources, for the benefit of the nation. In this document, some aspects are included, that can be important to take into consideration for a sound action plan for the lin fishery of Mozambique.

Rélation longueur céphalothoracique-poids total chez Penaeus duorarum (Burkenroad) en Côte d'Ivoire

This short note gives the results of the measurements of cephalothoracic length-total weight of Penaeus duorarum in Côte d'Ivoire and compares those data to the ones collected in Senegal (Bondy 1968) and in the Gulf of Mexico (Kutkuhn 1965).

La pêche crevettière en Côte d'Ivoire. Bilan 1969-1970 et perspectives

The evolution of the fishery of the pink shrimp Penaeus duorarum Burkenroad is analysed from its beginning in 1969 until the end of 1970. A rapid and general decline of the yield has been evident during this period. The actual shrimp fleet seems to be too big to allow an exploitation economically convenient of the stock.

La pêche au chalut en Côte d'Ivoire. Maximum de rendement économique

This paper analyses the relations between effort and catch per unit effort of trawlers which worked in Côte d'Ivoire from Jan 1966 to Dec 1970. A fishing effort permitting to exploit fishery in the best rentability conditions is proposed.

Biologie et dynamique d'un Sciaenidae ouest-africain Pseudotolithus senegalensis (V.)

In relation to the hydroclimate prevailing off Congo (B) and Côte d'Ivoire, synchronic variations are described in abundance and distribution of Pseudotolithus senegalensis V., economically the most important species in the West African trawl fishery. Although this fish prefers the warm surface layer, it is relatively indifferent to hydrological conditions, since it may also occur in the thermocline down to the higher levels of 'Central South Atlantic Water'. The oxygen concentration appears to have an important effect upon their distribution, especially the low concentrations occurring with the upwelling. The main biological functions, such as spawning and recruitment times, condition factor, diet and ring appearance on otoliths, also follow cycles, which are parallel with the hydroclimate one. Therefore, the ring-shaped structures revealed by burning previously ground otoliths could be easily interpreted. Thus, an accurate method for ageing tropical fish is now available. From the age determinations for the Congolese stock, it appears that growth is fast and total mortality rate high. An influence of fishing effort, which increased 3 times during the exploited phase of sampled specimens, appears both in growth and in total mortality. From there an estimate for the fishing mortality could be given. The estimates of dynamic parameters for the Congolese stock are then used in the Beverton-Holt model. A valuable increase of the yield could be expected, if mesh size is widened and effort restricted.

Standardisation des efforts de pêche des chalutiers ivoiriens et estimation de l'abondance relative dans les divers secteurs

The method developed by Robson (1966) is used to standardize fishing effort of Côte d'Ivoire trawlers whose size and power are very different. This method also allows the estimation of the relative abundances in the different fishing areas. The results obtained using 10 years data show that the entire Ivorian continental shelf can be considered as a single fishery unit. The relative fishing power of vessels is well correlated with gross tonnage, brake horse power and length of the vessel. The obsolescence of the trawlers affects their fishing power.