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Koutsikopoulos, Constantin; Karakiri, M; Desaunay, Yves; Dorel, Didier. |
Otolith microstructure analysis of sole juveniles, Solea solea (0-2 groups) sampled in the Bay of Vilaine, Bay of Biscay, was carried out using scanning electron microscopy. Daily increment analysis showed two cases growth retardation, recorded as narrow increment deposition during the first weeks after transition to the bottom-dwelling mode of life. It is assumed that the observed growth retardation of 0-group sole in the summer of 1982 might have been caused by the oxygen deficiency recorded in the Bay of Vilaine at that time. The same observation in otolith microstructure during late spring 1986 might be associated with a strong cold freshwater discharge recorded in the sampling area that affected both water salinity and temperature. |
Tipo: Text |
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Ano: 1989 |
URL: https://archimer.ifremer.fr/doc/00482/59341/62140.pdf |
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Koutsikopoulos, Constantin; Herbland, Alain. |
The studies of the pelagic stages of Sole (Solea vulgaris , Quensel) in the northern part of the Bay of Biscay are strongly influenced by the recent concepts concerning the importance of the physical processes in the evolution of marine populations. The investigations of the linkage between water masses circulation and year-class strength started in 1986 with the deployment of 3 ARGOS satellite tracked drifters at different depths in parallel with the ichthyoplanktonic surveys. The trajectory of the 7 m drifter (tracking the water masses above the pycnocline) is related to the wind. This drifter leaves the sector of the study after 10 days. After 40 days of variable environmental conditions, the 34 m drifter (situated below the density gradient) was only... |
Tipo: Text |
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Ano: 1987 |
URL: https://archimer.ifremer.fr/doc/00482/59344/62138.pdf |
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Koutsikopoulos, Constantin; Petitgas, Pierre. |
It is often necessary to sub-sample plankton samples even if the precision of the estimation is thereby decreased. A methodological optimization is looked for. The variance depends on the procedure of construction of the aliquot (strategy) and the number of individuals counted (effort). The sub-sampling effort is allocated in a general context of repartition of the total effort between sampling and sub-sampling. This effort depends on the time consumed by the sub-sampling procedure, the volume of the aliquot and the number of individuals counted. For the same effort, a systematic procedure for the construction of sub-samples is more precise than a random one because it travels through the entire sample and is thus less dependent on the spatial distribution... |
Tipo: Text |
Palavras-chave: Plancton; Sous-échantillonnage; Effort; Précision; Plankton; Sub-sampling; Effort; Precision. |
Ano: 1990 |
URL: http://archimer.ifremer.fr/doc/00131/24259/22252.pdf |
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