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| Registros recuperados: 22 | |
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| Bergeron, Jean-pierre. |
| An elementary theoretical argumentation is advanced in favour of a global approach of some aspects of mesozooplanktonic systems dynamics and specially their production potentialities. For this purpose, measurements of the activity of aspartate transcarbamylase (ATC), an enzyme contributing to biosynthesis of basic components of nucleic acids, are performed on samples of the whole mesozooplankton. The method is applied to the neritic community of the North coast of Brittany (Western English Channel) during the productive period of springtime. The development of ATC activity during the increase of the mesozooplanktonic biomass shows global characteristics similar to those of organisms. The coherence of this result is analysed in connection with prior data. |
| Tipo: Text |
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| Ano: 1983 |
URL: http://archimer.ifremer.fr/doc/00246/35766/34279.pdf |
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| Bergeron, Jean-pierre. |
| In temperate neritic areas, meteorological conditions prevailing during winter and the following spring play a major role on the main features of the spring development pattern of pelagic ecosystems. Interannual fluctuations of this environment lead to qualitative and quantitative variations of secondary production which may strongly influence processes regulating the recruitment of many species. A method for assessing pelagic secondary production is based on measurement of the activity of an enzyme, aspartate transcarbamylase, and has been carried out during spring periods for six years in succession, in the southwestern part of the English Channel. These works have permitted the establishment of a close correlation between the quantitative variations of... |
| Tipo: Text |
Palavras-chave: ASPARTATE TRANSCARBAMYLASE; ENGLISH CHANNEL; RECRUITMENT; DOVER SOLE; ZOOPLANKTON. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00072/18303/15883.pdf |
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| Bergeron, Jean-pierre; Masse, Jacques. |
| Fishermen have long observed the sudden change of shoaling behaviour of small pelagic fish following a strong wind event. The phenomenon was thereafter confirmed by fisheries scientists using acoustic tools. In this study, we report our observations made with acoustics to measure disorganization of the previously observed spatial distribution and shape of shoals that occurred after a wind event. The measurements were made during a fisheries research cruise in the Bay of Biscay (NE Atlantic) aimed at determining i) small pelagic fish species abundance and ii) the individual nutritional state of anchovies (Engraulis encrasicolus L.) via evaluation of their RNA/DNA ratio. A spatial fine-scale study was conducted in two of the main breeding areas for anchovy,... |
| Tipo: Text |
Palavras-chave: Engraulis encrasicolus L.; Anchovy; Behaviour; Acoustics; Bay of Biscay; Nutritional condition; RNA/DNA ratio. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00033/14473/11782.pdf |
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| Bergeron, Jean-pierre. |
| A major spawning ground of the European anchovy (Engraulis encrasicolus) population in the Bay of Biscay is located near the mouth of the Gironde estuary. Variations in the river discharge affect the supply of nutrients to the coastal marine area encompassing anchovy spawning grounds. Two "Pegase" cruises (May-June 1997 and 1998) observed two contrasting situations: with and without a superficial layer of less saline water. Two new nutritional indices were used to assess potential effects (1) on carbohydrate assimilation rates by zooplankton estimated via pyruvate kinase (PK) activity measurements and (2) on nutritional condition of the anchovy larvae measured with the DNA/C index. Both indices indicated a much poorer situation in 1997 compared to 1998.... |
| Tipo: Text |
Palavras-chave: River outflow; Pyruvate kinase; DNA/C index; Bay of Biscay; Anchovy larvae. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-448.pdf |
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| Bergeron, Jean-pierre; Delmas, Daniel; Koueta, Noussithe. |
| In the 2000 and 2001 springtime periods, mesozooplankton samples were systematically taken during research cruises devoted to the study of the distribution and abundance of small pelagic fishes in the French part of the Bay of Biscay, NE Atlantic, continental shelf. Simultaneous activities of three enzymes were measured in these mesozooplankton samples, to characterize the main features of ecosystem function at a regional scale. The aim was to assess assimilation rates of carbohydrates, through pyruvate kinase activity, and protein, through trypsin activity, by the mesozooplankton community and the resulting overall productivity, through aspartate transcarbamylase activity. The highest influence on the pelagic environment was the strong difference in the... |
| Tipo: Text |
Palavras-chave: Rivers discharge; Phytoplankton distribution; Anchovy; Nutritional state; RNA/DNA ratio; Mesozooplankton; Metabolic descriptors; North-East Atlantic; Bay of Biscay. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00012/12290/9089.pdf |
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| Richard, P; Bergeron, Jean-pierre; Boulhic, M; Galois, Robert; Person, Jeanine. |
| Using analyses of individuals, dry weight, RNA, DNA and protein content were measured on the same samples to assess the nutritional status of laboratory-reared larvae and juveniles of Solea solea (L.). During the early life of S. solea, 2 growth periods could be distinguished by dry weight measurements and biochemical composition analysis. After metamorphosis, dry weight, RNA, DNA and protein content per individual increased more slowly than before metamorphosis. RNA, DNA and protein were strongly positively correlated to dry weight of fed larvae. Starvation led to immediate loss of weight and to decrease in RNA and protein content, while DNA amount per individual remained roughly constant. Percentage of protein relative to dry weight was always lower in... |
| Tipo: Text |
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| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00072/18304/15868.pdf |
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| Bergeron, Jean-pierre. |
| A new biochemical index was used to assess larval fish nutritional condition during a. survey cruise in the Bay of Biscay in early June 1993. This period corresponds to the breeding season of the European anchovy (Engraulis encrasicolus L.). The analysis of samples taken at grid points indicated a clear spatial pattern in nutritional condition, which increased from the middle shelf to the shelf edge. A relatively large fraction of the larval population proved to be in poor condition. Strong winds with speeds of 20-30 knots occurred during 3 d after the first survey and affected the vertical hydrological structure. During a subsequent survey, samples taken at approximately the same locations showed that anchovy larvae in all areas were in very poor... |
| Tipo: Text |
Palavras-chave: Windstress; Nutritional condition; Fish larvae; European anchovy; DNA/C; Bay of Biscay. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-449.pdf |
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| Gilliers, Camille; Le Pape, Olivier; Desaunay, Yves; Bergeron, Jean-pierre; Schreiber, Nathalie; Guerault, Daniel; Amara, Rachid. |
| Indicators of growth and condition were used to compare the habitat quality of nurseries of juvenile sole (Solea solea L.) in the Bay of Biscay, based on one survey in 2000. The four biological indicators are poorly correlated with each other, suggesting that no single measure may give an adequate description of fish health and of its habitat's quality. Growth indicators showed significant differences between northern and southern areas. Juveniles from the two southernmost nurseries, the Gironde estuary and the Pertuis Antioche, displayed significant lower otolith increment widths and mean sizes. These differences were inversely related to water temperature and unrelated to genetic or age differences, and are unlikely to be due to limiting trophic... |
| Tipo: Text |
Palavras-chave: Erika oil spill; RNA/DNA; Otolith daily increment width; Essential fish habitat. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3963.pdf |
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| Petitgas, Pierre; Masse, Jacques; Bourriau, Paul; Beillois, Pierre; Bergeron, Jean-pierre; Delmas, Daniel; Herbland, Alain; Koueta, Noussithe; Froidefond, Jean-marie; Santos, Maria. |
| The spatial pattern in hydro-plankton and fish distributions and their relationship were analysed based on the spring 2000 fisheries acoustic survey. The importance of this survey was that it was a multi-disciplinary platform which collected an extensive set of parameters in the hydro-plankton leading to a potentially finer description of hydro-plankton conditions and fish habitats. More than 50 variables were measured on a grid of stations, in four compartments of the ecosystem: hydrology, nutrients, primary producers and meso-zooplankton. First, a joint analysis of all hydro-plankton compartments was performed using multiple factor analysis (MFA). The method was used to estimate a compromise factorial space common to all compartments in which the... |
| Tipo: Text |
Palavras-chave: Fish environment relationship; Hydro plankton; Habitats; Multiple factor analysis; Spatial pattern. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-3961.pdf |
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| Bergeron, Jean-pierre; Buestel, Dominique. |
| The breeding cycle of scallops (Pecten maximus L.) from a population harvested in Bay of Saint-Brieuc has been surveyed over a period of three years with a classical gonad index, which is useful for the detection of the maturity and first spawning at the beginning of the season. Then phenomena are more complex with rematuration and late spawning.So we tried to find a new biochemical index and in 1977 the in situ sexual maturation of individuals from this population was studied simultaneously by measuring concentration of aspartate transcarbamylase (ATC), which was used as a potential index of gonad growth.A positive correlation was evident between this activity and the growth rate of the gonad.During the spawning period, the variations of ATC activity are... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5271.pdf |
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| Bergeron, Jean-pierre. |
| The study examines the spatial variations over the French continental shelf of the southern Bay of Biscay (North-East Atlantic) in the nutritional condition of anchovy (Engraulis encrasicolus L.) larvae which was estimated through their DNA/C index. The same cruise yielded quantitative estimates of two metabolic descriptors of the functioning of mesozooplanktonic communities, the enzymes pyruvate kinase (PK) and trypsin, for the first time evaluated simultaneously. The aim was to appraise quality and quantity of matter assimilated by the mesozooplankton and to specify whether the main components of prey ingested by copepods are principally carbohydrates, through PK activity, or protein, under the action of the digestive endopeptidase trypsin. The larval... |
| Tipo: Text |
Palavras-chave: Anchovy larvae; Bay of Biscay; DNA/C index; Mesozooplankton; Pyruvate kinase; Trypsin. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6473.pdf |
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| Bergeron, Jean-pierre; Herbland, Alain. |
| Estimates of carbohydrate assimilation within the mesozooplankton compartment are a fundamental concern in oceanography because they give a general expression of the biologically-regulated incorporation of metabolic fuel produced from inorganic nutrients by phytoplankton in the sea. A new tool is proposed for the assessment of such processes. It is based on the measurement of the activity of an enzyme, pyruvate kinase (PK), on samples of the whole mesozooplankton community. Here, the results are presented of an early attempt at such an implementation in the Bay of Biscay (north-east Atlantic) in springtime. A main area situated in front of an estuary (Gironde) has been extensively studied-the same sampling grid was covered on three occasions (two 20 day... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Zooplankton; Phytoplankton; Pyruvate kinase; Carbohydrate. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/publication-452.pdf |
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| Bergeron, Jean-pierre; Masse, Jacques. |
| The recruitment of marine fish populations is a central concern of fisheries scientists. Multiple research pathways have been explored, with emphasis of the causes of mortality affecting principally the early developmental stages of fish life. The small data set presented focuses on a feature often inadequately considered, i.e., the nutritional condition of the breeding parent fishes estimated from the levels of the RNA/DNA ratio determined in fish white muscle. This is applied to the European anchovy population inhabiting the French continental shelf of the North-east Atlantic Ocean. In four of the five years analysed, the annual recruitment shows a tight relationship with the mean values for the RNA/DNA ratio determined in the parent fish during the... |
| Tipo: Text |
Palavras-chave: Anchovy; Bay of Biscay; Breeding season; Recruitment; RNA/DNA ratio. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00109/22025/19684.pdf |
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| Registros recuperados: 22 | |
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