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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; 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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| 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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