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| Spitz, Jérôme; Rousseau, Yann; Ridoux, Vincent. |
| In aquatic ecosystems, competitive interactions are occasionally described. Violent attacks on harbour porpoises by bottlenose dolphins were reported and it was proposed that this behavior could result from competitive interactions for food. This hypothesis implies that the two predators should share all or part of they prey range. In this work, we describe the diets of each predator in the Bay of Biscay and adjacent areas from stomach content analysis of stranded animals. The diet of the harbour porpoise was mostly composed of small schooling fish living close to the seafloor (98 percent by mass). The diet of the bottlenose dolphin was characterised by the presence of large specimens of demersal fish (91 percent by mass) and cephalopods. Several prey... |
| Tipo: Text |
Palavras-chave: North Eastern Atlantic; Tursiops truncatus; Phocoena phocoena; Diet; Top predator; Interference competition. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1986.pdf |
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| Brunel, Thomas; Boucher, Jean. |
| Synchrony in population fluctuations have commonly been observed among a variety of species. They are generally attributed to the effect of common environmental forcings on population dynamics. Here, we investigate long term synchrony in the recruitment variations of the North East Atlantic fish populations. A PCA (principal component analysis) was performed to extract the main patterns of variation. The most significant one reflects the synchronous decrease of the recruitment for the majority of gadoids populations, in the Baltic Sea, Kattegat, North Sea, Irish Sea and West of Scotland. The inverse pattern was observed for half of the herring populations. Plaice populations also exhibit synchronous recruitment trends, characterised by strong year classes... |
| Tipo: Text |
Palavras-chave: Synchrony; Regime shift; Recruitment variations; North Eastern Atlantic; Climate change. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-1145.pdf |
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