Upstream migration and reproductive patterns of a population of allis shad in a small river (L'Aulne, Brittany, France)

Type Article
Date 2006-04
Language English
Author(s) Acolas M3, Veron V2, Jourdan H3, Begout Marie-LaureORCID1, Sabatie M3, Bagliniere J.L.3
Affiliation(s) 1 : CNRS, IFREMER, UMR, Ctr Rech Ecosyst Marins & Aquacoles, F-17137 LHoumeau, France.
2 : Inst Amenagement Vilaine, F-56130 La Roche Bernard, France.
3 : INRA, UMR, F-35042 Rennes, France.
Source ICES Journal of Marine Science (1054-3139) (Elsevier), 2006-04 , Vol. 63 , N. 3 , P. 476-484
DOI 10.1016/j.icesjms.2005.05.022
WOS© Times Cited 26
Keyword(s) Small river, Reproduction, Biological features, Anadromous migration, Allis shad
Abstract The characteristics and activity of adult allis shad [Alosa alosa (L.)] were analysed during the last part of their upstream migration in the L'Aulne, a small river in Brittany, and during reproduction on a unique spawning ground downstream of an insurmountable dam. The age of the spawners ranged front three to seven years, females being larger and older than males. Population-level migration and reproduction were studied by counting the number of migrating fish, by estimating the sex ratio, and by counting the number of nocturnal spawning acts for three consecutive years starting in 2000. The influence of the environment, especially water temperature and discharge, was highlighted: temperature during migration may supplant the influence of water flow, although high flow could allow passage over the dam. Such factors partly explain the annual pattern of migration and reproduction during the spawning season. The study showed that the biological features and characteristics of this Population of allis shad in a small river were similar to those of western Atlantic stocks in large rivers. (c) 2005 International Council for the Exploration of the Sea.
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