Downstream migration of juvenile European sturgeon Acipenser sturio L. in the Gironde estuary - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Accéder directement au contenu
Article Dans Une Revue Estuaries Année : 2001

Downstream migration of juvenile European sturgeon Acipenser sturio L. in the Gironde estuary

Eric Rochard
Mario Lepage
Serge Tremblay
  • Fonction : Auteur
Christine Gazeau
  • Fonction : Auteur
  • PersonId : 1207081

Résumé

The European sturgeon (Acipenser sturio) is an endangered diadromous fish species that spawns in the rivers in late spring and early summer. The juveniles spend their first years in the brackish waters of the estuary zone before moving out to sea. This study describes the downstreams migration pattern of juvenile sturgeon, belonging to the 1994 cohort, the only one born naturally in the Gironde basin since the end of the 1980s. During October 1994 to December 1996 the inland section of the Gironde estuary was sampled monthly by trawl and all European sturgeon caught were marked and released. The first sturgeon of the 1994 cohort were caught in early March 1995 in the zones furthest upstream. During their second fall of life, juveniles gradually acclimatized, and spread over a wide range of salinity conditions. A first incursion into marine water was also abserved by the end of the second winter. During this second period, sturgeon showed preference for two particular zones situated at 18 and 38 km, respectively, from the mouth of the estuary. These zones, belonging to two different salinity sectors of the estuary, did not appear to be any different to their neighbors with regards to depth and type of substrate. There were no significant size differences among estuarine zones. Seasonal movements of sturgeon seem to be motivated by a search for warmer temperatures. After a period of early acclimatization of 15 months, juvenile European sturgeon appear to be highly tolerant of salinity variations.
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Dates et versions

hal-02579648 , version 1 (14-05-2020)

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Eric Rochard, Mario Lepage, Pierre Dumont, Serge Tremblay, Christine Gazeau. Downstream migration of juvenile European sturgeon Acipenser sturio L. in the Gironde estuary. Estuaries, 2001, 24 (1), pp.108-115. ⟨hal-02579648⟩

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