Colonization by marine ichtyoplankton on mudflat in the Gironde estuary - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Accéder directement au contenu
Poster De Conférence Année : 2012

Colonization by marine ichtyoplankton on mudflat in the Gironde estuary

Colonisation des vasières de l'estuaire de la Gironde par l'ichtyoplancton marin

Résumé

Restoring fish habitats in estuaries is at present a major concern for stakeholders. In the Gironde estuary, as in the others, projects of port and industrial developments which require direct access to waterways often require the creation of embankments destroying habitats for fishes. Estuaries wetlands such as intertidal mudflats and marshes provide numerous ecological services and act as essential habitats for many species and this, from the youngest stages of development. Actually, many larvae of marine species whose eggs hatch at sea colonize the estuary and especially the mudflats of the latter via the tides. There they settle for short period, they feed and grow. To better understand the importance of these habitats for fish species, surveys are conducted to collect ichthyoplankton with bongo-type net and bottom frame-trawl net (mesh size 500 μm for both nets) from the intertidal mudflats. Samples of larvae are collected, throughout the water column, once a month from Marsh to June 2012, in different mudflats of the Gironde estuary using a 7m fishing craft with 40cm draft. Each sampling site on the left shore has its geographical equivalent on the right shore. Identification to the species level, counting and measuring of individual lengths are performed. The abundance of larval populations using these habitats is estimated and the species composition is compared in order to identify if the species are similar on each side of the estuary. Furthermore, differences in size classes are expected. Indeed the larvae belonging to the younger developmental stages will be more passive that older larvae with regards to tidal current. Because ichthyoplankton is highly subject to strong currents entering the estuary, data will be crossed to the outputs of a hydraulic model to explain eventual differences in the distribution of larvae and the colonization of the estuarine mudflats by marine larvae. The restoration of intertidal and subtidal mudflats requires knowledge of all the ecological roles of these ecosystems. This study will provide essential knowledge about the ecological roles of different mudflats of the estuary towards the populations of larvae originating in the Atlantic Ocean and will give information on where restoration action should be taken as to maximize the potentialities of new settler fish larvae.

Mots clés

Fichier principal
Vignette du fichier
pub00052709.pdf (4.13 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-02605479 , version 1 (16-05-2020)

Identifiants

Citer

V. Andreola, Mario Lepage. Colonization by marine ichtyoplankton on mudflat in the Gironde estuary. 36 th Annual Larval Fish Conference, Jul 2012, Bergen, Norway. pp.1, 2012. ⟨hal-02605479⟩

Collections

IRSTEA INRAE
15 Consultations
9 Téléchargements

Partager

Gmail Facebook X LinkedIn More