We tested the hypothesis that the active vertical migration of the larvae of anadromous rainbow smelt (Osmerus n~ordax) observed in the turbid, well-mixed portion of the St. Lawrence Estuary is an adaptation to improve feedlng incidence by retaining larvae in productive, up-estuary waters. We documented the vertical distribution, diet and feeding incidence of larvae of 3 length classes over 4 tidal cycles at each of 3 stations located along the longitudinal axis of the upstream portion of the estuary. The percentage of smelt larvae with gut contents increased with larval length and with distance upstream for all 3 length classes. Vertical migrations of larvae were not related to feeding incidence in the vertical plane, except in the case of the smallest length class, indicating that active vertical migrations were not behavioral responses to vertical changes in prey availability. The predominance of calanoid copepods and freshwater cladocerans in the diets of larvae with the highest feeding frequencies and the predominance of mysids in the diets of larvae with the lowest feeding frequencies suggested that larvae were more successful feeding on copepods and cladocerans than on the larger mysids. Apparent tidal rhythmicity in diet and feeding success was largely due to the tidal displacement of water masses at fixed sampling stations. Feeding incidence at the 2 sampling stations situated within the maximum turbiditv zone was greatest in larvae advected from upstream at the end of ebbing tide. We conclude that active vertical migration of smelt larvae is an adaptation to maximize the longitudinal retention of high densities of larvae in a zone of high prey biomass.

-The eastern English Channel, the narrow channel of water separating northern France and southeast England is an area of intense human use of the array of resources concentrated into its relative small area. The vulnerability of living resources and their habitats brought together French and British maritime experts within a common project (called CHARM): to create an atlas of marine resource habitats in the eastern English Channel so as to provide planners and decision-makers with the necessary information to help managing the use of its living and non-living resources. This multidisciplinary and richly illustrated atlas provides abundant information on the legal framework and physical environment; benthic invertebrates, fish and their habitats; fishing activities; and a first attempt at developing a trophic network model (using ECOPATH software) and a marine conservation planning exercise (using MARXAN software, at a spatial resolution of 25 km 2 ). Although most of the data used were collected elsewhere, some were collected especially for the project. Similarly, most of the analyses performed on the data where entirely original for this geographical area. The CHARM atlas has significantly improved the knowledge about the eastern Channel while contributing to the recognition that such holistic or multidisciplinary approaches to exploited marine systems are necessary to efficiently and durably manage their resources use. Key words: Eastern English ChannelRésumé -La Manche orientale, ce bras de mer qui sépare l'Angleterre de la France, est une zone très riche d'un point de vue écologique et soumise à une forte utilisation anthropique d'une gamme de ressources concentrées sur une superficie relativement faible. La fragilité des ressources marines vivantes et leurs habitats a rassemblé des experts maritimes français et britanniques autour d'un projet commun (nommé CHARM) dans le but de réaliser un atlas des habitats des ressources marines de la Manche orientale. Cet atlas contient les informations nécessaires aux planificateurs et décideurs pour une meilleure gestion des ressources marines, vivantes ou non. Dans ce document pluridisciplinaire, richement illustré, on peut trouver des informations sur le cadre juridique et l'environnement, les invertébrés benthiques, les poissons et leurs habitats ; les activités de pêche ; et également sur le développement d'un modèle de réseau trophique a Corresponding author: andre.carpentier@ifremer.frArticle published by EDP Sciences 500 C.S. Martin et al.: Aquat. Living Resour. 22, 499-508 (2009) (utilisant le logiciel ECOPATH) et un premier exercice de planification spatiale de la conservation (utilisant le logiciel MARXAN, à une résolution spatiale de 25 km 2 ). Bien que la plupart des données aient été collectées en dehors du projet, certaines l'ont été spécialement pour le projet. De même, la plupart des analyses faites sur ces données sont entièrement inédites pour cette zone géographique. L'atlas CHARM contribue de façon significative à une meilleure connaiss...

ABSTRACT. The vertical distribution of Owenia fusiformis larvae was studied from pump samples in the eastern part of the Bay of Seine, English Channel. between 9 May and 9 June 1987. Only 1 massive larval cohort was present. Four planktonic stages of different duration were distinguished. The duration of total larval life was estimated to be about l mo. Larvae were located preferentially under the pycnocline. Larvae showed an ontogenic migration with an increase of the larval center of mass (ZCM) for each stage according to age. This migration was associated with the 2-layer circulation present in the study area. Stage 1 was principally present in the diluted surface layer and carried downstream. Stage 2 was located just above the depth where the seaward residual flow is null. Downstream transport of these larvae should have been lim~ted. Stages 3 & 4 were located below the level of no net motion and consequently were transported upstream. However, the vertical distribution of Stages 1 & 2 could be changed in relation to water column stratification. When the stratification was slight, these larvae were evenly distributed over the water column, whereas a strong stratification generated a larval concentration under the pycnocline. The depth of larvae in the water may have resulted from interactions between behavior and water column structure. Ontogenic migration and aggregation of Stage 2 larvae just above the depth where net residual flow is null played a basic role in larval retention in the eastern part of the Bay of Seine and should partly explain the spatio-temporal stability of the adults.

There is a growing interest in the development of offshore wind farms to provide a sustainable source of renewable energy and contribute to the reduction of carbon emissions. In parallel, there is a need to better understand the effects of these installations on coastal marine ecosystems and identify potential sea use conflicts, especially when the area is subject to access restrictions. This study investigated the