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International audience; This paper looks at experiential feedback and the technical and scientific challenges tied to the MERITE-HIPPOCAMPE cruise that took place in the Mediterranean Sea in spring 2019. This cruise proposes an innovative approach to investigate the accumulation and transfer of inorganic and organic contaminants within the planktonic food webs. We present detailed information on how the cruise worked, including 1) the cruise track and sampling stations, 2) the overall strategy, based mainly on the collection of plankton, suspended particles and water at the deep chlorophyll maximum, and the separation of these particles and planktonic organisms into various size fractions, as well as the collection of atmospheric deposition, 3) the operations performed and material used at each station, and 4) the sequence of operations and main parameters analysed. The paper also provides the main environmental conditions that were prevailing during the campaign. Lastly, we present the types of articles produced based on work completed by the cruise that are part of this special issue.

This investigation aims at assessing patterns of spatial genetic structure of the teleost fish Sardina pilchardus across the Siculo-Tunisian Strait (a well-known discontinuous biogeographic area) a...

Engraulis encrasicolus is of great economic importance in the Mediterranean. However, little is known about its stock structure. Otolith shape analysis has been successfully used for fish stock identification. In this study, the stock structure of anchovy caught off the open sea and the coastal area of the Gulf of Tunis, lagoon of Bizerte and Lake of Ichkeul were investigated using otolith shape. Otolith shape was determined by Fourier analysis and then compared among specimens sampled from different areas with forward stepwise canonical discriminant analysis. Significant differences in otolith shape between the open sea and inshore anchovy groups were detected. Otolith shape of anchovy collected in the Lake of Ichkeul was distinct from the other groups. This finding suggests a clear discreteness of the open sea and the continental groups. The data highlighted the potential for using otolith shape analysis for anchovy stock identification, as well as the role of oceanographic features in determining stock separation. These findings will have major implications for anchovy fisheries management in Tunisia. By using a precautionary approach and considering the three areas as separate stocks, fisheries management strategies should be adjusted to achieve optimum sustainable production from each stock and to avoid decreases in genetic variety.

Our knowledge for the distribution of Atlantic mackerel (Scomber scombrus) in the Mediterranean Sea is limited and fragmented. In the current work habitat suitability modeling was applied to summer acoustic surveys data of Atlantic mackerel juveniles derived from the north part of the Mediterranean (i.e., acoustic data from the Gulf of Lions, pelagic trawls held during acoustic surveys in Spanish Mediterranean waters, south Adriatic Sea, Strait of Sicily, and North Aegean Sea) using generalized additive models (GAMs) along with satellite environmental and bathymetry data. Bathymetry along with sea surface temperature and circulation patterns, expressed through sea level anomaly and the zonal component of the absolute geostrophic velocity, were the environmental variables best to describe nursery grounds. The selected model was used to produce maps presenting the potential nursery grounds of Atlantic mackerel throughout the Mediterranean Sea as a measure of habitat adequacy. However, the assessed potential nursery grounds were generally marked as “occasional,” implying that although there are areas presenting high probability to encounter Atlantic mackerel, this picture can largely vary from year to year stressing the high susceptibility of the species to environmental conditions. In a further step and toward a spatial management perspective, we have estimated and visualized the overlap between Atlantic mackerel and anchovy/ sardine juvenile grounds throughout the basin. Results showed that although the degree of overlapping was generally low, not exceeding 15% in general, this varied at a regional level going up to 30%. The potential of the output of this work for management purposes like the implementation of spatially-explicit management tools is discussed, SI

Cette etude consiste a identifier les typologies du changement organisationnel et leur impact sur l’evolution des competences du personnel des entreprises. Il s’agit du changement organisationnel evolutif, radical et de celui produisant le developpement des competences individuelles, le renouvellement, la destruction et le developpement des competences collectives. Nous avons teste ces relations aupres d’un echantillon de 42 entreprises industrielles tunisiennes. Un questionnaire, portant sur 31 variables, a ete adresse a des cadres intermediaires de ces entreprises. L’analyse factorielle des correspondances multiples (ACM) nous a permis de tester nos hypotheses de recherche.