The BioArgoMed-2018 cruise is the logical continuation of the Bio-Argo-Med-2015 cruise (which took place in May 2015), during which 11 BioArgo floats and 3 Argo floats were deployed. 4 BioArgo floats were also recovered in very good condition, which will allow their re-deployment during BioArgoMed-2018. During most deployments / recovers, a CTD survey was conducted, which allowed the test of several methods for biogeochemical sensor calibration. This work provided the definition of metrological "good practices", some of which are discussed internationally to become the reference for the global BioArgo network. The scientific objectives of the campaign have not changed: the maintain of a network of BioArgo floats in the Mediterranean, to ensure the good quality of the observations and to contribute to the improvement of the understanding of the biogeochemical cycles of the basin through the free and real-time availibility of data. After two waves of deployment since 2012, the BioArgoMed network is one of the densest and most efficient network in the global ocean in terms of data, as recently reported by Johnson and Claustre (2016). The national and international context of research in the Mediterranean allows us also to enrich the scientific objectives of the cruise. Indeed, following the INSU MISTRALS Mediterranean workshop (Marseille, October 2015), the second phase the MERMEX program (ie the marine biogeochemical component of MISTRALS) should focus on the Eastern Mediterranean, particularly in the PERLE experimental action. For the PERLE project, three large-scale campaigns in the Eastern Mediterranean will be requested during the period 2018-2019 (two at CNFH and one at SHOM). These 3 campaigns (PERLE-1, PERLE-2 and PERLE-3) are organized with the direct contribution of foreign partners, especially Italians (OGS, SZN, CNR), Greeks (HCMR) and Germans (GEOMAR, Kiel). In parallel, simultaneous observation actions will be initiated by Turkish partners (METU-Erdemli) along the Anatolian coast; and Israeli partners on the eastern side of the Levantine Sea.