THALAMACOU
| Type | Oceanographic cruise |
|---|---|
| Ship | Thalia |
| Ship owner | Ifremer |
| Dates | 18/05/2011 - 15/06/2011 |
| Chief scientist(s) | EHRHOLD Axel  |
GEO-OCEAN - UMR 6538 Univ. Brest, CNRS, Ifremer, Univ. Bretagne Sud Place Nicolas Copernic 29280 Plouzané |
|
| DOI | 10.17600/11070160 |
| Objective | Several estimations which are not in good agreement with each other have already been made on stocks of kelp in the Molène archipelago. Professional harvesters have noted a strong inter-annual fluctuation in Laminaria digitata stocks on traditional harvesting grounds and may have to envisage increasing the amounts of Laminaria hyperborea stock they tap, although this requires using different technical means. Apart from the needs of the profession, acquiring knowledge about the health status of the beds of Molène is also one of the objectives of the PNMI national Iroise sea marine park, which involves a combination of optical (lidar), acoustic (multibeam and single-beam echosounders and interferometric sonar) and sampling in situ. In this context, the Agency for marine protected areas, through IFREMER's expertise, wants to map the distribution of the seaweed beds on the shelf of Molène and Ushant based on new acquisitions (optical and acoustic techniques and sampling) and a biomass approach. This requires fine knowledge of the underwater topography in the area in order to delimit the preferred substrates along with ground truthing (rocky zone) prior to predictive modelling studies on kelp. This new knowledge will contribute to giving the PNMI a tool for forward studies and strategic piloting. In this framework, the surveys performed during the THALAMACOU cruise provided reconnaissance of the morphology and the distribution of seabed types in the archipelago at depths between 15 and 60 metres. The THALAMACOU mission provides the offshore complement to the surveys conducted in September 2010 in shallow areas during the HALAMACOU cruise (RV Haliotis). This falls under Project 3: Operational habitat mapping (program 4). |
