In order to fulfill EU strategies for reduction of fossil-based energy and to become a major player in sustainable aquaculture the MERMAID project aims to address the following key-questions:

• What are the best practices to develop a project on multi-use platforms?
• What are the accumulated effects of large scale structures on the marine environment?
• What are the best strategies for installation, maintenance and operation of a multi-purpose offshore platform?
• What is the economical and environmental feasibility of multi-use platforms?

Four offshore test study sites with different environmental characteristics have carefully been selected for their specific challenges. The sites, which represent different environmental, social and economic conditions, are located at four different seas:

1. The Baltic Sea - a typical estuarine area with fresh water from rivers and salt water.
2. The trans-boundary area of the North Sea-Wadden Sea - a typical active morphology site
3. The Atlantic Ocean - a typical deep water site
4. The Mediterranean Sea - a typical sheltered deep water site.

With the results form these studies, a verified procedure will be created to select the most appropriate design options for a given off-shore area. This procedure should be generic so stakeholders and end users can use it for marine planning strategies.