Offshore-Aquaculture

The terms "Offshore, Open Ocean, Far out" are currently unknown or seldomly used terms within the German public. Recently, however, these terms have become common "catch-phrases" in North America and elsewhere. In an effort to cover the immense demand for seafood products, new regions further exposed from the coastal waters are sought to offer area potential. However, there are currently very few world-wide Open Ocean Aquaculture businesses operating commercially as it is an internationally emerging technology yet requiring extensive development and testing.

Our current research concentrates on "Open Ocean Aquaculture" (OOA) and aims to ascertain the economic feasibility of an offshore marine aquaculture structure in the North Sea.

In German territorial waters, offshore wind farms as a new stakeholder is in the process of setting up installations mainly in the Exclusive Economic Zone (EEZ) of the North Sea. More than 3000 wind-generators are planned for installation in the EEZ before the end of this decade. Up to now, 12-80 are in the process of being installed. These offshore wind farm installations offer themselves as a first possibility for OOA installation testing.
Germany considers the combination of environmentally-friendly wind-driven power generation with the environmental enhancement that extensive aquaculture offers as a very important opportunity for the development of a multiple resource use concept.

Background

Caused by the strong natural fluctuation of recruitment of mussels (Mytilus edulis) during the last years, research commenced in 2000 to assess, whether suspended culture technique could be deployed to collect and culture seed mussels on a commercially stable basis under the exposed conditions of the North Sea.
In a current research, scientists of the Research Centre Terramare could show that depending on the season, the maximum bivalve larval abundance can peak to 5 to 15 x 103 larvae per m3 water column. In their study, seed collection was carried out by deploying collectors down-current of wild mussel colonies. Recruitment on artificial substratum was very high even in years with no recruitment on natural plots. In such a year (2000) a mean of 70.000 blue mussel spat were recorded per meter collector.
In addition to the natural fluctuations of spat, there are also severe limitations to an increase in production on conventional sublitoral and intertidal bottom culture systems along the German coast. These relate mainly to the extensive conflicts between various coastal resource users, in particular the need for maintaining (extending) Marine Protected Areas (MPAs). Thus, the only option within the German national marine waters seems to be the expansion to more exposed (offshore) farming.