The terms “offshore” and “open ocean” have been used to describe aquaculture sites that are further from the coast and/or in higher energy environments. Neither term has been clearly defined in scientific literature or in a legal context and the terms are often used interchangeably. These and other related terms (e.g., “exposed”, “high-energy”), refer to specific aspects of a site, usually the geographic distance from shore or infrastructure, or the level of exposure to an extended fetch leading to large waves and strong currents. The term "offshore aquaculture" has hitherto encompassed various perspectives, including technology, geographical location, legal jurisdiction, and more. To resolve the ambiguity in this term and understand its implications for current and future aquaculture, "offshore" should be resolved into two separate metrics: (1) Distance from shore and (2) exposure. Consequently, “offshore is defined by the distance from the shore while exposure can be applied as additional character or aspect of any site”.
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The ICES Working Group for Open Ocean Aquaculture (WGOOA) therefore established a need to define the terminology to reduce ambiguity for characterising these types of aquaculture sites or more precisely, to: 1) promote a common understanding and avoiding misuse for different classifications; 2) enable regulators to identify and designate the characteristics of a marine site; 3) allow farmers to be able to assess or quantitatively compare sites for development; 4) equip developers and producers to identify operational parameters in which the equipment and vessels will need to be operating; and 5) provide insurers and investors with better means to assess risk and premiums.
The United Nations Convention on the Law of the Sea (UNCLOS) delineates zones in which States are largely free to regulate aquaculture and other exploitation activities (e.g. inland and territorial waters, exclusive economic zones). Within this framework, different coastal states have developed policies and laws that specifically govern aquaculture. Neither UNCLOS nor national aquaculture laws, however, provide a precise definition of the term “offshore”. Such vague geographical concepts alone cannot aid in identifying, assessing, and geographically pinpointing suitable aquaculture sites.
The metrics of distance from shore and exposure are seen as a range rather than a specific threshold, allowing for a continuum. Distance from shore is readily quantified as distance from the baseline. To rigorously quantify the exposure, six indices were generated, which covered various oceanic parameters (i.e., water depth, water currents, wave height and period). The influence and interaction of the oceanic parameters were all considered using the indices to determine site characteristics. Two indices were selected for utilization on the analysis of sites based on their ease of use and applicability.
Finally, we applied these indices to their use in aquaculture with different species, technologies and in O&M. We also considered the costs of expanding aquaculture from protected to more exposed sites. The influence of these definitions on socio-economic aspects is addressed. Negative public discourses on the expansion of nearshore aquaculture are one of the most prominent aspects driving public opinion against aquaculture. Expansion of offshore aquaculture out of sight from the coasts is a major advantage. Finally, we suggest necessary research areas to enable the expansion of aquaculture activities to "offshore" and "exposed" waters.
This research has been supported by the institutes of the scientists involved. The resulting 8 publications were compiled within the framework of the WGOOA (Working Group on Open Ocean Aquaculture) of the intergovernmental scientific organisation ICES (International Council for the Exploration of the Sea - Copenhagen/Denmark). Likewise, this project was supported by the OLAMUR project with 25 partners from eight nations dealing with the issues of technical implementation in the wind farms, as well as site selection, LTA performance, environmental monitoring and much more. The OLAMUR project is funded by the European Union under grant number 101094065.