Risk-based zoning and siting for marine aquaculture

Spatial planning for marine aquaculture, including risk-based zoning and siting, is receiving increased attention, considering the increasing development of the aquaculture industry. It aims to ensure the most equitable use of the marine space for this activity, supporting production, minimising conflicts with other uses and maintaining environmental integrity.

Marine aquaculture zoning and siting through an ecosystem approach and considering climate variability and change is encouraged by FAO (FAO, 2018, FAO, 2017) as an important adaptation measure. Appropriate site selection supported by a flexible regulatory framework, is also suggested as adaptation strategy in case studies of the Horizon 2020-funded ClimeFish project, aiming to ensure that the increase in seafood production comes in areas and for species where there is a potential for sustainable growth, given the expected changes in climate. Risk-based zoning and siting can help avoiding areas particularly vulnerable to climate risks and selecting the most suitable areas for the cultured species, considering both the current state and the challenges posed by climate change in the medium-long term. The overall process allows minimizing possible economic losses that could derive from choices that do not take into account all risks and concerns.

Risk-based zoning and site selection is needed in areas both where aquaculture is beginning to develop and where aquaculture has already developed and its relocation is constrained by environmental issues and conflicts with other uses. A wide variety of spatial tools and models exists, as described in a dedicated FAO publication (FAO, 2017). New knowledge has been produced by the Aquaspace project (funded by the EU Horizon 2020 programme), which aimed to understand spatial and socio-economic constraints on the expansion of aquaculture and test tools to help overcome these constraints. Specifically, Aquaspace delivered a toolbox containing information on tools tested during the project, to help and support the purpose of making more high-quality space available for aquaculture. With the H2020 funded project TAPAS (Tools for Assessment and Planning of Aquaculture Sustainability), new research has been developing to promote and consolidate the environmental sustainability of the European aquaculture, also providing near-field models for site selection of aquaculture, using a series of existing, adapted and newly developed models.

Within the spatial planning process, the zoning step aims to identify broad areas potentially suitable for aquaculture, also referred as Allocated Zones for Aquaculture (AZA), in order to ensure integration of aquaculture into areas already exploited by other uses. Zoning should include a complete risk analysis identifying main threats to a successful production. Climate-related risks need to be taken into account as well to ensure success in the aquaculture business, considering that the sector is vulnerable to a number of potentially catastrophic climate disturbances. Climate risks include direct damages caused by severe waves, tidal and storm surges, as well as slow onset effects responsible for changing of physical-chemical conditions of seawater (e.g. increasing temperatures, acidification) and related indirect impacts such as disease diffusion, harmful algal blooms and hypoxia. Climate risks figure among other non-climate risks, related for example to the environment (pollution), health (biosecurity) and to social conflicts.

When broad zones suitable for marine aquaculture are defined, the siting step ensures that farms are located in a specific location with proper characteristics that enable a successful production. Through site selection the biophysical attributes of a site are compared to the needs of the selected organisms for culture and to the functioning requirements of farms. This assessment should include a review of local climate conditions (historical data), of risks posed by climate variability (e.g. storms) and of long term trends (e.g. rising temperature and change in salinity). The whole process of zoning and siting aims to minimise conflicts with other sectors and adverse impacts on the society, human well-being and ecosystem functions and services, according to the ecosystem approach to aquaculture development.