Evaluating the Environmental Conditions Required for the Development of Offshore Aquaculture

Aquaculture is the cultivation of aquatic organisms, usually for the purposes of human consumption. Worldwide, fish and shellfish consumption is expanding. Globally wild fish stocks are in decline and aquaculture is rapidly growing in importance. Aquaculture production will continue to support the increasing human demand for seafood to feed both mass and quality markets in different regions of the world.

Aquaculture is an increasingly important industry for the UK with exports worth in excess of £500 million. Most UK aquaculture occurs on the Scottish West coast with the dominant cultivated species being Atlantic salmon (Salmo salar) which accounts for 98% of Scottish marine finfish aquaculture. The industry has an export value in excess of £500 million and employs more than 8,000 people mostly in remote locations where other job opportunities are scarce.

Currently most aquaculture production occurs in fjordic sea lochs that provides relatively sheltered conditions for the farms. Industry and government have a desire to expand aquaculture production in Scotland but the opportunity to increase capacity within the sea loch environment in limited. Barriers to further expansion include planning issues, the transfer of parasitic sea lice that negatively impact fish health from one site to another, biomass limits imposed by the environmental regulator SEPA to minimise chemical and particulate impact, and the impact of fish killing harmful algal blooms that can be particularly acute in restricted exchange environments such as fjords. The fish farming industry also faces an ongoing battle with environmental campaigners who fear that intensive farming in lochs and fjords is damaging to wild stocks and ecosystems.

The development of aquaculture in "offshore" environments outside of sea lochs offers a potential route for the sustainable expansion of the industry. Such locations are still within the coastal marine environment but in more open and exposed water. More dispersive open environments potentially minimise the problems outlined above with the potential for larger farms with reduced inter connectivity and environmental impact. However, these more exposed environments will carry their own risks, for example in terms of potential storm damage.

To proceed with the development of offshore aquaculture a better scientific understanding of its potential benefits is therefore required. To achieve this, this project will use a combination of experimental observation at existing and proposed fish farm locations of contrasting exposure, along with previously unavailable industry data to validate existing and new physical and biological mathematical models. These models will then be used to evaluate the potential to reduce sea lice infections, the harmful algal bloom risk, the risk of equiment failure and the impact on farmed fish health of operation in more energetic environments.

There is a demand to increase the capacity of UK finfish aquaculture. However, development is limited by the lack of further suitable farm sites within the fjordic sea lochs of the Scottish west coast where the majority of the industry is based.

Fjords provide relatively sheltered conditions but the necessary relative proximity of farms facilitates and the restricted water exchange to the open sea generates a number of issues. These include the easy transfer between farms of parasitic sea lice, the SEPA biomass limit, planning issues and the impact of harmful algal blooms.

Locating fish farms in more exposed "offshore" locations still in coastal waters, but outside of the fjords, offers a potential solution to the problems of fjord-based working: offering the opportunity for greater distances between farms and greater dispersion of organisms (sea lice and HABs) and contaminants. Hence likely allowing the development of larger farms with improved fish heath.

However, a move "offshore" will require significant industry investment and requires science based underpinning. This project will therefore bring together a consortium of physical, environmental, biological and modelling based scientists, a major aquaculture company and stakeholders with interests in regulation and insurance of the industry to test the hypothesis of the benefits of offshore aquaculture operation.

The project will use new physical oceanographic measurements in tandem with historical and new industry collected fish health data to validate and where necessary improve biophysical models. We will establish a numerical wave model for the region. This will be combined with existing FVCOM based unstructured grid physical models that are coupled with biophysical models of sea lice dispersion, contaminant dispersion and harmful algal bloom advection and growth.

Application of these models will allow assessment of the suitability for aquaculture of more or less energetic environments.

The main impact goals of this project are:

- To provide a balanced evaluation of a number of key issues affecting offshore aquaculture development prospects: improving scientific understanding of the coastal environment and fulfilling the need for scientific evidence on a topic
which has been discussed for some time by the industry.
- To provide cost savings for industry, investors and isurers by enabling more informed development decisions.
- To allow regulators to develop coherent regional and national plans for development and expansion of the industry.
- To enhance community understanding of issues related to development of the aquaculture industry, allowing more informed responses to local development opportunities.

The main stakeholders that will derive benefit from this work are:
- Aquaculture site operators and investors, who will benefit from enhanced understanding of the environment in which they are planning to operate, and the risks, challenges and benefits that working in different locations may
present. Marine Harvest Scotland (project partner) are directly involved in all work packages of the project, and findings will be disseminated more broadly to stakeholders via regular fact sheets, workplace seminars and workshops.
- Marine Scotland (project partner), who will gain validation for existing models allowing applcation of these models to specific industry challenges, and gain context for development of future policy on aquaculture development.
- Crown Estate Scotland (project partner), who are involved in leasing for fish farm developments, and wish to better understand the future trajectory of the industry.
- Insurers (WillisTowersWatson, project partner) will gain a firmer footing for decisions on risk levels applying to developments across the breadth of environments occupied by the industry.
- Other governmental and regulatory bodies, such as Scottish Natural Heritage and SEPA. These institutions will gain insights into the dynamics of the coastal ecosystem, the dispersion of effluents and parasites, and the limitations
of current modelling techniques applied to this environment.
- The public, who will gain a clearer understanding of the benefits and costs (ecologically, financially and socially) of offshore aquaculture developments in comparison to near shore developments, via partners' web sites, fact sheets,
news reports and Twitter.