The Importance of Water Quality to Scotland's Shellfish

Author: Rob Clunas (Business Analyst)

After recently attending the Association of Scottish Shellfish Growers annual conference in the Scottish town of Oban my eyes were opened to the delicate balance required between the economic, social and environmental issues faced by shellfish growers.

Shell and finfish are major economic players that support around 7000 jobs within Scotland, most of which are based in the Highlands and Islands. The environment and its protection is a major concern for the shellfish industry. Given the nature of filter feeders, farms must be located in waters free from pollution to ensure efficient growth and good health.

The industry’s current view is that shellfish improve water quality as they feed by filtering microscopic particles from the water. One oyster can process over 15 gallons of water each day, filtering particles as small as 2 microns. However, two recognised environmental issues caused by increased shellfish farming are carbon deposition and shell debris.

In the planning stages there is currently no legal requirement for impact environmental impact assessment (EIA), but the mood is changing and with the intensification of the use of our coastlines to grow fish produce, it likely that a clean environmental auditable practice will benefit those with a longer term vision.

However, even if an EIA is not a legal requirement, shore line assessment & some designated site specific investigations are. Given that every site varies, it is advised that you speak to a consultant in the initial planning stages of any project. Visual diver inspections alongside shore line assessments seem to be the standard assessment methods; there will be a greater need for survey within conservation areas or if the site is located near a priority marine feature - a designation given by Marine Scotland for a specific element of conservation importance.

For growth of the best, prime quality produce, it would be imperative to scope, define and monitor the quality of the water. There are various parameters that can be measured within water quality covering both physical (such as pH and dissolved oxygen), and chemical factors (heavy metal levels for example). By using the most up to date equipment and detailed chemical analysis, water quality monitoring can provide a clearer picture of the potential success of planned farms and the impact of existing farms.

Nevis Environmental can offer consultation, advice and surveys for shellfish, finfish and seaweed farms.