SARF053: A systematic assessment of the environmental impact of Scottish shellfish farms including benthos, water column and relevant special interactions

Start Date: 01/03/2009
End Date: 28/02/2011
Main Contractor(s): Scottish Association for Marine Science
Other Sponsor(s): The Crown Estate

Objectives

  Objective 1 . A comprehensive literature review to consider both published and 'grey' sources with regard the impact of shellfish farms. This Task will also involve liaison with existing Scottish shellfish farmers to better our understanding of up-to-date farm practices and how this may relate to environmental interactions.

Objective 2. Construct an ArcGIS database that combines habitat maps, the locations of shellfish farms and sidescan data to identify appropriate sampling sites.

Objective 3. We aim to side-scan survey 10 farms in order to facilitate hypothesis development and site selection. Further acoustic mapping, to refine imaging of previously surveyed farms or to focus on particular areas, will continue in conjunction with other surveys (see Objective 5).

Objective 4. The development of DEPOMOD-shellfish, including model parameterisation from published data. The model will be further refined by inclusion of data from Objective 5

Objective 5. To establish the relationship between distance from shellfish farm, sediment characterisitcs and macro- and megabenthos we will sample using a drop-down camera, a Van-veen grab and a Craib corer (depending on the penetrability of the seabed). This will enable us to enumerate the macro- and megabenthic response to shellfish farm proximity. Surficial sediment samples for analysis (organic carbon, carbon/nitrogen ratios and particle size) will be taken and linked to the macro- and megafaunal communities.

Objective 6. Collation and analysis of 17 years of archived algal community data to examine changes in algal community pattern occuring before and after the introduction of large-scale mussel farming in Lochs Creran and Spelve. These community changes will be used to test and develop the LESV-ACExR model.

Summary

At present the environmental effects of shellfish farms are largely unregulated, although there is clear regulation relating to shellfish growing waters and potential disease organisms and toxins in the product. There has been relatively little research on this topic in Scotland but it has received some attention in several other countries. In order to inform policy to ensure the sustainable development of the industry, it is necessary to carry out a focussed assessment of potential impacts via appropriate reseach at a range of sites encompassing environmental conditions typical of the Scottish industry. In particular we need to a) assess whether farms cause sufficient impact to warrant regulation and b) if so to propose appropriate and cost-effective impact prediction and regulatory mechanisms and c) in conjunction with existing work to provide model parameters related to 'sealoch scale' ecosystem effects.