Shellfish production area assessments

We assess and classify a production or relaying area based on a sanitary survey.

A shellfish production area or relaying area cannot be classified until an assessment of the sources of pollution has been carried out. Humans and animals can be a source of contamination for the production or relaying area.

Quantities of organic pollutants released into shellfish production areas can vary at different times of the year, so assessments need to take account of seasonal variance.

This can include:

• rainfall readings
• waste-water treatment

Circulation in the water affects how pollutants move around. We must also find out the characteristics of the circulation of pollutants in the production area using:

• current patterns
• bathymetry
• tidal cycle

A sampling programme of bivalve molluscs in the production area will be based on:

• the most accurate data from a number of samples over time
• a geographical distribution of the sampling points
• sampling frequency

The results of the analysis are as representative as possible for the area considered.

Sanitary surveys

Shellfish production and relay areas are affected by multiple sources of pollution. All new shellfish production and relay areas must have:

• assessments of the sources of pollution
• a representative monitoring point for sampling
• a sampling plan established

Applicants (the harvester) need to complete an application form in conjunction with the Local Authority to request for the classification of a new shellfish or relay area. This provides the initial information for a sanitary survey to be commissioned.

More information on the application process (including requirements before classification can be approved) and the application form can be downloaded from the Shellfish classification page.

After your shellfish classification application has been accepted, we will ask our contractor to carry out a sanitary survey.

Sanitary surveys may also be conducted;

• when needed for certain amendments to sampling points
• when evidence indicates the sources of faecal contamination may have changed
• if the last sanitary survey for the area was undertaken over 6 years ago

Information assessed during a sanitary survey

The information that will be assessed is:

• location and extent of the shellfishery
• type of shellfishery (species, method of harvest, seasonality of harvest)
• location, type and volume of sewage discharges
• location of river inputs and other water courses 
• agricultural and wildlife sources
• location of harbours and marinas 
• historical average rainfall by month
• any other potential sources of contamination
• existing microbiological data from water quality or shellfish monitoring undertaken in the same area or adjacent areas.

In most cases, new areas will also require a physical check of the site and potential sources of contamination. This is known as a shoreline survey.

Survey Reports and Monitoring Assessments

Between April 2017 and March 2020 an interim arrangement was in place for the assessment of new production areas to determine representative monitoring points (RMPs). An RMP is one monitoring point within a shellfish production area, which can represent a number of sites within that production area.

From April 2020, sanitary surveys have been commissioned, which consider a wider assessment of risk. These reports can be found below:

Northern Ireland:

England and Wales

• Sanitary Survey Reviews April 2020 - present
• Classification zone assessments April 2020 - present
• RMP assessments April 2017 - March 2020