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Shellfish controls information

Shellfish production and how it is monitored and reported by us.

Last updated: 22 December 2017
See all updates
Last updated: 22 December 2017
See all updates

We are the Central Competent Authority (CCA) directly responsible for decisions in relation to the classification and official control monitoring of shellfish. We give advice on closure and re-opening of shellfish production and relay areas. 

Live Bivalve Molluscs (LBM) include:

  • oysters (pacific and native)
  • mussels
  • clams
  • cockles
  • scallops

Since these species are filter feeders they are susceptible to picking up and accumulating toxins, chemical or bacteriological contaminants from their environment.

To reduce the risk of contamination, these species can only be commercially harvested from classified production areas that are monitored.

There are treatments that shellfish must undergo to reduce the level of microbiological contamination in them and ensure they are safe for placing on the market.

It is also a requirement to monitor classified production areas for marine biotoxins, phytoplankton and chemical contamination.

Sampling for official controls is carried out by Local Authorities responsible for the area in where a shellfish bed is located. Under specific arrangements with appropriate verification it may also be undertaken by private contractors or cross border organisations in agreement with the FSA.

Approved official control laboratories carry out the specified testing and analysis of the samples. When sample results indicate that levels of contaminants are found to be above the maximum permitted levels, action is taken by your Local Authority.

Classification, monitoring and sampling

Shellfish production and relay areas must be classified according to the levels of microbiological contamination (E. coli) detected in flesh samples from the area.


Biotoxin and phytoplankton monitoring

Monitoring chemical contamination

Supplementary sampling 

Production area

Any sea, estuarine or lagoon area, containing either natural beds of bivalve molluscs or sites used for the cultivation of bivalve molluscs, and from which live bivalve molluscs are harvested for human consumption.

Relay area

Any sea, estuarine or lagoon area with boundaries clearly marked and indicated by buoys, posts or any other fixed means. A relay area is used exclusively for the natural purification of live bivalve molluscs to remove microbiological contamination on a all in all out batch basis.


Information on Shellfish Food Standards Scotland