Shellfish Monitoring

In order to help protect consumers’ health and meet EU legislative requirements, Ireland has a Shellfish Harvesting Monitoring Programme in place, to ensure shellfish containing biotoxins are not harvested and placed on the market. Biotoxins are naturally produced by phytoplankton in seawater. As shellfish are filter feeders, they can accumulate biotoxins in their flesh – which could cause illness if eaten.

How does the monitoring programme work?

The programme is supervised by the Sea-Fisheries Protection Authority and the Marine Institute, under service contract to the FSAI. Samples of farmed and wild shellfish are collected from commercial shellfish production areas, around the coast of Ireland, and tested for the presence of four biotoxin groups:

  • amnesic shellfish poisoning (ASP)
  • azaspiracid poisoning (AZP)
  • diarrhetic shellfish poisoning (DSP)
  • paralytic shellfish poisoning (PSP)

The main species of shellfish tested are:

  • clams
  • mussels (both cultured and wild caught)
  • native and pacific oysters
  • razor clams
  • scallops

The results of the most recent tests are used to give each shellfish harvesting area a biotoxin status of: 

  • Open – areas with two clear samples, taken 48 hours apart
  • Closed – areas with a biotoxin positive sample
  • Closed pending – areas with one clear sample but awaiting the result of the second sample taken 48 hours later

Only shellfish from open areas are allowed to be harvested and placed on the market.

Samples of seawater are also routinely taken to check for the presence of phytoplankton species that are associated with the production of biotoxins.

Further details on the monitoring programme are available in the Code of Practice for the Irish Shellfish Monitoring Programme (Biotoxins).

Where can I find the testing results?

Results of testing carried out under the Shellfish Harvesting Monitoring Programme are available from the Marine Institute.

See shellfish monitoring results from the Marine Institute’s website.

What other monitoring takes place?

Shellfish production areas are defined and classified using microbiological data by the Sea Fisheries Protection Authority (SFPA). Areas are classified following a full assessment of the microbiological risk and the classification given to an area determines whether shellfish harvested in that area require post-processing treatment and, where appropriate, the level of such treatment. The results from this monitoring are not used to open and close production areas on a week-to-week basis. Ongoing monitoring establishes if the level of risk has changed and if any follow-up action is required. 

Any questions or comments? Email us at or call our Advice Line on 1890 33 66 77.



Last reviewed: 5/4/2019