Oysters in Chichester Harbour
Oysters have been harvested in Chichester Harbour for centuries, peaking in the 1900's. Currently the oysters in the harbour offer a high quality, high value product. Since 1993, Chichester and Havant Councils have operated a programme for monitoring, classifying and reviewing the shellfish harvesting areas in Chichester Harbour for public health reasons. As part of this programme, we also monitor for biotoxins which arise from naturally occurring algae in the sea. If contaminated shellfish are eaten, then this may make people ill.
Sampling result information
From the sampling results, each bed is classified. For the map showing the areas of classification for Oysters please see Food agency shellfish classification webpage. To manage any food safety issues arising from the sampling of the oysters in Chichester Harbour, the councils have an 'Action Plan'; this identifies the action to be taken, under what circumstances, and who to contact. Anyone can be part of the Action Plan, and people who have an interest in the Harbour were invited to join. If you would like to be included in the Action Plan please contact Health Protection and your details will be added.
It is illegal to collect shellfish to sell without having registration forms. In some areas small quantities of shellfish can be gathered for your own use but they must be cooked well to be safe. If you commercially harvest shellfish these must be taken from classified harvesting areas and each batch accompanied by a shellfish registration document. If you collect whelks these must also have a registration document that goes to the processor or dispatch centre showing where the whelks came from.
Bivalve mollusc (shellfish) harvesting areas are classified according to the extent of contamination shown by monitoring of E.coli in shellfish flesh. Treatment processes are stipulated according to the classification status of the area. The classification categories are:
(≤ 230 E.coli/100g) - molluscs can be harvested for direct human consumption
(90% of samples must be ≤ 4600 E.coli/100g; all samples must be less than 46000 E.coli/100g.) - molluscs can be sold for human consumption:
- after purification in an approved plant, or
- after re-laying in an approved Class A re-laying area, or
- after an EC-approved heat treatment process.
(≤ 46000 E.coli/100g) - molluscs can be sold for human consumption only after re-laying for at least two months in an approved re-laying area followed, where necessary, by treatment in a purification centre, or after an EC-approved heat treatment process.
In all cases, the health standards in Annex III of EC Regulations 853/2004 and the microbiological criteria adopted under EC Regulation 2073/2005 must be met. Molluscs must not be subject to production or collected in prohibited areas.
There are two classification systems in England and Wales:
- the annual or "temporary" classification system
- the long-term classification (LTC) system
Algal toxins surveillance
At certain times of the year naturally occurring algae in the sea can give rise to blooms, which may not necessarily be noticeable. Algae in these blooms may produce potent bio-toxins. These can accumulate in filter-feeding bivalve molluscs and sometimes in other shellfish, such as grazing gastropods.
There are currently three major shellfish bio-toxin groups that can be detected in shellfish, which are subject to statutory testing to protect human health. These are:
- Paralytic shellfish poisoning (PSP) toxins
- Lipophilic toxins, including those responsible for diarrhetic shellfish poisoning (DSP)
- Amnesic shellfish poisoning (ASP) toxins
EC Regulation 854/2004 prescribes the legal controls that are placed on the production and marketing of live bivalve shellfish to ensure that contaminated shellfish are not placed on the market.