Monitoring Programme for Algal Toxins in Shellfish from Scotland
1 documents for this subject
Summary
Davidson, K., Miller, P.I., Wilding, T., Shutler, J., Bresnan, E., Kennington, K. & Swan, S. (2009)
A large and prolonged bloom of Karenia mikimotoi in Scottish waters in 2006.
Harmful Algae, 8, 349-61.
FRS Marine Laboratory
Howard, F
Marine biotoxins produced by certain species of phytoplankton can be accumulated in the tissues of filter feeding bivalve molluscs. If these molluscs are then consumed by humans, toxin related illness may occur. United Kingdom and European Community food safety regulations stipulate the levels of toxin permitted in products placed on the market for human consumption, and also require that monitoring for the presence of toxins be undertaken to ensure that no potentially hazardous shellfish are placed on the market for human consumption. A monitoring and surveillance programme is undertaken in Scotland, and samples of bivalve molluscs are tested for the presence of Amnesic Shelfish Poisons (ASP), Diarrhetic Shellfish Poisons (DSP), and Paralytic Shellfish Poisons (PSP). The maximum toxin levels permitted are ASP: 20 mg/g flesh, DSP; No toxins permitted, PSP: 80 mg/100 g flesh.
Fisheries Research Services (FRS) has conducted an extensive monitoring and surveillance programme for marine biotoxins in bivalve mollusc flesh in Scotland since 1991, and for the causative phytoplankton since 1995. The monitoring programmes are operated to comply with the requirements of the shellfish hygiene directive, 91/492/EEC, and with the current UK implementing legislation, The Food Safety (Fishery Products and Live Shellfish) (Hygiene) Regulations 1998, as amended.
The programmes are undertaken on behalf of the Food Standards Agency (Scotland) (FSAS).
The monitoring is carried out on bivalve mollusc samples from classified harvesting areas, and from offshore scallop fishing grounds; sampling is undertaken throughout the year. The programme is based upon a sampling frequency of monthly during the period October to March, and weekly, fortnightly or monthly during the period April to September. The sampling frequency is based on a risk assessment of each site, which takes account of the shellfish production and the historical occurrence of toxins. Sampling frequency is increased if toxins are detected, and species other than bivalve molluscs may be tested.
In the period 1 April 2001 to 31 March 2002, shellfish from 56 primary inshore production areas, 56 secondary areas and 10 offshore fishing areas were examined. A total of 6,300 mollusc samples were analysed; 2,029 for PSP, 1,145 for DSP and 3,126 for ASP.
In the inshore productions areas, PSP toxins were found in 80 samples from 32 sites, DSP toxins were found in 146 samples from 35 sites, and ASP toxins, above the Limit of Detection (LOD) were found in 96 samples from 18 sites. Voluntary Closure Agreements (VCAs) were made with affected aquaculture site operators, and warning notices erected where public access and harvesting could take place.
The site location and the result of samples with detected toxins above the permitted level, which resulted in harvesting restrictions being imposed, is shown below:
| Site | Date | No of samples | Species | Toxin PSP (mg STX equiv/100g) | DSP | ASP (mg DA/g) | Action taken |
|---|---|---|---|---|---|---|---|
| St Abbs |
May Aug-Sept |
1 3 |
Mussels Mussels |
142 | Positive | Warning notices erected | |
| Scapa Flow |
May-June June-Nov |
5 11 |
Mussels Mussels |
88 -245 | Positive | Restrictions imposed | |
| Kirkwall |
June Sept |
1 1 |
Mussels Mussels |
299 | Positive | Restrictions imposed | |
| Mill Sands | June | 1 | Cockles | 152 | Restrictions imposed | ||
| Whalefirth | Sept-Oct | 2 | Mussels | Positive | Closure order | ||
| Ura Firth | Sept | 1 | Scallop W | 20 | Closure order | ||
| Olna Firth |
June July/Oct |
1 2 |
Mussels Mussels |
184 |
Positive |
Closure order | |
| Busta Voe | June | 1 | Mussels | 163 | Closure order | ||
| Clift Sound | October | 1 | Mussels | Positive | Closure order | ||
| Clousta Voe | May | 1 | Mussels | 164 | Closure order | ||
| East Burra Firth | Jul-Oct | 5 | Mussels | Positive | Closure order imposed | ||
| Linga Voe |
May Jul/Oct |
1 2 |
Mussels Mussels |
211 | Positive | Closure order imposed | |
| Mid Yell Voe | May | 1 | Mussels | 130 | Closure order | ||
| Ronas Voe | May | 1 | Mussels | 86 | Closure order | ||
| Uyea Voe | Sept | 1 | Mussels | Positive | Closure order | ||
| Loch Eriboll | July-Oct | 4 | Mussels | Positive | Closure order | ||
| Loch Inchard |
May-June July-Oct |
2 11 |
Mussels Mussels |
112, 277 |
Positive | Closure order | |
| Loch Laxford | Aug - Oct | 8 | Mussels | Positive | Closure order | ||
| Kylesku | August | 1 | Mussels | Positive | Closure order | ||
| Loch Kirkaig | Sep/Mar | 2 | Mussels | Positive | Warning notices | ||
| Dornoch Firth | Sept-Oct | 3 | Mussels | Positive | Closure order | ||
| Little Loch Broom | Aug-Oct | 5 | Mussels | Positive | Closure order Imposed | ||
| Loch Broom | October | 1 | Mussels | Positice | Warning notice | ||
| Loch Ewe |
Jun-Aug Apr-Mar 02 |
7 23 26 |
Mussels Scallop G Scallop W |
Positive |
LOD – 43 10 - >100 |
Closure orders Imposed | |
| Loch Torridon |
May-June Jun/Sept |
4 6 |
Mussels Mussels |
80- 220 | Positive | Closure orders Imposed | |
| Loch Toscaig | Sept | 1 | Mussels | Positive | Restrictions imposed | ||
| Loch Kishorn | Aug-Oct | 4 | Mussels | Positive | Closure order | ||
| Broadford Bay |
Aug-Dec Jun-Sept May Aug-Sep |
4 5 1 3 |
Mussels Queens Scallop G Scallop W |
Positive Positive |
27 43 - 67 |
Closure ordersImposed | |
| Loch Ainort | October | 1 | Scallop W | >100 | Restrictions imposed | ||
| Loch Sligachan |
May-Dec Aug/Feb |
8 2 |
Scallop G Scallop W |
LOD- 64 29, >100 |
Closure orders imposed | ||
| Loch Greshornish |
Jun-Jul Jul-Oct |
2 5 |
Mussels Mussels |
148,122 |
Positive |
Closure ordersImposed | |
| Loch Dunvegan |
June Oct-Nov |
1 2 |
Mussels Mussels |
405 |
Positive |
Closure ordersImposed | |
| Loch Harport | Jul/Oct | 2 | Mussels | Positive | Closure order | ||
| Loch Eishort | July | 1 | Mussels | 89 | Closure order | ||
|
Badicaul |
Sep-Oct July May/Aug/Dec/Feb June/Feb |
2 1 4 2 |
Queens Scallop W Scallop G Scallop W |
Positive Positive |
27,26,38,2326,70 | Closure order and restrictions imposed | |
| Loch Hourn | Jun-JulAug-Nov | 310 | Mussels | 214 121, 98 | Positive | Closure orders imposed | |
| Loch Leven | May | 1 | Mussels | Positive | Closure order | ||
| Loch Roag |
Jun-Jul October Sept |
2 1 1 |
Mussels Mussels Mussels |
101, 127 |
Positive |
22 |
Closure orders imposed |
| Loch Creran | October | 1 | P.oyster | Positive | Closure order | ||
| Loch Crinan | Jun-Feb | 6 | Scallop W | 56 - >100 | Closure order | ||
| Loch Coalisport | Sept | 2 | Scallop W | >100 | Closure order | ||
| Barmore | Aug/Oct-Nov | 3 | Queens | Positive | Closure orders imposed | ||
| Ardkinglass | Aug -Nov | 5 | Mussels | Positive | Closure order | ||
| Loch Striven | Aug/Oct-Nov | 3 | Mussels | Positive | Closure order | ||
| Loch Scridain | Jul/Sep | 3 | Mussels | Positive | Closure order | ||
| Fairlie |
Aug-Oct December October |
8 1 |
Mussels P.oyster |
Positive Positive |
Closure orders imposed |
In the offshore scallop fishing areas, PSP toxins were found in both scallop gonad and whole scallop samples in the East Coast, Moray Firth, Orkney, Shetland, Hebrides, and the North and South Minches. PSP toxins were found only in whole scallops in the Sound of Jura, and none were found in the Clyde or Irish Sea. DSP toxins were found, using the bioassay, in whole scallops in all areas except Shetland, while ASP toxins were found in both gonad tissue and whole animals in all areas. In Shetland, Clyde and Irish Sea areas, detected ASP levels in gonad tissue were below the action level.
For the offshore scallop fishing areas, PSP toxins at or above the action level were found in 18 (3%) gonad tissue samples, and 55 (10%) whole animals. DSP was found in 81 whole animal samples (47%) by bioassay. ASP toxins at or above the action level were found in 111 (10%) gonad tissue samples, and in 786 (71%) whole animal samples.
Fishing restrictions by means of a closure order under the Food and Environment Protection Act 1985 (FEPA) or shucking requirements (whereby only the processed adductor muscle and gonad are permitted to enter the marketplace) were imposed where appropriate.
Project Code: S02007
