Harmful Algal Information System: Event GB-94-005

General Information

Event name:	GB-94-005
Country:	UNITED KINGDOM
Nature of the harmful event:	Seafood toxins
Event directly affected:
Toxicity detected:	Yes (Approximate range: 5,040 mu.)
Associated syndrome:	PSP
Unexplained toxicity:	No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme:	Yes (SOAFD Monitoring Programme.)
Event occurred before in this location:	Yes (Regular occurrence since 1990.)
Individuals to contact:	MACDONALD, Elspeth , HOWARD, Godfrey

Location & Date

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Location:	Latitude: , Longitude:
General location information:	, Orkney Islands. HAB Area code(s): GB-20
Additional location information:
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information:	Early May - September. Six closure orders were enforced beginning on 21st May and finally lifted on 17th September.

Microalgae

Causative organism known:	Yes
Causative Species/Genus:	Alexandrium sp. (< 1,000 cells/L) Alexandrium cf. Tamarense. Waulkmill Bay
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known:	µg/l
Additional bloom information:
Event-related bibliography:

Environmental Conditions

Weather:	Summer weather was generally cool and wet.	Turbidity (NTU):	Wind direction:
Stratified water:	No	Oxygen content (nL/L):	Wind velocity:
Temperature (°C):		Oxygen saturation %:	Current Direction:
Sechhi disk (m):		Salinity:	Current Velocity:	0

Nutrient information:

Temperature Range During Event:

Max: °C, Min: °C

Salinity Range During Event:

Bloom location in the water column:

Growth:

In situ

Growth Comments

There is a small population of Alexandrium cysts in parts of Scapa Flow, so in some cases, toxicity could be caused by in-situ populations.

Additional Environmental information:

No detailed information.

Toxin Assay Information

Species containing the toxin	Toxin type	Toxin details	Max. concentration	Assay type
Mytilus edulis	Saxitoxins	STX eq	658 ug/100g	Bioassay-Mouse

Kit used:

Type of kit used:

Additional information:

PSP toxins detected in pectinids, mussels and razor fish from many sites in the area. Maximum toxicity (5,040 mu/658 ug/100g) was recorded in early June and although levels then declined, they did not drop below 400 mu until early September.

Economic losses:

Management decision:

Six closure orders were enforced beginning on 21st May and finally lifted on 17th September.

Additional harmful effect information:

PSP toxins were also detected in brown crab and lobsters but were found to be mainly < 400 mu. Velvel crabs had toxin levels up to 1924 mu. No action necessary, as fisherman imposed a voluntary closed season.

Updated at 09:59 on 9 Oct 2020