General Information

Event name: GB-94-003
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 4,707 units/658 ug/100g)
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: No
Event occurred before in this location: Yes (Regular occurrence since 1990.)
Individuals to contact: HOWARD, Godfrey , MACDONALD, Elspeth

Location & Date

[View larger map]
Location: Latitude: , Longitude:
General location information: Orkney and Shetland.,
HAB Area code(s): GB-20
Additional location information: As in 1992 and 1993, Orkney was badly affected by PSP toxins which were detected in a range of different bivalve species. Mussels, scallops and queens were the worst affected, but toxins were also found in razor fish and oysters. All areas of Orkney Islands were affected and PSP toxins were also found in the Shetlands.
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Toxins detected between: Mussels (Mytilis edulis): Mid-Apri, - End August Scallops (Pecten maximus): End June - Early August Low levels of toxins detected between: Brown crab (Cancer pagurus): End July - Early August (peak 267 units) Lobster (Homarus gammarus): End July (peak 350 units) Razor fish (Ensis spp.): End July (peak 377 units) Oysters (Crassostrea gigas): Early July - End July (peak 365 units)


Causative organism known: Yes
Causative Species/Genus: Alexandrium spp. ( cells/L)
low levels in May
Dinophysis spp. (500 cells/L)
Late April
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: A new phytoplankton monitoring programme is being set up next year.
Event-related bibliography:

Environmental Conditions

Weather: 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 Comments Not known.
Additional Environmental information: No information available.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Mussels Saxitoxins 658 ug/100g Bioassay-Mouse
Kit used: Type of kit used:
Additional information:
Economic losses:
Management decision: Initially voluntary closure agreements were sought with shellfish farmers, but as the outbreak became more widespread and deeper water scallop ground were affected, closure order made under FEPA 1985 were introduced. The first order was made on the 20th o
Additional harmful effect information: Toxins in mussels first appeared at the begginning of June and by the end of the month levels had reached 1806 units, peaking at 4707 units in mid-July. Toxins in scallops peaked at 3692 units in mid-July and continued to be detected until the end of Aug
Updated at 09:46 on 9 Oct 2020