Norway’s Institute of Marine Research (HI) has raised the risk assessment for production area 3 (PO3) after receiving an incident report from north of Haugesund linked to the ongoing Pseudochattonella algae bloom.
In a status update dated 22 March, HI said algae samples taken slightly south of the reported incident showed moderate concentrations capable of causing behavioural changes and some increased mortality in farmed fish.
Dispersion modelling carried out after the incident suggests the outer parts of PO3 from Haugesund to Selbjørnsfjorden could be at risk over the next five days. HI said the assessment for PO3 has now been set at moderate, though additional data will be needed to confirm the scale of the bloom.
High concentrations of Pseudochattonella have also been recorded outside Arendal in production area 1 (PO1), where levels are considered sufficient to cause behavioural changes and increased mortality in farmed fish.
Monitoring data also shows increasing algae presence in the outer parts of production area 2 (PO2), with the risk level in those areas now assessed as moderate.
HI has asked farmers in PO1 and the outer parts of PO2 and PO3 to report any behavioural changes or increased mortality linked to the bloom.