Algal bloom causes fish deaths in Norway
Extensive mortality of farmed fish has been recorded in the Boknafjord over the past 24 hours.
Norway's Institute of Marine Research writes that extensive mortality of farmed fish has been registered in the Boknafjord over the past 24 hours. The risk for the area has thus automatically changed to high risk of algal bloom with negative consequences. Algae samples will probably be taken from this area today.
"The samples taken yesterday (March 23) showed mostly high density in the outer parts and more variable density inside the fjord system," writes IMR.
Farmers in Production area (PO) 1 and outer parts of PO2 and PO3 should be aware of the ongoing presence and potential for local blooms of the alga Pseudochattonella.
Algae analyses for the area north of Haugesund, where there has been a report of an incident in connection with the algal bloom, show moderate to high concentrations of Pseudochattonella, which can affect behaviour and lead to somewhat increased mortality.
Modelled dispersion
A dispersion modelling has been carried out based on the incident north of Haugesund and algae analyses for the area.
Initially, the outer parts of PO3 from Haugesund to Selbjørnsfjorden may be at risk. The speed of spread will be greatly influenced by wind direction, wind strength and local current conditions.
"It is important to point out that there are currently only incident reports from the southern parts of PO3, and that more data is needed to be able to provide a more reliable assessment."
Based on the incident and potential spread, the risk for the Haugesund-Selbjørnsfjorden area is considered moderate. For the inner part of PO3, little information is available and the risk is considered low at this time.
Southern Norway: continued risk of fish being affected
For the areas south of Arendal, the risk is still considered high and may have a negative effect on fish. At the monitoring point outside Arendal (PO1), a marked reduction in the amount of Pseudochattonella was registered yesterday (March 23). The concentration registered may cause behavioral changes, but lower risk of increased mortality. Based on data for the last week, it appears that the bloom has passed Arendal.
