Annual cycle of the fish killing Chrysochromulina leadbeateri in Oslofjorden

Chrysochromulina leadbeateri has caused recurrent blooms in Northern Norway since 1991. The most recent bloom was in the spring of 2019, when approximately 13 000 tons of farmed salmon, at an estimated value of 800 million NOK was killed. The species is also present in Oslofjorden, but little is known about its occurrence. Chrysochromulina leadbeateri is a small haptophyte (ca 5 µm) that cannot be identified with certainty in light microscopy. Electron microscopy of the scales covering the cell or molecular identification such as qPCR (quantitative polymerase chain reaction) is required for exact identification and enumeration. A qPCR assay has already been developed and will be tested in this master project. Assay results will be confirmed with electron microscopy.

Bildet kan inneholde: organisme, vann.

Scanning electron micrograph of Chrysochromulina leadbeateri showing the two flagella, the haptonema and the scales covering the cell body.

Field work/cruise:

Onboard R/V Trygve Braarud once every month during one year.

Collect water samples and net hauls.

Measure salinity, temperature, fluorescence and water transparency.


Laboratory work:

Quantify and identify Chrysochromulina leadbeateri with qPCR.

Confirm identification of C. leadbeateri with electron microscopy.


Research questions:

At what time of the year is C. leadbeateri present in Oslofjorden?

How abundant is C. leadbeateri?




Publisert 13. aug. 2020 11:32 - Sist endret 19. okt. 2020 16:46

Omfang (studiepoeng)