In the Skagerrak and Kattegat the plankton flora is rich and dominated of "early summer diatoms". Ceratians are common in the Skagerrak and in the Kattegat there is a bloom of cf. Heterosigma sp. In the southeast part of the Baltic there are still remains of the spring bloom. In the other areas it is a post spring bloom situation with lots of flagellates. In the Bornholm Basin there was a bloom of Chaetoceros similes.