TABULARIA-WAERNII (DIATOMOPHYCEAE) IN THE NORTHERN BALTIC SEA

Tabularia waernii Snoeijs is a common epiphyte in the Baltic Sea. We h ave studied its distribution in 313 samples of epiphytic diatoms colle cted along the SW coast of Finland. T. waernii is abundant in the uppe r sublittoral of the outer archipelago zone and the sea zone. In the m ost exposed localities it was present throughout the year, with maximu m abundance in June-July. T. waernii was an epiphyte on all filamentou s macroalgae examined, however, it clearly preferred Pilayella littora lis as a host alga. It appears to be a slow colonizer, since it was ra rely found on the young thalli of any host.