Changes in the morphology of Fucus vesiculosus L. and abundance of seaweed associated fauna along the coastal sea of Estonia

The aim of this study is to give an overview of the morphological differences of Fucus vesiculosus in relation to environmental factors - salinity and bottom shear stress. In addition to that we also analysed diversity and abundance of F. vesiculosus associated fauna. Samples of F. vesiculosus were collected in 2013 by SCUBA diving from four study sites in Estonian coastal waters along the salinity gradient in the North-Eastern Baltic Sea. Our findings make a contribution to the field of sea ecology in Estonia as well as in the Baltic Sea on the whole. Our study confirms some results from previous articles - salinity is an important factor that affects F. vesiculosus morphology. However, we also obtained some new material about coastal F. vesiculosus individuals getting taller with decreasing salinity. Weak effect of wave action (bottom shear stress) on F. vesiculosus morphology is another unexpected result. Abundance and diversity of F. vesiculosus associated fauna also varies between study sites and is affected by salinity and wave action.