Geographical variation inFucus vesiculosusmorphology in the Baltic and North Seas

Abstract

Effects of stress and disturbance on morphology, reproductive effort, size and sex ratio were studied for Fucus vesiculosus populations from the Baltic Sea at Asko and the North Sea on the west coast of Sweden at Tjam[otilde]. High morphological variation was found between Fucus populations, with significant differences in length and weight of individuals, thallus breadth, number of branches and receptacles and receptacle weight, not only between Baltic and North Sea populations but also between populations within the same area, differing in wave exposure. With increasing disturbance, individuals in both studied populations were smaller and less branched. Differences were observed in plant size, with longer, broader and more branched plants being found in Asko compared with Tjarno. Fucus populations at Tjamo allocated more biomass to reproduction and had longer, heavier receptacles than at Asko. Although the observed morphological changes may be partly explained by differences in wave exposure and salinit...