Short-term study on the early succession stages of fouling communities in the coastal zone of Puck Bay (southern Baltic Sea)

The aim of this study was to distinguish the early succession stages of the fouling community in Puck Bay at depths of 3-7 m, to evaluate its biodiversity and to find the point at which the biodiversity of the assemblages achieved similarity. The depth at the study site was 8 m. The investigation lasted from 24 July to 22 September 2008 (61 days) when the colonisation and succession process of fouling communities is most intensive. During this period five sets of samples were collected. The investigations were focused on sessile organisms that established themselves on 105 PVC settlement panels (15 x 15 cm, 0.2 cm thick), 21 panels being deployed at each of five depths - 3, 4, 5, 6 and 7 m. A total of twelve sessile taxa and eight mobile (accompanying) taxa were identified over the course of the experiment. The panels became overgrown with fouling organisms in a characteristic manner - a layer of barnacles became covered with a layer of mussels. This type of community development created a double-layered structure (multi-strata growth). Assemblages reached a thickness of 2 cm as a result of the stratified fouling process. The species diversity was highest on 12 August (the first sampling day) at 7 m depth. Biodiversity differences during the study indicated that communities from all examined depths in Puck Bay became similar after a two-month colonisation period. By the end of the study Balanus improvisus and Mytilus trossulus were dominant in the communities at all depths.