Methods Benthic communities classification in the Inner Puck Bay Urszula Janas, Halina Rzemykowska, Institute of Oceanography, University of Gdańsk

Information on vegetation – present/absent Vegetation cover Dominant species

% vegetation cover Visually by scuba divers observations – Circle (20 m diameter) at studied stations -50 stations (Maritime Institute) -31 stations (University of Gdańsk) Video camera records during cruises -15 stations (Sea Fisheries Institute, University of Gdańsk) Additionally by image analyses (6 pictures per stations or films).

% vegetation cover was estimated using 12-grade scale

Taxa composition and dominant species - macroflora Samples taken by divers – 52 stations DAK sampler (Maritime Institute) Dominant species one or several species > 50 % of total biomass Films (21 stations, Sea Fisheries Institute) and pictures (18 stations, University of Gdańsk) Dominance determined by visual volume (BalMar 2005) Visual volume >50 % of total visual volume

Visual volume – index obtained by multiplaying the percentage coverage by average height of the species (BalMar 2005).

For pictures following groups were used: Zostera marina Other vascular plants: Potamogeton spp. / Zannichellia palustris / Ruppia maritima Chara spp. Soft bottom –Covered by filamentous algae –Animals or their activity –Sand

Taxa composition and dominant species macrofauna Grabs samples collected at 54 stations. Dominant species or group of species Species with biomass >50 % of total biomass

Dominant species names the biotope. The biotope name may include several species names, when no single species forms required 50 % of visual volume/biomass. In such a case, the next most abundant species are added untill they all together make up 50 % (BalMar 2005).

Sampling stations Knowledge Publications Aerial photographs and satelite images