Alenka Malej, National Institute of Biology, Marine Biology Station Piran, Piran, Slovenia, Davor Lucic, University of Dubrovnik, Institute of Marine and Coastal Research, Dubrovnik, Croatia, Matjaz Licer, National Institute of Biology, Piran, Slovenia, Tjasa Kogovsek, National Institute of Biology, Marine Biology Station, Piran, Slovenia and Petra Lucic, Institute of Oceanography and Fisheries, Split, Croatia