Zooplankton in Montenegrin Adriatic Offshore Waters

This chapter includes a review of the recent results regarding zooplankton in offshore Montenegrin waters (since 2009) and a comparison of these results with earlier surveys. The highest abundance of total zooplankton was determined at station E, close to the river Bojana, in the summer period reaching 74,972 ind m−3. A lower density of total zooplankton was observed during the winter. The abundance of total zooplankton increased toward the southern part of Montenegrin waters and from offshore to coastal stations. Contrary to the abundance, biodiversity grew from the coastal to the offshore sites as well as from the southern to the northern part of Montenegrin waters. Thirteen groups and 126 mesozooplankton taxa were determined. Analysis of the 12-month monitoring revealed that copepods were the most dominant group with an average contribution of 79% and a maximum share of 99%. Copepods were the most diverse group with 44 determined taxa. The most dominant taxa were Onceaidae-like species with 17% share, followed by: Oithona nana (14%), Acartia (Acartiura) clausi and Euterpina acutifrons (10%), and Paracalanus parvus parvus (8.5%). Cladoceran species dominated during the summer period, but the average contribution was 10%. Noctiluca scintillans reached a maximum value of 6,417 ind m−3 in August 2009 at A3 station. Seventeen taxa of hydromedusae and 11 species of siphonophorae were collected during the survey period. Chelophyes appendiculata was noted for the first time in Montenegrin waters. High abundances of meroplankton larvae were recorded in this area throughout the investigation period, representing 2.7% of the total mesozooplankton. Bivalve larvae generally constituted the majority of this population.