25 Peraš et al. Water Research and Management, Vol. 8, No. 2 (2018) 25-31 Comparative Analysis of Bivalves Diversity on Experimental Spat Collectors Ines Peraš 1 , Slađana Gvozdenović 1 , Slavica Petović 1 and Milica Mandić 1 1 Institute of Marine Biology, Dobrota bb, 85330 Kotor, Montenegro; E-mail: mamilica@ac.me Abstract This paper presents the results of bivalves diversity on diferent types of experimental spat collectors. Samples were collected from two sites in the Boka Kotorska Bay, Orahovac and Kamenari, where the shellfsh farms are located. Two types of collectors were set up in June 2017 and processed after 6 months of immersion following which 9 families were determinated with a total of 15 diferent species of bivalves. Physical and chemical parameters at the depth where placed diferent types of collectors proved to be signifcant for the individual development and development of young shells. Keywords: diversity, bivalves, collectors, Boka Kotorska Bay. Introduction Boka Kotorska Bay is situated on the southeastern part of the Adriatic Sea and represents a specifc area with relief formed by the combined efects of tectonic processes and river erosions (Milojević, 1953). The bay is characterized by specifc hydrography and dynamics considering that it represents a semi enclosed basin (Lepetić, 1965). Boka Kotorska Bay is formed from four smaller bays, the Bay of Kotor, Tivat, Risan and Herceg Novi. The Bay of Kotor and Risan form the inner part of Boka Kotorska Bay creating the submerged bay cavity (Stjepčević & Žunić, 1964). The Strait of Verige (340m wide) connects the inner part of the bay with the outer part, Tivat and Herceg Novi Bay. Streaming of sea currents in Boka Kotorska Bay are almost irregular and depend on sea periods and free oscillations so called 'sesh' (Mandić et al., 2001). Winds, pressure changes and also the mixing of sea and freshwater have a big infuence on the direction and strength of the sea currents in Boka Kotorska Bay. Weaker sea currents are present in summer months while stronger currents are specifc for autumn, winter and spring months. During summer months, infow currents are stronger and have a northwestern direction. From October to May vertical streaming is present which is mainly expressed in the inner parts of Boka Kotorska Bay. It causes the mixing of water layers and the movement of nutritious salt deposits and detritus from the bottom, thereby signifcantly contributing to the increase in the amount of nutrients and productivity in general (ibid). The Bay of Kotor and Risan is characterized by strong turbulent currents, that are stronger during freshwater infow, as in the area of Morinj and Orahovac (Stjepčević & Parenzan, 1980). During the months when surface freshwater infow is small in the Kotor-Risan Bay, streaming has an outfow direction with the smallest speeds in the peripheral parts of the bay. The middle layer of the water column, at a depth of 5 to 10 m, sea currents still have an outfow direction but with lower intensity. Streaming of sea water in the Strait of Verige is about 0,66 knots (34 cm/sec). The dynamics of streaming become more intensive if there are higher infows of atmospheric and freshwater springs. Peripheral parts of the bay then have less intense streaming while circular currents periodically appear in the central parts due to the confguration of the basin. The velocity of the currents range from 0,1 to 0,5 knots (5 to 26 cm/sec). In the Strait of Verige, intense outfow currents reach velocities of 0,9 to 1,1 knots (46 to 56 cm/sec) (Mandić et al., 2001). Infows of freshwater in Boka Kotorska Bay vary. There are two rivers fowing into the Bay of Kotor - Škurda, which are active throughout the entire year and Ljuta which dries up during the summer months. In addition, there are a number of streams, small springs and submarine springs that also represent a signifcant source of fresh water. Situated near Kotor in the Kotor-Risan Bay) is an area with the highest amount of precipitation in Europe – Crkvice, from which by way of diferent springs, submarine springs and by erosion large amounts of freshwater infow into UDK: 504.5:[581.526.3:669.018.674