Diversity of Appendicularia in Boka Kotorska Bay (Southern Adriatic Sea; NE Mediterranean)

Abstract

Appendicularia were collected monthly at seven stations with different hydrographic characteristics at Boka Kotorska Bay in Southern Adriatic, during 2008. We present the Boka Kotorska Bay hydrographic data, together with the data on presence, abundance and distribution of the eight species from two genera.

Former studies have shown that Boka Kotorska Bay is a specific biotope within the southeastern part of Adriatic. Living conditions at Boka Kotorska Bay are very different than those at the open sea. It features typical characteristics of closed coastal waters of the East Adriatic. Zooplankton is represented mainly by eurythermal and euryhaline species, as well as open-sea species that enter the Bay from the deep waters of the southern Adriatic and die out shortly. The Appendicularia of Boka Kotorska Bay are not well-known. Our research has shown that two genera of Appendicularia fauna were present in Boka Kotorska Bay: Oikopleuraand Fritillaria. The Oikopleuragenus was represented by species: O. dioica, O. longicauda and O. fusiformis, while the Fritillariagenus was represented by species: F. aequatorialis, F. megachille, F. pellucida, F. haplostoma and F. borealis. Four species (O. fusiformis,F. aequatorialis, F. megachille and F. borealis) were recorded in Boka Kotorska Bay for the first time. Our observations are based on the analysis of zooplankton samples collected monthly at three shallow stations near the seafood farming areas and four stations in the centre of each inner bay within Boka Kotorska Bay (Kotor, Risan, Tivat and Hercegnovi bays). Zooplankton was collected using Nansen net (100 and 150 μm). The following physical quantities were measured at the same time: temperature [ °C], salinity [‰], pH factor, dissolved O2 concentration [mg/l], Secchi disk depth [m] and colour of the sea using Forel scale I–XXI.