Baltic Proper, Bornholm Basin, Gotland Basin, during the period 1991-1992 (data set limits: 54 53 - 59 23N; 13 23 - 22 11E); Baltic Proper, Gdansk Basin, Gotland Basin during the period 1993-1999 (data set limits: 54 54 - 57 22N; 18 24 - 21 05E); Lithuanian territorial and exclusive economic zone since 2000 (data set limits: 55 19 - 56 02N; 19 14 - 21 05E)

Zooplankton taxonomy-related abundance per unit volume of the water column; Zooplankton non taxonomy-related abundance per unit volume of the water column

Plankton nets; optical microscopes

The zooplankton is an important indicator in the assessment of environmental state, pollution level. It is an important link between the phytoplankton and higher trophic level such as fish. The purpose of the research - to describe the community structure and the spatial distribution in species composition, abundance within the research area as well as to evaluate seasonal and long term variability in the zooplankton. According to HELCOM requirements the investigations started in 1991. During the first year of research sampling was carried out in international (HELCOM) monitoring stations. Since 1992 the researches were carried out not only in open Sea but and in the coastal waters of Lithuania. Later the net of stations became narrower and since 2000 research in the Baltic Sea has been carried out only in the territorial and exclusive economic zone of Lithuania. In accordance with the national and international Baltic Sea monitoring (HELCOM) programme, sampling of zooplankton is carried twice a year (spring and summer) except the period from 1993 to 1994 when sampling was performed once a year (summer). Research of zooplankton was performed according to HELCOM methods. During the sampling WP-2 net from the research vessel 'VEJAS' was used. Samples were taken from different water layers (bottom-halocline, halocline-thermocline, thermocline-surface) depending on water stratification. The data are fully quality controlled. Systematic certification of laboratories, participation in international intercalibrations, internal control, introduced managing system for research' quality determine quality of data. All data is stored in archive (written form) and is saved on hard disk.

N. Budajeva (1998) Distribution of mesozooplankton in the Klaipeda strait of the Kurshiu Marios Lagoon and the Baltic coastal zone / The environmental status of the Baltic Sea and Kurshiu Marios Lagoon (Articles in Lithuanian with English summaries), Virginija Cizauskiene; N.Demereckiene (2008) Research of zooplankton in the area of dumped chemical munition / Monograph: The Baltic Sea and its problems (Articles in Lithuanian with English summaries), N.Remeikaite, R.Nikzentaitiene

Department of Marine Research of the Environmental Protection Agency
Taikos Av. 26
Klaipeda

LT-91149
Lithuania