3 sites in the Gdansk Basin: station 92A (54° 26'N, 18° 40'E), station R6 (54° 57.5'N, 18° 24'E), station G2 (54° 50'N, 19° 20'E). Station 92A was an inshore sheltered site; station R6 was located inshore; and station G2 was an offshore site close to the open sea

Zooplankton wet weight biomass; Zooplankton taxonomy-related abundance per unit volume of the water column

The main goal of this project was to obtain a full and complex picture of the whole biocenosis and physical environment in the researched area. The exact sampling dates are as follows: 20-21 Jan, 11-14 Feb, 27 Feb-01 Mar, 23-25 Mar, 30 Mar-02 Apr, 13-15 Apr, 27-30 Apr, 11-13 May, 26-28 May, 15 Jun, 29 Jun-02 Jul, 14-17 Jul, 05-08 Aug, 23-27 Aug, 08-11 Sep, 22-25 Sep, 14- 16 Oct, 26-29 Oct, 16-18 Nov, 03-05 Dec, 15-18 Dec 1987 and 12-15 Jan 1988. The mesozooplankton abundance was measured based on the vertical hauls with a WP-2 net of 100 microm mesh size at the following depth strata: 0-15m and 15m- bottom (stations 92A and R6); 0-15, 15-30, 30-60, 60-90 and 90m-bottom (station G2). In addition, water samples were drawn with a bathymeter from the following depth strata: 0-30m, every 5m; 30m-bottom, every 10m. Water samples were strained through a 60 microm mesh and pooled according to the following depth layers: 0-15, 15-30, 30-60, 60-90 and 90m-bottom. All zooplankton samples were preserved in a 4% formaldehyde-sea water solution buffered with borax, and identified under a binocular microscope. A Folsom splitter was used to obtain subsamples of the material. Not less than 500 individuals per sample were measured and their body volumes were estimated by approximating the actual body shape with a simplified geometric form. Taxonomic classification of organisms in samples was performed to the highest possible taxon level (usually, to the species level). Also, the developmental stages of copepodites were identified. Fish eggs, copepod eggs and larval stages of benthic organisms were enumerated.

National Marine Fisheries Research Institute
Kollataja 1
Gdynia

81-332
Poland