Volume 9
Issue 2
Fisheries
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume9/issue2/abs-16.html
EFFECTS OF ENVIRONMENTAL FACTORS ON THE OCCURRENCE OF THE HARPACTICOIDA IN THE ZOOPLANKTON AND IN THE DIET OF THE SMELT OSMERUS EPERLANUS (L.) IN THE VISTULA LAGOON
Anna Go寮ziejewska1, Ewa Paturej1, Alina Krajewska-So速ys2
1 Department of Applied Ecology,
University of Warmia and Mazury in Olsztyn, Poland
2 Department of Fisheries Oceanography and Marine Ecology,
Sea Fisheries Institute in Gdynia, Poland
ABSTRACT
The composition of food consumed by larval and juvenile smelt (Osmerus eparlanus) in the Vistula Lagoon was analyzed taking into account changing environmental conditions. The fish and zooplankton were collected at two stages of research, at the end of May and at the beginning of June 2000. The meteorological conditions and physicochemical parameters of water were determined within a limited research area, where a dense network of 15 sampling sites was established. The digestive tracts of 2552 smelts with a standard body length (SL) of 10 to 34 mm were subjected to preparation. A qualitative and quantitative analysis of diet composition was performed within 5-mm fish body length classes, taking into consideration time- and space-variation, as well as changing environmental conditions, primarily wind strength and the depth of sampling sites. Particular attention was paid to the occurrence of a non-specific component in the diet of the pelagic smelt – copepods of the order Harpacticoida, found in bottom deposits. These organisms were present both in the zooplankton and in the food of smelt, and the intensity of their occurrence varied in time and space. The analysis revealed that the presence of the Harpacticoida in deep waters and in the diet of smelt was directly proportional to wind strength and inversely proportional to the depth of sampling sites.
Key words: depth, Harpacticoida, smelt (Osmerus eperlanus), turbulences, wind velocity.
Anna Go寮ziejewska
Department of Applied Ecology,
University of Warmia and Mazury in Olsztyn, Poland
M. Oczapowskiego 5, 10-957 Olsztyn, Poland
email: gozdzik@uwm.edu.pl
Ewa Paturej
Department of Applied Ecology,
University of Warmia and Mazury in Olsztyn, Poland
M. Oczapowskiego 5, 10-957 Olsztyn, Poland
email: epaturej@uwm.edu.pl
Alina Krajewska-So速ys
Department of Fisheries Oceanography and Marine Ecology,
Sea Fisheries Institute in Gdynia, Poland
Ko陶ataja 1, 81-332 Gdynia, Poland
email: akraj@mir.gdynia.pl
Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.