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THE QUALITY OF WATER AND ICHTHIOFAUNA OF THE SOUTHERN LAKE IN OSIJEK – THE CONDITIONS FOR BIOMANIPULATION
M. Mihaljević
A. Opačak
I. Bogut
D. Novoselić
Sažetak
The Southern lake is shallow (deep up to 4 meters) artificial lake with the ackerage of 6. 25. It is situated within the city of Osijek. Its reconstruction began in 1995, after it has been polluted for many years. The results of, hydrobiological examination show the basic ecological characteristics of the Southern lake: high transparency, great quantity of nutrients and highly developed macrophit vegetation. After the conducted analysis of the qualitative composition of the ichthiofauna, it has been found that the lake has 13 species of fish form six families, with the greatest number of them coming from Cyprinidae family. idae family. The fish species that outnumbers all other in the quantitative composition of the ichtiofauna is P. parua, but also well represented are L. gibosus, C. carrasius gibelio, Scardinius erythrophthalmus and Rutilus rutilus. In the trophic structure, the ratio of the predatory species is disadvantageous in relation to the unpredatory species. The application of the biomanipulation method has been suggested for the further reconstruction of the Southern lake: the quantity of the macrophit vegetation should be reduced by the way of its direct removal and the input of the herbivore fish species. The disadvantageous trophic ratio should be changed by overfishing of predatory species within the ichthiofauna and the input of unpredatory fish species.
Ključne riječi
Ichthiofauna; quality of water; biomanipulation; eutrophic lake
Hrčak ID:
48115
URI
Datum izdavanja:
30.6.1996.
Posjeta: 1.457 *