Izvorni znanstveni članak
INFLUENCE OF THE COOT (FULICA ATRA L. 1758.) POPULATION ON THE FISH DIET IN CARP PONDS
Antun Delić
; PMF, Sveučiliste u Zagrebu
Sažetak
Research on the influence of the coot (Fulica atra. F. 1758) population on the fish diet in carp ponds was carried out at the fish farm »Končanica« (Central Croatia) from 1985-1988. This influence can be characterized as
positive and negative. The positive influence is expressed by the fact that in the fish ponds it has the effect of a useful biological regulator: it prevents massive development of algae and higher water plants, which indirectly contributes to an increase in the amount of oxygen in water; by preventing shading of water surfaces caused by the development of phyto- and zooplankton as an important natural fish food; it consumes insects which are harmful to the fish farms' production; and finally, with its excretions it causes an increase of natural food in the fish pond. The negative influence is in the sense of competition for food with fish species in culture (consuming additional fish food for the whole time of supplement feeding the fish, consuming phytoplankton and water macrophyte as the main food of herbivorous fish species, then the molluscs and insects which are an important food of zoophage fish), also in the predatory sense, but in a very small amount, it consumes the fish young. Finally, the results obtained point to the fact that the coot is an important link in the biological chain of the fisheries ecosystems, therefore its' complete absence would definitely have certain harmful effects in fisheries production.
Ključne riječi
Hrčak ID:
75253
URI
Datum izdavanja:
1.3.1990.
Posjeta: 1.102 *