Valerica Gîlcă

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RESEARCH ON THE TROPHIC ROLE OF AQUATIC PLANTS ON THE FISH FROM FISH PONDS

Valerica Gîlcă, I. Gîlcă, B. Păsărin, Doina Leonte

Abstract
Research has been aimed at identifying the role of aquatic organisms feed on freshwater fish species, summer II, under non-fodder, based on existing natural food ponds. Experiments were conducted at the farm Dracşani-Botosani, from June 15 to August 16, 2009. During the conduct of research data were recorded on planktonic biomass values and its role on the evolution of fish from fish ponds investigated. Were used for this purpose four ponds with identical surfaces and volumes of water (2500 square meters area and 4000 cubic meters of water volume per pond). Natural food was represented by phytoplankton (Chlorophylls, cianofite, euglenofite, bacilariofite, crisofite), zooplankton (cladocere, copepode, rotifere), Bent (molluscs, annelids, polichete, oligochete, crustaceans, aquatic macrophytes, larvae of insects). All three formulas, content from fish: C. carpio, H. molitrix, A. nobilis, Ictiobus cyprinellus, Ct. idella, Silurus glanis) which are non or partially food competitors in the best position to capitalize on natural food resources. Regarding densities, we used a minimum density, a maximum and two identical and best formulas. Fishery production undertaken by the experimental formulas varied between 359.3 and 634.2 kilograms / hectare without administration of conventional feed. The analysis of data concerning of production by the species was observed that densities is inversely proportional to individual growth, but without influence on the production gain realized.

Key words: fish, plants, food, pools, production