Marisia - Maros Megyei Múzeum Évkönyve 29-30/2. (2010)
Zoology
Gabriela GRIGORAS heavier fish are in better condition than lighter of the same length [8, 15]. Any stressors in the natural environment can have an effect on fish overall health and condition. Therefore, this factor can be employed as an interactive biomarker; both anthropogenic and natural stressors are incorporated into Fulton Factor. Flowever, there are natural fluctuations or differences in condition factor of fish to species, sex and season (e.g. temperature, spawning, photoperiod, prey quantity/quality) [4, 8, 15], so, special attention must be given to these variables when developing the research strategies. The condition status evaluated by the weight/length ratio depends on the fish body shape: the bigger body height and thickness are related with an increased Fulton factor than the fish with thin and long body. This index provides important information in connection with physiological status of fish having in view the specimens with the same body length have a better condition as a greater body weight is. Additionally, the comparative researches of distinguishes populations allow the living environment quality assessment [9]. Materials and methods The research period. The experiments were performed in varied winter conditions during two years and fish sampling was made before and after cold season. Tab. 1: Length of stocking time of fish into the winter ponds ______________________Experiment________________________________Duration (days)_________________ ________The experiment no 1 (Brates station)________ 120 ________The experiment no 2 (Brates station)________ 108 _______The experiment no 3 (Vladesti station)_______ 151 The number of the days with negative temperature is shown in figure 1. Fig. 1: The days number with negative temperature during on experimental period nov dec jan febr mars @ the experiment nol month В the experiment no 2 and 3 Fish sampling stations. The fish samples were collected from the ponds of two fish farms from Galati County. The farms have similar climatic conditions and partially the same water sources. • Brates experimental fish nursery from Institute of research and development for aquatic Ecology, Fishing and Aquaculture, Galati. • Vladesti fish farm. The water source is supplied form Danube River and Brates Lake in case of Brates nursery and also from Prut River in case of both fish farms. The experiments were proceeded on four reared juvenile cyprinids species: common carp, Cyprinus carpio carpio Linnaeus, 1758, grass carp, Ctenopharyngodon idella (Valenciennes, 1844), 84
