THE EFFECT OF BODY SIZE AND WATER TEMPERATURE ON THE RESULTS OF INTENSIVE REARING OF PIKE-PERCH, STIZOSTEDION LUCIOPERCA (L.) FRY UNDER CONTROLLED CONDITIONS
The Stanisław Sakowicz Inland Fisheries Institute in Olsztyn
ABSTRACT. Studies were carried out on the effect of initial size summer pikperch fry, Stizostedion lucioperca, (two size groups), water temperature (22 and 24°C), and food type (zooplankton or artificial feeds) upon the results of rearing in controlled conditions. Weight and total length of the fish at the beginning of the experiment amounted respectively to 0.25 ± 0.06 g and 32.9 ± 2.7 mm (group S), 0.53 ± 0.06 g 39.4 ± 1.6 mm (group L). No significant effect of the initial fish size and water temperature on fish survival and losses due to cannibalism was bserved in fish which fed on zooplankton (p > 0.05). Statistical analysis revealed significant effect of initial fish size (p = 0.0011) as well as water temperature (p = 0.0001) on the survival in the groups of fish reared on artificial food. These fish attained bigger size (body weight and length) than fish in the control group (feeding on live zooplankton)(p < 0.05). Temperature had no effect on growth rate of the fish, those reared on artificial as well as natural food.
Key words: PIKE-PERCH, REARING, BODY SIZE, TEMPERATURE, SURVIVAL, CANNIBALISM