A Comparative Study on Water Column and Bottom Feeding Habit of Tank Reared Brook Trout (Salvelinus fontinalis)
Ibrahim Okumus, Nadir Basçinar
KTO, Faculty of Marine Sciences, Department of Fisheries, 61530 Trabzon, TURKEY
Çanakkale 18 Mart University, Faculty of Fisheries, 17100 Çanakkale, TURKEY
Feed consumption, growth rate and feed conversion were compared for brook trout (Salvelinus fontinalis) feeding in the water column or at the tank bottom. The trial that lasted 120 days was conducted in four 300 l fiberglass tanks with two replicates; of 25 fish (mean weight of 45.9 g) in each feeding treatment. Fish fed in the water column exhibited a mean (SD) specific growth rate (SGR) of 0.93 and reached a final mean weight of 138.9 (28.5) g whereas bottom fed fish had a mean SGR of 0.91 and 135.7 (39.2) g body weight. Overall feed conversion ratios (FCR) and condition factors (CF) were assessed as 1.73, 1.22 for the water column and 1.71, 1.25 bottom fed fish. None of these variables showed statistically significant differences between the treatments. Thus, it seems that brook trout may feed both in water column and at bottom in tank culture conditions and this habit could be utilised for reducing feed waste in intensive commercial trout culture.
Key words: Brook trout (Salvelinus fontinalis), feed consumption, food conversion, growth rate, water column or bottom feeding