Robert J. Wattendorf

Triploid grass carp (Ctenopharyngodon idella, 2n = 72) were found to consume an average of 127 ± 17% of their body weight in fresh hydrilla (Hydrilla verticillata) per day. Experimental fish were 199 ± 27 g at the outset, and during the 51-day trial, the 6 fish gained an average of 3.3 ± 0.5 g/ day. Total lengths increased from 243 ± 10 mm to 301 ± 15 mm (1.1 ± 0.2 mm/day) during this time. These values are equivalent to results reported by other researchers for diploid grass carp and are 3 to 4 times greater than for triploid hybrid grass carp (C. idella X Hypophthalmichthys nobilis, 2n...

Triploid hybrid grass carp (Ctenopharyngodon idella x Hypophthalmichthys nobilis) were provided known weights of hydrilla (Hydrilla verticillata) in 300 liter aquaria, to determine consumption rates for age I hybrids from 6 size groups, 21 to 37 cm total length (TL). Mean consumption rates for these groups at 26° C ranged from 25% to 52% of their body weight/day (% BW/D) or 1.7 to 8.6 g dry weight of hydrilla/day (g DW/ D). Smaller hybrids generally ate less hydrilla than larger fish, but expressed as a percentage of their body weight, small hybrids consumed more than large hybrids. The...