Rapid Identification of Triploid Grass Carp with a Coulter Counter and Channelyzer

Abstract

Abstract A method of electronically estimating ploidy in fishes has been developed to maximize the number of fish that can be analyzed per hour while minimizing costs. This technique uses a Coulter Counter Model ZM and a C-1000 Channelyzer to analyze distribution of erythrocyte nuclear volumes. Diploid grass carp (Ctenopharyngodon idella) possess mean nuclear volumes of 10.06 μm3 (SD = 0.60) while mean triploid nuclear volumes were 14.82 μm3 (SD = 0.96). The technique proved effective for fish that were 27 d to 3 years old, 19-905 mm total length, and rapidly growing or nutritionally stressed. With the modifications and techniques suggested, 1,600-2,400 fish can be evaluated by a three-person team in an 8-h period. Use of this technique allowed triploid grass carp to be efficiently selected and certified prior to stocking for weed control purposes.