Comparison of Diploid and Triploid Largemouth Bass Growth and Maturation through Age 1 in Puerto Rico

Abstract

Triploid largemouth bass Micropterus salmoides could be valuable both in sport fish management and in food fish production. This study compared the growth and reproductive development of diploid and triploid largemouth bass through age 1 in Lucchetti Reservoir, Puerto Rico. We produced and stocked 487 diploids and 477 triploids tagged with binary coded wire tags and recaptured these fish over 2 years. Growth rates, condition (relative weight (W_r)), and reproductive investment (gonadosomatic index (GSI)) were compared for diploid and triploid fish. Rates of mean daily growth did not differ between diploids (0.81 mm/d; SE = 0.07) and triploids (0.91 mm/d; SE = 0.09) as juveniles or overall through age 1. Diploid largemouth bass exhibited advanced reproductive development during age 1, while triploids did not. Mean GSI was higher for diploid females (mean = 1.98; SE = 0.81) than for triploid females (mean = 0.29; SE = 0.05), but male mean GSI did not significantly differ between the two groups. No difference in W_r was observed. Experimental fish in this study reached maturity in the middle of the spawning season at age 1 and therefore may not have reproduced. Additional research on triploid largemouth bass beyond age 1 is necessary to determine whether sterile triploids have growth advantages over reproductive adult diploids.