First insight on the genetic base of the heritable variation of Pacific abalone ( Haliotis discus hannai ) resistance to Polydora hoplura infestation

Polydora hoplura is an invasive species and a harmful pest in commercial shellfish aquaculture, particularly for farmed abalone species. Different lines of treatment for Polydora affecting abalone have been explored, but with limited success. Using selective breeding to increase abalone resistance to and reduce shell damage from Polydora infestation could be a promising alternative. However, in abalone there is currently no information on the genetic variability for resistance to Polydora infestation. In the present study, heritability (h2) of traits associated with Pacific abalone resistance to P. hoplura were estimated after challenging abalone juveniles with trojan abalones heavily infested, using a nested experimental design, with 1 male crossed with 2-4 females. The heritability values were low but significant for some of those traits: survival h2=0.09; Infestation Intensity at Q50 h2 = 0.16 +/- 0.11; and the proportion of the shell area occupied by blisters caused by the mud-worms h2 = 0.29 +/- 0.14. These results suggest a significant potential for improving resistance or tolerance to P. hoplura infestation through selective breeding in Pacific abalone.