Genetic variation for survival and shell length of cultured red abalone (Haliotis rufescens) in Iceland

A research program was started in 1996 to study genetic variation in surviv al and size of imported red abalone cultured in Iceland. A total of 100 fam ilies was produced from a hierarchical mating design using 29 males and 88 females. Larvae from each family were settled and grown in separate ranks u ntil tagged at the age of 10 months, at which time individuals from all fam ilies were reared in one common environment, but at two farms, until the ag e of 24 months. After tagging, the abalone were fed with the macro algae sp ecies Palmaria palmata and Laminaria digitata. The mean survival rate of th e population was estimated at 9.6% at the age of 4 months, with large varia tion among families where the highest survival was 31.5% but the lowest 0.0 2%. The average shell length at the age of 8, 10, 18, and 24 months old was 13.10, 15.88, 34.99, and 50.90 mm, respectively. Heritability for survival at 4 months of age was estimated to 0.11 (0.33 on the liability scale) and for shell length at the age of 8, 10, 18, and 24 months to 0.08, 0.06, 0.2 7, and 0.34, respectively. A low, but negative, genetic correlation between the survival rate to 4 months and shell length was observed. Genotype by e nvironment interaction was negligible after rearing individuals from the sa me families in two different farms for 14 months. Based on the heritability estimates observed, it was concluded, that, theoretically, it is possible to double the growth rate of cultured red abalone in just four generations by selection at the end of 2 years of rearing.