Power to detect heritability of a continuous character in two Burrishoole Atlantic salmon cohorts. Y axis shows proportions of significant heritability estimates at a given expected heritability value. Horizontal dashed line indicates 80% power for detecting heritability. Shades of blue, green and black are data for the parent-offspring cohort pairs for 1977–1981 and 1979–1983 years, and both dataset combined, respectively. Darker and lighter shades indicate pedigrees resolved at 29 and 14 loci, respectively. The inlet shows per cent power gain in power when pedigrees were resolved at 29 loci.