Genetic parameter estimation for resistance to red tide raphidophyte Chattonella antiqua in Japanese yellowtail Seriola quinqueradiata

Abstract

Blooms of the harmful algal plankton Chattonella spp. cause severe economic damage to aquaculture. This study aimed to investigate the potential for selective breeding of resistance trait to Chattonella red tides in Japanese yellowtail Seriola quinqueradiata. Two experimental populations were prepared using different production procedures, one was produced by full factorial mating and common rearing tanks, and another was produced by pair mating and family separated rearing tanks. Fingerlings were exposed to mass cultured Chattonella antiqua and their mortality time was recorded as the phenotype of Chattonella resistance. There were significant differences in survival rate among full-sib families (range 0–50%). Heritability estimates of mortality time were moderate and similar in both populations as 0.329 ± 0.104 and 0.314 ± 0.118 respectively. The environmental variance caused by difference in rearing tanks was relatively small compared with the genetic variance, and had minimal influence on genetic parameter estimation. In contrast, body weight was highly influenced by the environmental variance of rearing tanks, thus heritability estimates varied between populations, 0.275 ± 0.102 and 0.153 ± 0.083 respectively. The genetic correlation between mortality time and body weight was not significant. This is the first report that reveals the contribution of a genetic difference to Chattonella resistance and indicates the potential for selective breeding of Chattonella resistance in Japanese yellowtail.