Genetic Evaluation Of Survival Traits Of Pacific Abalone, Haliotis Discus Hannai Ino

Mass mortalities of Pacific abalone Haliotis discus hannai Ino juveniles after weaning hinder the development of abalone farming in China. Meanwhile, over-wintering problem also limits the Pacific abalone farming in northern China. The present study firstly compared two abalone tagging methods, and then evaluated the genetic variation of survival traits of juvenile after weaning and 1-year-old juvenile over-wintering in Pacific abalone.The main methods, results and conclusions are as follows,1.Two tagging methods including clipping and numbered plastic gluing were tested in Pacific abalone with varying sizes. The results showed that the clipping methods were superior in larger sized abalones(SL > 4cm) with tags falling off, while the numbered plastic gluing method delivered less damage to abalones. The two methods have no difference in terms of tagged abalone growth performance.2. For the first time, we reported the survival performance of juvenile Pacific abalone after weaning by using survival analysis. The result showed that the major mortality occurred in the first 20-40 days after weaning. And Cox proportional hazards model showed that crossbreds between varying parental stocks have superior survival performance than that within the same parental stock. By linear model and logit threshold model, the heretability of survival traits of juvenile Pacific abalone after weaning is of low to moderate levels.3. The present study evaluated the genetic variation of survival trait of 1-year-old juvenile Pacific abalone after over-wintering through field challenge. The heretability of survival trait of 1-year-old juvenile Pacific abalone after over-wintering is of low level, 0.11±0.10. The study might provide essentials to the genetic improvement of Pacific abalone farming in northern China.