Maternal Effects in the Survival and Triploidization of Hatchery Chinook Salmon

Stocking water bodies with sterile, triploid salmonids is effective at minimizing the genetic risks caused by hatchery-wild interactions.  Although the triploid induction process has been thoroughly researched, the role of maternal effects and the impact of pressure shock duration on the survival of triploid fish have not been established.  The objective of this study was to determine the role of maternal effects and pressure shock duration on the egg and fry survival of Chinook Salmon (Oncorhynchus tshawytscha).  Eggs were sampled from eight randomly selected females and fertilized with milt from eight randomly selected males.  Eggs were pressure shocked 400 centigrade temperature minutes after fertilization at 10,000 PSI for treatments of three, four, or five minutes.  Preliminary results suggest that there is more variation in survival between female groups than variation in survival between treatment groups.  Blood samples for ploidy determination were taken at the emergent fry stage, stained using 1.5 mL of DAPI solution and stored at -20°C for future analysis.  Efforts to establish ploidy using flow cytometry are ongoing.  Preliminary results indicate that changes to the traditional ploidy determination protocols are necessary to account for the effects of freezing.