An Evaluation of Two Egg Collection and Two Fertilization Techniques during Landlocked Fall Chinook Salmon Spawning

Abstract

AbstractIn an attempt to improve embryo survival of landlocked fall Chinook salmon Oncorhynchus tshawytscha, we compared two egg collection techniques and two different egg fertilization (sperm activation) protocols on egg survival to the eyed stage of development. A total of four treatments were used with 13 females: egg collection into a suspended net and fertilization either with or without ovarian fluid and egg collection into a hard plastic pan and subsequent fertilization either with or without ovarian fluid. There was no significant difference in survival to the eyed stage with respect to collection technique. However, the presence of ovarian fluid during sperm activation and fertilization had a small but significantly negative effect on egg survival, decreasing mean eyed egg survival by approximately 4.0%. Overall, eyed egg survival was improved in 10 of the 13 spawns fertilized without ovarian fluid. To maximize embryo survival, removal of ovarian fluid prior to fertilization is recommended for landlocked fall Chinook salmon eggs.