Aquaculture America 2023

February 23 - 26, 2023

New Orleans, Louisiana USA


Luke P. Oliver*, Joseph T. Evavold, and Kenneth D. Cain


Department of Fisheries and Wildlife Sciences and the Aquaculture Research Institute,

University of Idaho, Moscow, ID, 83844, USA


Optimization of triploid induction parameters was investigated for burbot using thermal and hydrostatic shock. Additionally, the sterility of sexually mature male and female triploid burbot was assessed. Timing and duration of triploid induction shocks were measured using degree minutes (°C minutes). Hydrostatic shock experiments investigated duration of shock using 7,500 or 8,500psi at 180°C minutes post-fertilization. Thermal shocks investigated duration of shock and post-fertilization shock timing using a shock of 16°C. Assessment of triploid sterility was conducted by fertilizing triploid eggs with diploid sperm, fertilizing diploid eggs with triploid sperm, and comparing fertilization, and survival to diploid males crossed with diploid females. Furthermore, diploid and triploid sperm was assessed via flow cytometry to determine ploidy and sterility. A hydrostatic shock of 7,500psi at 180°C minutes post-fertilization for 10 or 20°C minutes can induce triploidy at or over 90%, and exhibits survival that it statistically similar, p = ≤ 0.05, to controls. A hydrostatic shock of 8,500psi for 5 or 10°C minutes at 180°C minutes post-fertilization yields triploid induction of 93 and 100%, respectively, with survival that is statistically similar to controls, p = ≤ 0.05. Thermal induction experiments indicated that shocks at 16°C, 120°C minutes post-fertilization, for durations between 350 and 450°C minutes has potential to induce triploidy at or over 90% while facilitating survival statistically similar to controls, p = ≤ 0.05. Assessment of sterility determined that milt from triploid males is aneuploid and eggs from female burbot are non-functional. No surviving larvae were produced from the crosses utilizing triploid fish. Tetraploid larvae were detected in three of the optimization experiments. Results presented here provide information on optimum conditions for induction of triploidy in burbot and indicate that tetraploid burbot can be produced via hydrostatic and thermal shocks. Furthermore, assessment of sterility of 4 year old triploid burbot confirmed they are functionally sterile and would present reduced risk of uncontrolled reproduction within or outside of an aquaculture operation.