Comparison of Diploid and Triploid Atlantic Salmon (Salmo salar) Physiological Embryonic Development

Diploid and triploid Atlantic salmon show distinct physiological differences including heart, brain, and digestive system morphology, propensity for certain deformities, temperature tolerance as eggs and once hatched, and different nutritional requirements. Whilst several studies have looked in detail at the rate of embryogenesis in diploid salmon, no study has compared the rate of embryogenesis between ploidies from fertilisation to hatch. This study based its assessment on a seminal paper by Gorodilov (1996) and used the same techniques to compare the rate at which triploid and diploid embryos developed morphological characteristics. Whilst no significant difference was found, this study provides well-needed justification for the assumption that both ploidies develop at the same rate and gives scientific weight to studies which involve manipulation at these stages of development. Two factors that did differ, however, were the timing of hatch, and mortality. Triploids hatched more quickly than diploids and reached 50% hatch at a significantly earlier point. Triploids also suffered from a significantly higher rate of mortality.