Triploidy induction in the Caspian salmon,<i>Salmo trutta caspius</i>, by heat shock

Abstract

Induction of triploidy was attempted in the Caspian salmon, Salmo trutta caspius, using heat shocks. The optimal temperature level (26, 28 and 30°C), initiation time [5, 10, 20 and 40 min post-fertilization (PF)] and duration of thermal shock (5, 10 and 20 min) required for effective induction of triploidy were investigated. Incidence of triploid fry was determined by surface and volume measurements of erythrocytes as well as from flow-cytometric analysis of some blood samples. Survival from fertilization to swim-up, triploid rates and triploid yields were in the range of 0–70%, 0–97% and 0–57%, respectively. The highest triploid yield was obtained with a shock treatment at 26°C for 10 min duration initiated 40 min PF.