Temperature-dependent index of mitotic interval t 0 in greenling Hexagrammos otakii

The aim of this study was to establish effective procedures for chromosome manipu- lation in greenling Hexagrammos otakii Jordan et Starks, which has enormous aquacultural potential. To accomplish this, temperature-dependent measurements of the mitotic intervals (τ0) were carried out. The τ0 in this fish was determined by averaging the duration of the first and third embryonic divisions at temperatures ranging 5-25°C. At higher temperatures, eggs developed faster and under- went more identical development. For greenling, τ0 were 341.1 ± 3.60 min at 5°C, 275.5 ± 4.53 min at 10°C, 189.7 ± 6.93 min at 15°C, 99.2 ± 8.27 min at 20°C and 34.2 ± 8.74 min at 25°C. There were strong, negative correlations between the τ0 and water temperatures at all temperatures studied (Y = −79.3X + 425.3, R 2 = 0.9968, where Y is the mitotic interval and X is the temperature).