Abstract
Sex ratio was 1:1 in normal diploid loach Misgurnus anguillicaudatus reared at a temperature of 20°C, but significant deviation of the ratio to the male was found when reared 25 and 30°C for 214 days from day 6 after hatching. In gynogenetic diploids which were considered genetic females, no males were observed at 20°C. In contast, gynogenetic males and intersexes were observed in groups reared at high temperatures (25 and 30°C) for 220 or 240 days from day 11 after hatching. Incubation of gynogens at 28°C for one month from day 11 after hatching was sufficient to produce males in gynogenetic diploids. These results indicated that high water temperature influences the sex of genetic females in the loach and then induces sex reversal to physiological males.
