PREDICTION OF CLIMBING PERCH Anabas testudineus SEX DIFFERENTIATION

Sexual dimorphism of Climbing perch (Anabas testudineus) in growth rate; female grows faster than male, demand to develope a monosex culture of this species. Monosex population can be produced by hormonal treatment, prior to the timing of sexual differentiation. Due to the lack information of climbing perch sex differentiation, this research was conducted to reveal the timing of sex differentiation as an important strategy for sex reversal.

For sex differentiation study, 10 fries at 10-29 days post-hatching (dph) were sampled and stocked in to Buffered Neutral Formalin, than stained with hematoxylin and eosin. Individualy, gonad structure and differentiation status of sample are histologically analyzed.

The result showed that differentiated gonads were observed at 18-21 days post-hatching fish, was marked by the development of genital ridges concomitantly with the increasing of PGCs and appearing of ovarian cavity (Table 1 and Figure 1). Gonads of 10-16 dph was 100% undifferentiated, and 18-20 dph was 20%-40% differentiated. Furthermore, the 21-days-old fishes gonads was 100% differentiated. The result indicated that hormone administration for sex reversal must be conducted before 18-days-old.