Table 1

Female and male gonad developmental stages in R tawarensis and their descriptions.

Stages

Classification

Macroscopic appearance

Oocyte size (μm)

GSI range

Testes

Ovary

F

M

I

Immature

Small, flat, translucent to whitish, poorly developed, with reduced fringes.

Small, transparent to translucent and not very voluminous. Oocyte not visible with naked eye.

209.61-592.78 (447.30 ± 99.42)^a

<10.9

<2.0

II

Develop

Whitish with voluminous fringes.

Large orange-pale, oocytes may be visible through the ovary tunic.

528.37-867.10 (711.24 ± 63.21)^b

11.0-18.9

2.5-5.5

III

Mature

Very large, firm, white in colour.

Very large occupying part of the abdominal cavity. Yellow oocyte turgescency.

604.15-894.33 (780.59 ± 50.71)^c

19.0-23.9

5.6-8.0

IV

Ripe

Full developed, turgid fringes, milky-whitish in colour. Milt run out of the fish.

Occupying the entire abdominal cavity. Ovulated oocytes can be fully expelled from the oviduct with gentle pressure.

725.27-991.81 (844.09 ± 57.59)^d

>24.0

> 8.0

V

Spent

Bloody and flaccid fringes.

Flaccid, red-brown or bloody in colour. Few remaining large oocytes observed, and smaller size oocytes may be seen.

227.64-770.82 (447.38 ± 139.02)^a

2.5-10.9

1.5-3.0

*Mean oocyte size in the same column followed by a different superscript is significant different (P < 0.05).

Muchlisin et al. Reproductive Biology and Endocrinology 2010 8:49   doi:10.1186/1477-7827-8-49