Open Access
Table 1
Macroscopic gonadal maturity scale used in this study (Maier, 1908), with stage codes and corresponding descriptions.
| Stage | Description |
|---|---|
| I-Virgin | Sexual organs very small, situated close to vertebral column. Testis and ovary transparent, colourless or grey. Eggs not visible to naked eye. |
| II- Maturing virgin | Testis and ovary translucent, gray-red. Length of gonads 1/2, or slightly more, of length of ventral cavity. Individual eggs can be seen with magnifying glass. |
| III- Developing | Testis and ovary opaque, reddish with blood capillaries. Occupy about 1/2 of ventral cavity. Eggs visible to naked eye as whitish granular material. |
| IV- Developed | Testis reddish-white, no milt produced under pressure. Ovary orange-red. Eggs clearly discernible, opaque. Testis and ovary occupy about 2/3rds of ventral cavity. |
| V- Gravid | Sexual organs fill ventral cavity. Testis white. Drops of milt produced under pressure. Eggs completely round, some already translucent and ripe. |
| VI- Spawning | Roe and milt run under slight pressure. Most eggs translucent with few opaque eggs left in ovary. |
| VII- Spent | Not completely empty, no opaque eggs left in ovary. |
| VIII- Resting | Testis and ovary red and empty. A few eggs in state of resorption. |
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