Rosenblum, P.M. and Pudney, J. and Callard, I.P. (1987) Gonadal morphology, enzyme histochemistry and plasma steroid levels during the annual reproductive cycle of male and female brown bullhead catfish, Ictalurus nebulosus Lesueur. Journal of Fish Biology, pp. 325-34
| Species | Development state | Trait | Primary Data | Secondary Data |
| Ameiurus nebulosus | Female | Onset of oogenesis | Between middle of September until late November GSI increased 2-fold | ['September', 'November'] |
| Ameiurus nebulosus | Female | Intensifying oogenesis activity | Early May and late June (significantly increase) | ['May', 'June'] |
| Ameiurus nebulosus | Female | Maximum GSI value | 5-9 % [Late June] | 7.0 percent |
| Ameiurus nebulosus | Female | Resting period | About 1 (August-September, then slightly increased) | 1.0 months |
| Ameiurus nebulosus | Male | Main spermatogenesis activity | Early May and late June | ['May', 'June'] |
| Ameiurus nebulosus | Male | Maximum GSI value | 0.35 (Late June) | 0.35 percent |
| Ameiurus nebulosus | Male | Resting period | 0.15 (October, November) | 3.0 months |
| Ameiurus nebulosus | Spawning conditions | Spawning season | July- August | ['July', 'August'] |
| Ameiurus nebulosus | Spawning conditions | Spawning period duration | 3-6 | 4.5 weeks |