Noaksson, E. and Gustavsson, B. and Linderoth, M. and Zebühr, Y. and Broman, D. and Balk, L. (2004) Gonad development and plasma steroid profiles by HRGC/HRMS during one reproductive cycle in reference and leachate-exposed female perch (Perca fluviatilis). Toxicology and Applied Pharmacology, pp. 247-261
| Species | Development state | Trait | Primary Data | Secondary Data |
| Perca fluviatilis | Female | Onset of oogenesis | GSI increased from the onset of oogenesis at the end of July. The onsey of oogenesis coincided with a steady decline in water temperatures from the end of July, with the oocytes continously developing throughout the winter until a rapid increase in water temperature at the beginning of May, triigerered the spanwing. | ['January', 'February', 'March', 'May', 'July'] |
| Perca fluviatilis | Female | Intensifying oogenesis activity | March-April | ['March', 'April'] |
| Perca fluviatilis | Female | Maximum GSI value | May, 18 +/- 0.6% just before spawning. | 18.0 percent |
| Perca fluviatilis | Female | Resting period | After spawning, GSI rapidly decreased to the low values observed during the summer | 4.0 months |
| Perca fluviatilis | Spawning conditions | Spawning season | Perch in both lakes spawned in the middle of May, following a rapid 2-week increase in water temeprature from 4-6°C to 10-13°C | ['May'] |
| Perca fluviatilis | Spawning conditions | Spawning temperature | Rapid 2-week increase in water temeprature from 4-6°C to 10-13°C | 5.0 °C |