Rubin, J.F. and Glimsäter, C. and Jarvi, T. (2005) Spanwing characteristics of the anadromous brown trout in a small Swedish stream. Journal of fish biology, pp. 107-121
| Species | Development state | Trait | Primary Data | Secondary Data |
| Salmo trutta fario | Female | Age at sexual maturity | Spawning males were significantly younger 2+ and 4+ years, than females 3+ to 5+ years. The oldest female was 8+ years | 2.0 year |
| Salmo trutta fario | Female | Length at sexual maturity | The Lt of spawning females ranged from 185 to 890 mm. The distribution was unimodal for females with a mean +/- SD of 572 +/- 112 mm (n=283) | 572.0 cm |
| Salmo trutta fario | Female | Weight at sexual maturity | The Mt of spawning females ranged from 55 to 8130 g | 55.0 kg |
| Salmo trutta fario | Male | Age at sexual maturity | Spawning males were significantly younger 2+ and 4+ years. The oldest male was 6+ years | 2.0 years |
| Salmo trutta fario | Male | Length at sexual maturity | The Lt of spawning males ranged from 184 to 815 mm. The distribution was multimodal for males (n=232) with most frequent length classes 300, 400 and 550 mm | 184.0 cm |
| Salmo trutta fario | Male | Weight at sexual maturity | The Mt of spawning males ranged from 56 to 6000 g | 56.0 kg |
| Salmo trutta fario | Male | Male sexual dimorphism | Once the large males, ('hooknoses', males which showed a kype on the lower jaw and Lt > 300 mm) entered Själsöan, they generally occupied a territory where they stayed. In contrast, small males ('sneakers', males without a kype on the lower jaw, and Lt> 300 mm) did not have any specific territorty and moved frequently up and downstream | Present |
| Salmo trutta fario | Spawning conditions | Spawning migration period | Anadromous brown trout spawning in large rivers, may enter fresh water some 6 months before arriving at the spawning areas, whereas brown trout spawning in small streams often ascend in a short period of time just prior to spawning | No data |
| Salmo trutta fario | Spawning conditions | Spawning period duration | Males usually entered the stream first and stayed longer, so the sex-ratio at the beginning and at the end of the spawning season was usually slanted towards males. Most of the females entered the stream and spawned the same or the next night. In contrast males tended to stay much longer in the stream (21.3% between 2 and 3 weeks) before spawning | 21.3 weeks |
| Salmo trutta fario | Spawning conditions | Spawning substrate | Spawning gravel | Lithophils |
| Salmo trutta fario | Spawning conditions | Nycthemeral period of oviposition | Spawning took place exclusively at night in Själsöan. During the day, spawning were difficult to see as they generally hide under the streambanks | Day |
| Salmo trutta fario | Spawning conditions | Mating system | Only one spawning couple was observed at one time above the redd. It was composed of a spawning female and a "hooknose" courting her. Sometimes, smaller 'sneakers' were also observed near the spawning couple. 'Sneakers' stayed downstream from the couple and waited until the female spawned. At that moment, they rapidly swam between the spawning female and male, released their sperm and swam away. | No category |
| Salmo trutta fario | Spawning conditions | Spawning release | Each female spawned all her eggs on a single spawning area in only one redd generally over one to two nights | Total |
| Salmo trutta fario | Spawning conditions | Parity | Few anadromous brown trout spawned more than once in Själsöan (7.3% of the males and 5.7% of the females). Fourteen males and 11 females were observed spawning in Själsöan 2 years in succession, and three males and two females 3 years in succession | Iteroparous |