| Main Ref. | Allardi, J. and P. Keith, 1991 |
| Mode | dioecism |
| Fertilization | external |
| Mating type | |
| Spawning frequency | once in a lifetime |
| Spawning aggregation | Ref. |
| Batch spawner | Ref. Teletchea, F., A. Fostier, E. Kamler, J-N. Gardeur, P-Y. Le Bail, B. Jalabert and P. Fontaine, 2009 |
| Reproductive guild |
nonguarders open water/substratum egg scatterers |
| Parental Care | none |
| Description of life cycle and mating behavior | Adults in the sea begin to move towards the coast in February and congregate near or in estuaries (Ref. 10536). They ascend rivers in April and May when water temperature is 9-12 °C, peaking at 13-16 °C. Adults may migrate up to 700 km from the sea into major rivers and occasionally into the largest tributaries of these rivers to spawn (Ref. 10536). Males migrate upriver at 3-9 years; females first reproduce 1-3 years later than males. Gametogenesis occurs during spawning migration. Males arrive first in the upper reaches and occupy appropriate spawning sites, with females arriving 1-2 weeks later (Ref. 10536). Spawning sites are usually shallow areas (<1.5 m depth) of rivers near a confluence with strong currents and clean gravel bottoms (Refs. 188, 10536, 59043). Spawning occurs at night (over several nights), in large and very noisy schools that form near the surface.when water temperature reaches at least 15 °C and is believed to be optimal between 22-24 °C. (Ref. 88171). Coupling happens side by side, thrashing caudal fins on water surface and swimming in circles while expulsing eggs and sperms in the surrounding water. Eggs are fertilized in mid-water and then sink to the gravel bottom. Eggs hatch after 4-8 days (22-24 °C) (Ref. 89630). After spawning, adults return to the sea but many die before reaching it (Ref. 188, 51442, 59043). Only 5-6 % of the adults spawn more than once in their lifetime (Ref. 89655). After 3-4 months juveniles (8-12 cm length) move towards the sea until mature (Ref. 10536). Individual fish apparently return to their natal spawning site (Ref. 59043). Also Refs. 5744, 5745. |
| Search for more references on reproduction | Scirus |