Acolas, 2006



Citation


No detailed citation.

Associated characteristics


Species Development state Trait Primary Data Secondary Data
Alosa alosa Spawning conditions Mating system In 2001 and 2002, the visual observation of the number of spawners participating in a spawning act showed that > 2 individuals were involved in 45% of the spawning acts No category
Alosa alosa Spawning conditions Nycthemeral period of oviposition During 2001 and 2002, the hourly distribution of spawning acts fluctuated during the spawning period but 50% of the spawning acts were observed in a short period of time (2:00 to 4:00 U.T +2). Otherwise, water temperature reduced the length of the nocturnal spawning activity by progressively shifting the reproduction peak towards the end of the night (between 4:00 to 5:00 U.T. +2) Night
Alosa alosa Spawning conditions Spawning temperature Over the study period, the temperatures observed during spawning period varied over the range 13.3-23°C. The minimum temperature below which reproduction activity seemed to be inhibited was between 13.9 and 14°C. 18.15 °C
Alosa alosa Spawning conditions Spawning water type Water flows observed during spawning period over the three years varied between 2.7 and 47.6 m3 s-1. In 2001 and 2002, current surface speeds ranged between 0.1 and 1.5 m s-1. Flowing or turbulent water
Alosa alosa Female Age at sexual maturity Sampled individuals in 2001 and 2002 were between 3 and 6 years for males 4.5 years
Alosa alosa Spawning conditions Spawning migration period During the three years upstream migration occurred between April 6 and August 15. The main movement took place between April 29 and June 18 in 2000 (96% of the migrants), between April 25 and June 16 in 2001 (94% of the migrants) and between April 19 and May 27 in 2002 (91% of the migrants). [...] Over the three years the temperature observed during the migration varied between 10.5°C and 23°C. The temperature threshold under which migration would be inhibited seemed to be close to 11°C and was recorded in 2001 only ['April', 'August', 'May', 'June']
Alosa alosa Spawning conditions Spawning season Reproduction took place between April 24th and July 11th ['April', 'July']
Alosa alosa Female Weight at sexual maturity In females, sizes range from 600-3100 g 1850.0 kg
Alosa alosa Female Length at sexual maturity In females, sizes range from 445-670 mm 557.5 cm
Alosa alosa Male Length at sexual maturity In males, sizes ranged from 370 to 585 mm 370.0 cm
Alosa alosa Male Weight at sexual maturity From 510 to 2000 g 510.0 kg
Alosa alosa Female Age at sexual maturity Sampled individuals in 2001 and 2002 were between 4 and 7 years for females 5.5 year
Alosa alosa Spawning conditions Parity The percentage of multispawners was very low (2.1-2.5%) No category