Maitland, P.S. and Hatton-Ellis, T.W. (2000) Ecology of the Allis and Twaite shad., pp.
| Species | Development state | Trait | Primary Data | Secondary Data |
| Alosa alosa | Egg | Egg size after water-hardening | 2.5-4.5 | 3.5 mm |
| Alosa alosa | Egg | Egg Buoyancy | Semi-buoyant [Tend to drift dowstream, most falling to the bottom and remaining there in crevices, until they hatch, some eggs drift for long distances below the spawning areas, sometimes several tens of kilometres] | Pelagic |
| Alosa alosa | Egg | Egg adhesiveness | Non-adhesive | Non-Adhesive |
| Alosa alosa | Egg | Incubation time | 4-8 | 6.0 days |
| Alosa alosa | Egg | Temperature for incubation | The eggs are sensitive to water temperatures below 16-18°C, so temperatures above 18°C in June and July should be most favourable for incubation | 17.0 °C |
| Alosa alosa | Larvae | Initial larval size | About 10 on hatching | 10.0 mm |
| Alosa alosa | Larvae | Larvae behaviour | After hatching, the young remain in the slow-flowing reaches of the lower parts of rivers, then move into the estuary and eventually into coastal waters and the open sea | Demersal |
| Alosa alosa | Female | Age at sexual maturity | 3-4 [Both sex] | 3.5 year |
| Alosa alosa | Female | Length at sexual maturity | 30-40 [Both sex] | 35.0 cm |
| Alosa alosa | Female | Female sexual dimorphism | Female grow faster than males | Absent |
| Alosa alosa | Female | Relative fecundity | From 60 to 236 [There is an indication of an increase in relative fecundity with increasing latitude, from approximatively 60,000 in Morrocco to 200,000 in the River loire] | 60.0 thousand eggs/kg |
| Alosa alosa | Male | Age at sexual maturity | 3-4 [Both sex] | 3.5 years |
| Alosa alosa | Male | Length at sexual maturity | 30-40 [Both sex] | 35.0 cm |
| Alosa alosa | Spawning conditions | Spawning migration distance | In some of the larger European rivers, allis shad habe been known to ascend upstream for several hundred kilometres-for exemple, more than 500 km in the river Loire | 500.0 km |
| Alosa alosa | Spawning conditions | Spawning migration period | Move into estuaries of large rivers, migrating into fresh water during late spring (April to June) Males migrate upstream first, followed by females on or two weeks later] | ['April', 'May', 'June'] |
| Alosa alosa | Spawning conditions | Spawning migration period | Mature adults enter the estuaries of many European rivers from April and migrate some distance upstream, at about 11°C | ['April'] |
| Alosa alosa | Spawning conditions | Homing | Although there is some evidence of homing in shads, it it not known if adults return to their natal rivers or the same gravels over which they have previously spawned | Present |
| Alosa alosa | Spawning conditions | Spawning season | Throughout the range of the allis shad, reproduction occurs from April to July, but in Britain, May to July seems to have been the main period | ['April', 'May', 'June', 'July'] |
| Alosa alosa | Spawning conditions | Spawning temperature | Mostly around 15°C | 15.0 °C |
| Alosa alosa | Spawning conditions | Spawning water type | In flowing water | Flowing or turbulent water |
| Alosa alosa | Spawning conditions | Spawning water type | Current ranges from 0.5-1.5 m/s, they show a preference for spawning in swift currents at the ends of pools where gravelly shallows begin [Unlike salmonids, shads do not enter narrow streams even when these are accessible] | Flowing or turbulent water |
| Alosa alosa | Spawning conditions | Spawning depth | In water depths of 0.5-1.5 m [Spawning involves much noisy splashing at the surface] | 1.0 m |
| Alosa alosa | Spawning conditions | Spawning substrate | They deposit their eggs over a substrate that can vary from sand (0.02-2 mm) to pebbles (2-20 cm) | Lithophils |
| Alosa alosa | Spawning conditions | Nycthemeral period of oviposition | Takes place at night | Night |
| Alosa alosa | Spawning conditions | Parity | Almost all allis shad die after spawning | Semelparous |
| Alosa fallax | Egg | Egg size after water-hardening | 1.5-3.5 | 2.5 mm |
| Alosa fallax | Egg | Incubation time | 4-6 | 5.0 days |
| Alosa fallax | Larvae | Larvae behaviour | The young fish then drop quickly dowstream in the current to the quieter waters of the upper estuary where they start to feed and grow [Both eggs and larvae are transparent] | Demersal |
| Alosa fallax | Larvae | Temperature during larval development | Preference for a temperatures in the range 17-21°C for larvae 7.7-15.2 mm, and from 17-21.5°C for larvae 18.4-23.8 in length | 19.0 °C |
| Alosa fallax | Female | Age at sexual maturity | The females do not start to mature until they are about five years old | 5.0 year |
| Alosa fallax | Female | Relative fecundity | 42,540-302,358; also 139,479; 147,378; 103,270; | 421.0 thousand eggs/kg |
| Alosa fallax | Female | Absolute fecundity | 25,942-675,000 | 808.5 thousand eggs |
| Alosa fallax | Male | Age at sexual maturity | The males start to mature after three years | 3.0 years |
| Alosa fallax | Spawning conditions | Spawning migration distance | May spawn in, or just above, the tidal reaches of rivers, but many stocks spawn in freshwater upstrezam of this. Some fish travel over 190 km to reach their spawning grounds | 190.0 km |
| Alosa fallax | Spawning conditions | Spawning migration period | Mature adults enter the estuaries of many European rivers from April and migrate some distance upstream, at 10-14°C, | ['April'] |
| Alosa fallax | Spawning conditions | Homing | Although there is some evidence of homing in shads, it it not known if adults return to their natal rivers or the same gravels over which they have previously spawned | Present |
| Alosa fallax | Spawning conditions | Spawning water type | Flowing water | Flowing or turbulent water |
| Alosa fallax | Spawning conditions | Spawning water type | Unlike salmonids, shads do not enter narrow streams even when these are accessible | No category |
| Alosa fallax | Spawning conditions | Spawning water type | Riffle areas, current generally described as "fast-flowing" | Flowing or turbulent water |
| Alosa fallax | Spawning conditions | Spawning depth | Spawniing is a noisy affair, with much splashing and chasing near the surface | No data |
| Alosa fallax | Spawning conditions | Spawning depth | Shallow, areas of 30 cm or so in depth | 30.0 m |
| Alosa fallax | Spawning conditions | Spawning substrate | Above appropriate areas of clean gravel | Lithophils |
| Alosa fallax | Spawning conditions | Spawning substrate | Sandy-gravel | Lithophils |
| Alosa fallax | Spawning conditions | Nycthemeral period of oviposition | Twaite shad accumulate in pools during the, moving out onto the shallow, sandy-gravel riffle areas of 30 cm or so in depth to spawn during the night. | Night |
| Alosa fallax | Spawning conditions | Parity | May spawn several times in their lives | No category |