Alosa fallax

  • Scientific name
  • Alosa fallax (Lacépède, 1803)

  • Common name
  • Twaite shad

  • Family
  • Clupeidae

  • External links
  • Fishbase
Trait completeness 78%
Total data155
References17
Image of Alosa fallax

Author: Fabrice Téletchéa
License: All rights reserved

Traits detail



Egg (100%)


Trait id Trait Primary data Secondary Data References
4 Egg adhesiveness No Non-Adhesive Bruslé and Quignard, 2001
4 Egg adhesiveness Non-adhesive Non-Adhesive Esteves and Andrade, 2008
5 Incubation time 3-5 4.0 days Bensettiti and Gaudillat, 2002
5 Incubation time 3-5 4.0 days Taverny, 2000
5 Incubation time 4-5 4.5 days Spillmann, 1961
5 Incubation time 4-8 6.0 days Doherty, 2004
5 Incubation time 4-6 5.0 days Maitland and Hatton-Ellis, 2000
5 Incubation time 3-5 [Incubation takes 72 to 120 hours depdning on temperature] 4.0 days Aprahamian, 2001
7 Degree-days for incubation 70-78 74.0 °C * day Bruslé and Quignard, 2001
6 Temperature for incubation >17-18 17.5 °C Bensettiti and Gaudillat, 2002
6 Temperature for incubation 15-25 [16.5-18 for Mediterranean populations] 20.0 °C Taverny, 2000
6 Temperature for incubation Successfully develop between 15 and 25°C 15.0 °C Aprahamian, 2001
2 Egg size after water-hardening 2-4.6 3.3 mm Taverny, 2000
2 Egg size after water-hardening 1.8-2.4 2.1 mm Bruslé and Quignard, 2001
2 Egg size after water-hardening 1.5-3.5 2.5 mm Maitland and Hatton-Ellis, 2000
2 Egg size after water-hardening 1.7-4.5 3.1 mm Aprahamian, 2001
2 Egg size after water-hardening Relatively large (1.7-4.5 mm) with a wide perivitelline space 3.1 mm Esteves and Andrade, 2008
3 Egg Buoyancy Pelagic and could derive but then sink to the bottom Ambiguous Bruslé and Quignard, 2001
3 Egg Buoyancy Sink to the bottom Semi-Pelagic Spillmann, 1961
3 Egg Buoyancy Sink to the bottom Semi-Pelagic Doherty, 2004
3 Egg Buoyancy Sink to the bottom Semi-Pelagic Bensettiti and Gaudillat, 2002
1 Oocyte diameter 1.2-1.5 1.35 mm Spillmann, 1961
1 Oocyte diameter 0.8-1.7 [Not specified] 1.25 mm Bensettiti and Gaudillat, 2002
1 Oocyte diameter 0.72-1.7 [Diameter of egg before hydratation] 1.21 mm Taverny, 2000
1 Oocyte diameter 1.5 1.5 mm Billard, 1997
1 Oocyte diameter In ripe ovaries, ooctye diameter reaches 1.052 mm. Nevertheless, larger oocytes (1.415 mm) can be observed in partially spent and spent ovaries, which were not shed and will be resorbed 1.052 mm Pina, 2003
1 Oocyte diameter Oocyte diameter 1.325 ± 0.032 1.325 mm Lopez, 2007

Larvae (57%)


Trait id Trait Primary Data Secondary Data References
11 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 Maitland and Hatton-Ellis, 2000
10 Reaction to light Photophobic Photophobic Taverny, 2000
8 Initial larval size 4.25-6 5.125 mm Bruslé and Quignard, 2001
8 Initial larval size 5-8 6.5 mm Taverny, 2000
8 Initial larval size About 10 10.0 mm Doherty, 2004
8 Initial larval size 4.24-9.2 at hatching 6.72 mm Aprahamian, 2001
8 Initial larval size Individuals of A. f. fallax with depleted yolk-sacs but still with some evidence of a fin fold were catagorised as shad larvae (herein embryos were 4.92-10.79 mm SL while larvae were 5.65-20.40 mm SL) 7.855 mm Esteves and Andrade, 2008
9 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 Maitland and Hatton-Ellis, 2000

Female (67%)


Trait id Trait Primary Data Secondary Data References
18 Female sexual dimorphism Female are usually older and bigger than males Absent Bensettiti and Gaudillat, 2002
18 Female sexual dimorphism Females were larger and heavier than males Absent Lopez, 2007
24 Maximum GSI value 23.31 23.31 percent Maitland and Lyle, 2005
24 Maximum GSI value 18.8 ± 7.5% 18.8 percent Doherty, 2004
24 Maximum GSI value Mean of 8.30 ± 0.83 [Between May and July] 8.3 percent Lopez, 2007
19 Relative fecundity 100 100.0 thousand eggs/kg Billard, 1997
19 Relative fecundity 85-150 117.5 thousand eggs/kg Bensettiti and Gaudillat, 2002
19 Relative fecundity 100-117 108.5 thousand eggs/kg Bruslé and Quignard, 2001
19 Relative fecundity 84-147 [Extreme values] 115.5 thousand eggs/kg Cassou-Leins, 2000
19 Relative fecundity 42,540-302,358 421.0 thousand eggs/kg Aprahamian, 2001
19 Relative fecundity 42,540-302,358, also 139,479, 147,378, 103,270, 421.0 thousand eggs/kg Maitland and Hatton-Ellis, 2000
19 Relative fecundity Mean of 46.83 ± 5.25 (n=9) 46.83 thousand eggs/kg Lopez, 2007
27 Age at sexual maturity 3-4 3.5 years Billard, 1997
27 Age at sexual maturity 2-3 2.5 years Bruslé and Quignard, 2001
27 Age at sexual maturity 3-4 [mode, but between 2-6] 3.5 years Mennesson-Boisneau, 2000
27 Age at sexual maturity 3-5 [Male] 4.0 years Maitland and Lyle, 2005
27 Age at sexual maturity Mean age of 2.95 for males 2.95 years Doherty, 2004
27 Age at sexual maturity From 2 to 9 years, with males from 3-4 years 3.5 years Aprahamian, 2001
27 Age at sexual maturity The males start to mature after three years No data Maitland and Hatton-Ellis, 2000
27 Age at sexual maturity Between 3-4 and 4-5 depedning on populations [Sex not specified] 3.5 years Bensettiti and Gaudillat, 2002
27 Age at sexual maturity The average age of female at sexual maturity range between 4.86 to 5.26 years, with a mean of 4.80 ± 0.021 years [Female mature at beween 3 and 8 years old with the majority at age 4 and 5 years at the northern limit of their distribution and at age 4 years for more southernly populations, in different sutdies mean age at maturity range from : 4/55 ± 0.9 [Wye, Whales], 4.80 ± 0.02 [severn, England],, 4.38 ± 0.31 [Barrow, England], 3.94 ± 0.13 [holland], 4.27 ± 0.2 and 3.55 ± 0.2 [Loire, France], 3.93 ± 0.21 [Charente, France], 4.27 ± 0.2 and 3.74 ± 0.14 [dordogne, France], 4.35 ± 0.21 [Adour, France], 4.66 ± 0.14 [sebou, France] 4.8 years Aprahamian and Lester, 2001
21 Oocyte development Histological data showed that the ovary of twaite shad exhibited group-synchronous development Group-synchronous Lopez, 2007
21 Oocyte development The development of oocytes in twaite shad is asynchronous because these fish are capable of bringing oocytes from an immature conditions through vitellogenesis during the spawning season. Eggs are recruited from a heterogeneous population of developing oocytes and are subsequently ovulated in several batches during each spawning season. Asynchronous Pina, 2003
20 Absolute fecundity 29-300 [Extreme values] 164.5 thousand eggs Cassou-Leins, 2000
20 Absolute fecundity 25,942-675,000 808.5 thousand eggs Aprahamian, 2001
20 Absolute fecundity 25,942-675,000 808.5 thousand eggs Maitland and Hatton-Ellis, 2000
20 Absolute fecundity Mean of 54294 ± 6174 (n=9) 54294.0 thousand eggs Lopez, 2007
17 Weight at sexual maturity 970 to 1519 g [Female specified] 970.0 kg Lopez, 2007
16 Length at sexual maturity 36.4 36.4 cm Maitland and Lyle, 2005
16 Length at sexual maturity Sizes range from 47.6 to 52.9 cm [Female specified] 47.6 cm Lopez, 2007
15 Age at sexual maturity 4-7 5.5 year Billard, 1997
15 Age at sexual maturity 3-5 4.0 year Bruslé and Quignard, 2001
15 Age at sexual maturity 4-5 [mode, but between 2-8] 4.5 year Mennesson-Boisneau, 2000
15 Age at sexual maturity 4-6 [Female specified] 5.0 year Maitland and Lyle, 2005
15 Age at sexual maturity Mean age of 5.6 for female 5.6 year Doherty, 2004
15 Age at sexual maturity From 2 to 9 years with females mainly at 4-5 years 4.5 year Aprahamian, 2001
15 Age at sexual maturity The females do not start to mature until they are about five years old No data Maitland and Hatton-Ellis, 2000
15 Age at sexual maturity Between 3-4 and 4-5 depedning on populations [Sex not specified] 3.5 year Bensettiti and Gaudillat, 2002

Male (56%)


Trait id Trait Primary Data Secondary Data References
30 Male sexual dimorphism Males mature a year earlier Absent Aprahamian, 2001
33 Maximum GSI value 11.82 11.82 percent Maitland and Lyle, 2005
33 Maximum GSI value 11.4 ± 2.9 11.4 percent Doherty, 2004
28 Length at sexual maturity 34.1 34.1 cm Maitland and Lyle, 2005
28 Length at sexual maturity For female from the Severn, the critical size appears to be approximatively 330 to 340 mm 330.0 cm Aprahamian and Lester, 2001
28 Length at sexual maturity Range from 36.5 to 46 [Male specified] 36.5 cm Lopez, 2007
29 Weight at sexual maturity Range from 523 to 905 g [Male specified] 523.0 kg Lopez, 2007

Spawning conditions (100%)


Trait id Trait Primary Data Secondary Data References
47 Mating system Schools No category Billard, 1997
47 Mating system After spawning females move downstream again, whilst males remain awaiting the chance to spawn with other females No category Maitland and Lyle, 2005
46 Nycthemeral period of oviposition Night Night Billard, 1997
46 Nycthemeral period of oviposition Night : between midnight and 2 a.m. Night Bruslé and Quignard, 2001
46 Nycthemeral period of oviposition At the beginning of the night : chiefly during 2 to 3 hours Night Cassou-Leins, 2000
46 Nycthemeral period of oviposition Night : between 10 p.m. and 2 a.m. Night Spillmann, 1961
46 Nycthemeral period of oviposition Spawning usually takes place at dusk Dusk Doherty, 2004
46 Nycthemeral period of oviposition Mainly nocturnal though has been reported during daylight Ambiguous Aprahamian, 2001
46 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 Maitland and Hatton-Ellis, 2000
46 Nycthemeral period of oviposition Spawning was observed to occur between 02:00 and 4:00 h No category Lopez, 2007
50 Parental care None No category Spillmann, 1961
44 Spawning substrate Over grounds of sand or pebbles Ambiguous Billard, 1997
44 Spawning substrate Gravels and pebbles [sometimes sand] Ambiguous Bruslé and Quignard, 2001
44 Spawning substrate Pebbles and gravels: mainly 5-9 cm but vary between 0.2-18 cm Lithophils Cassou-Leins, 2000
44 Spawning substrate Mainly gravel Lithophils Doherty, 2004
44 Spawning substrate Pelagophilous Pelagophils Balon, 1975
44 Spawning substrate Above appropriate areas of clean gravel Lithophils Maitland and Hatton-Ellis, 2000
44 Spawning substrate Occurs over susbtrate ranging from mud to sandy-gravel Ambiguous Aprahamian, 2001
44 Spawning substrate Gravel susbtrate Lithophils Lopez, 2007
45 Spawning site preparation No No category Bruslé and Quignard, 2001
45 Spawning site preparation No, eggs are released directly into the water column Open water/substratum scatter Doherty, 2004
45 Spawning site preparation Open substratum spawner Open water/substratum scatter Balon, 1975
41 Spawning temperature 15-20 17.5 °C Billard, 1997
41 Spawning temperature 18-22 20.0 °C Bruslé and Quignard, 2001
41 Spawning temperature 16-18 17.0 °C Cassou-Leins, 2000
41 Spawning temperature >15 15.0 °C Bensettiti and Gaudillat, 2002
41 Spawning temperature Water ranged from 21.7°C to 24.5°C 21.7 °C Lopez, 2007
40 Spawning period duration 3-6 In Atlantic Ocean and Mediterranean Sea populations 4.5 weeks Cassou-Leins, 2000
40 Spawning period duration Males migrate to the spawning grounds first and wait there for the females which only move in when they are close to spawing No data Maitland and Lyle, 2005
42 Spawning water type Turbide water No category Bruslé and Quignard, 2001
42 Spawning water type Chiefly 50-100 m wide, with water current of 0.9-2 m/s, also in estuaries Flowing or turbulent water Cassou-Leins, 2000
42 Spawning water type With constant current Flowing or turbulent water Spillmann, 1961
42 Spawning water type Lower reaches of the large accessible rivers along the coasts No category Maitland and Lyle, 2005
42 Spawning water type Upper tidal limit of the River No category Doherty, 2004
42 Spawning water type Flowing water Flowing or turbulent water Maitland and Hatton-Ellis, 2000
42 Spawning water type Occurs in fresh water No category Aprahamian, 2001
42 Spawning water type Enter the lower and middle rivers to spawn. Ebro River characterized by laminar fast flow areas No category Lopez, 2007
42 Spawning water type In this study, eggs, embryos and larvae of Twaite shad were only found in the upstream, riverine stations located close to the upper boundary of estuarine influence and the vicinity of the suspected spawning grounds in the River Mira No category Esteves and Andrade, 2008
43 Spawning depth 1.5-3 2.25 m Bruslé and Quignard, 2001
43 Spawning depth In water less than 3 m deep [sometimes between 15-30 cm] 22.5 m Cassou-Leins, 2000
43 Spawning depth Deep water [Depth not precised] No data Spillmann, 1961
43 Spawning depth Less than 1.5 m 1.5 m Doherty, 2004
43 Spawning depth Spawniing is a noisy affair, with much splashing and chasing near the surface No data Maitland and Hatton-Ellis, 2000
43 Spawning depth 0.15 to 8 m 0.15 m Aprahamian, 2001
43 Spawning depth 3-4 m water depth 3.5 m Lopez, 2007
36 Spawning migration distance Up to 250 km from sea (Vienne) and to 500 km (Saône), but also in estuary 250.0 km Bensettiti and Gaudillat, 2002
36 Spawning migration distance Depend but could be short, i.e. 60 km 60.0 km Bruslé and Quignard, 2001
36 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 Maitland and Hatton-Ellis, 2000
37 Spawning migration period Later than allis shad, and during a shorter time No data Bensettiti and Gaudillat, 2002
37 Spawning migration period In Ireland, mature fish enter from April to June, with peak spawning activity occuring in late May ['April', 'May', 'June'] Doherty, 2004
37 Spawning migration period The spawning migration into the estuary begins between February (southern populations) and May (northern populations), extends for thee months and is temperature depend ['February', 'May'] Aprahamian, 2001
37 Spawning migration period Mature adults enter the estuaries of many European rivers from April and migrate some distance upstream, at 10-14°C, ['April'] Maitland and Hatton-Ellis, 2000
37 Spawning migration period Pre-spawning adult enter the Sever, estuary at the start of the freswater phase of their spawning migration, between mid-April and mid-June, peak migration generally occurs in May. The timing of their movement into the estuary appears related to temperature, peak immigration occuring at temperature rangin between 10.6 and 12.3°C ['April', 'May', 'June'] Aprahamian, 1998
37 Spawning migration period This species still migrates into the River Mira and the River Guadiana, Portugal to spawn. In theses rivers, spawning migration is triggered by favourable environmental conditions, such as the increase in water temperature, and starts between March and April, when adult twaite shad congregate in the sea near the mouth of the river ['April', 'March'] Pina, 2003
37 Spawning migration period The upstream migration and spawning of European Alosa spp seems to be triggered by water temperature (above 10-12°C) and predominantly influenced by estuarine tides and river flows/discharge No data Esteves and Andrade, 2008
39 Spawning season May-June ['May', 'June'] Billard, 1997
39 Spawning season May-June ['May', 'June'] Bensettiti and Gaudillat, 2002
39 Spawning season June-July ['June', 'July'] Bruslé and Quignard, 2001
39 Spawning season March to August depends on the latitude [In Europe mainly in May] ['August', 'March', 'May'] Cassou-Leins, 2000
39 Spawning season May until end of June ['May', 'June'] Spillmann, 1961
39 Spawning season The spawning season can last until June ['June'] Pina, 2003
39 Spawning season Twaite shad eggs, embryos and larvae occurred from late-March to mid-June, with particularly higher densities during a 5-week period from late-April through to the last week of May. ['April', 'March', 'May', 'June'] Esteves and Andrade, 2008
38 Homing Presence of homing, more pronounced than that of Alosa alosa Present Bruslé and Quignard, 2001
38 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 Maitland and Hatton-Ellis, 2000
48 Spawning release Free, several batches Mutliple Spillmann, 1961
48 Spawning release Several batches during a spawning season Mutliple Bruslé and Quignard, 2001
48 Spawning release Only one batch by night, 5 to 7 batches during a spawning season Mutliple Cassou-Leins, 2000
48 Spawning release Batch spawning reproductive behavior Mutliple Lopez, 2007
48 Spawning release Evidence that twaite shad are serial spawners releasing discrete batches of eggs over an extended spawning season includes macroscopic and histologic indications of recent spawning concurrent with mature vitellogenic oocytes Mutliple Pina, 2003
49 Parity Iteroparous (could reproduce up to 5 times during a lifetime) Iteroparous Bensettiti and Gaudillat, 2002
49 Parity Iteroparous, most survive after spawning [84% of male and 77-97% of female in Gironde, France], up to 3-4 tiesin a lifespan Iteroparous Bruslé and Quignard, 2001
49 Parity Spawners get back to sea immediatly after the spawning season No category Billard, 1997
49 Parity Many twaite shad recover to spawn again next year No category Maitland and Lyle, 2005
49 Parity All populations are iteroparous, having a high proportion of repeat spawners No category Aprahamian, 2001
49 Parity May spawn several times in their lives No category Maitland and Hatton-Ellis, 2000