shad
Alosa fallax (Lacepède, 1803)
Accepted species in Catalogue of Life’s 11 September 2026 base release. This preserves the source classification and available supporting data; it is not a completed species monograph.
Twaid shad. Image taken in the lab on board of RV Belgica at Westdiep.
Hans Hillewaert · CC BY-SA 4.0 · Image sourceProvider-generated thumbnail requested at 320 pixels; no local editing Local WebP display rendition; resized without cropping.
Open encyclopedia reference
The twait shad or twaite shad (Alosa fallax) is a species of fish in the family Alosidae. It is found in the eastern Atlantic Ocean and the Mediterranean Sea and is an anadromous fish which lives in the sea but migrates into fresh water to spawn. In appearance it resembles an Atlantic herring but has a row of six to ten distinctive spots on its silvery flanks. They become mature when three or more years old and migrate to estuaries, later swimming up rivers to spawn. Populations of this fish have declined due to overfishing, pollution and habitat destruction. Conservation of this species is covered by Appendix III of the Bern Convention and Appendix II and V of the European Community Habitats Directive.
Wikipedia contributors, Twait shad; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T02:21:41.694791+00:00. This reference remains separate from the taxonomic record.
Identity & source status
- Scientific name
- Alosa fallax (Lacepède, 1803)
- Name authority
- (Lacepède, 1803)
- Common name
- shad
- Rank
- species
- Accepted status
- accepted
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Teleostei
- Order
- Clupeiformes
- Family
- Alosidae
- Genus
- Alosa
- Extinction status
- Not supplied by this source
Source habitat flags: Marine: yes · Freshwater: yes · Terrestrial: no. These do not form a complete habitat description.
Classification family tree
Nested taxonomic groups from the source. This is not a direct-ancestor chain, a dated evolutionary tree or a phylogenetic reconstruction.
- domainEukaryota (Chatton, 1925) Whittaker & Margulis, 1978
- kingdomAnimalia
- phylumChordata
- subphylumVertebrata
- infraphylumGnathostomata
- parvphylumOsteichthyes
- gigaclassActinopterygii
- superclassActinopteri
- classTeleostei
- orderClupeiformes
- suborderClupeoidei Bleeker, 1859
- familyAlosidae Svetovidov, 1952
- genusAlosa Linck, 1790
- speciesAlosa fallax (Lacepède, 1803)
Close classified relatives
These entries share the source’s genus, Alosa. They are not necessarily the closest relatives established by molecular evidence.
| Species | Classification | Source status |
|---|---|---|
| Black Sea shadAlosa maeotica (Grimm, 1901) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| blueback herringAlosa aestivalis (Mitchill, 1814) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| Alosa agone (Scopoli, 1786) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| allis shadAlosa alosa (Linnaeus, 1758) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| Alosa braschnikowi (Borodin, 1904) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| Caspian shadAlosa caspia (Eichwald, 1838) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| skipjack herringAlosa chrysochloris (Rafinesque, 1820) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| Alosa curensis (Suvorov, 1907) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| ale-wifeAlosa pseudoharengus (Wilson, 1811) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| Alosa sphaerocephala (Berg, 1913) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| Alosa suworowi (Berg, 1913) | AlosidaeChordata | Accepted speciesExtinction status not supplied |
| Alosa vistonica Economidis & Sinis, 1986 | AlosidaeChordata | Accepted speciesExtinction status not supplied |
Names & synonyms
Names explicitly linked to this accepted taxon in the source. Synonymy can change with revision.
| Recorded name | Source status |
|---|---|
| Alosa fallax nilotica (Geoffroy Saint-Hilaire, 1809) (Geoffroy Saint-Hilaire, 1809) | synonym |
| Alosa fallax rhodanensis Roule, 1924 Roule, 1924 | synonym |
| Clupea alosa elongata De la Pylaie, 1835 De la Pylaie, 1835 | synonym |
| Clupea sardinella Vallot, 1837 Vallot, 1837 | synonym |
| Alosa ficta Duhamel du Monceau, 1772 Duhamel du Monceau, 1772 | synonym |
| Alosa minor Bonaparte, 1846 Bonaparte, 1846 | synonym |
| Clupea fallax Lacepède, 1803 Lacepède, 1803 | synonym |
| Alosa fallax fallax (Lacepède, 1803) (Lacepède, 1803) | synonym |
| Alosa finta rhodanensis Roule, 1924 Roule, 1924 | synonym |
| Clupea rufa Lacepède, 1803 Lacepède, 1803 | synonym |
| Alosa finta (Cuvier, 1829) (Cuvier, 1829) | synonym |
| Alosa squamopinnata Couch, 1865 Couch, 1865 | synonym |
| Alosa fallax balticus Kukuev & Orlov, 2018 Kukuev & Orlov, 2018 | synonym |
| Alosa finta nilotica (Geoffroy Saint-Hilaire, 1809) (Geoffroy Saint-Hilaire, 1809) | synonym |
| Clupea finta Cuvier, 1829 Cuvier, 1829 | synonym |
| Clupea nilotica Geoffroy Saint-Hilaire, 1809 Geoffroy Saint-Hilaire, 1809 | synonym |
Source literature & publication evidence
References attached to this source record, including nomenclatural citations where supplied. This is a selected bibliography; abbreviated citations remain in the source’s form.
- https://www.marinespecies.org/aphia.php?p=taxdetails&id=126415 Source fields: Taxon.tsv dwc:namePublishedIn, Taxon.tsv dcterms:references
Origins, evidence & remaining research
Name authority and publication references document nomenclature where the source supplies it. They do not establish evolutionary origins or the earliest fossil occurrence.
Specimen-level evidence, morphology, ecological research, phylogenetic studies, a comprehensive bibliography and a located literary passage have not yet been compiled for this record.
Dataset citation & attribution
This exact taxon in ChecklistBank · Catalogue of Life 2026-09-11
Catalogue of Life 2026-09-11; dataset 316321; doi:10.48580/dgz5n. https://creativecommons.org/licenses/by/4.0/ . Retrieved 5 October 2026.
Stable key: col:C5M6. Classification follows source parent identifiers. English common names may vary by region.