Twaite shad (Alosa fallax)
|Researched by||Morvan Barnes||Refereed by||Admin|
|Other common names||-||Synonyms||-|
Recorded distribution in Britain and IrelandA coastal species recorded from many areas around the British Isles. Known spawning populations exist in a few rivers flowing into the Severn estuary with other possible spawning sites in southwest England and the Solway Firth.
HabitatCoastal waters returning to freshwater to spawn usually above shallow gravel substrates near deeper pools. It is a schooling and migratory species and spends most of its life offshore.
- Dorsal profile of the twaite shad is curved and the tail fins are forked.
- Body flattened side to side with strong spines along the belly.
- Deep bodied with silvery scales.
- Back deep blue in colour with silvery white sides.
- Large thin scales and scutes found along belly.
- Dark spot behind the gill cover (sometimes absent).
- Grows up to 50 cm in length.
Additional informationThe twaite shad is distinguished from the other European shad, the allis shad (Alosa alosa), by having between 40-60 gill rakers on the first gill arch while Alosa alosa has between 80-130 (Whitehead, 1985). The twaite shad is anadromous in that it spends its life in the ocean but enters rivers in April and May to spawn before returning to the sea. Juveniles remain in the rivers for up to 24 months (Muus & Nielson, 1999).
Froese, R. & Pauly, D., 2007. Fishbase. A global information system on fishes. [On-line] http://www.fishbase.org, 2008-02-18
Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.
Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]
Muus, B.J. & Nielsen, J.G. 1999. Sea Fish. Scandinavian Fishing Year Book. Hedehusene: Denmark
Whitehead, P.J.P. 1985. Clupeoid Fishes of the World: An Annotated and Illustrated Catalogue of the Herrings, Sardines, Pilchards, Sprats, Shads, Anchovies and Wolf-herring; Part 1 - Chirocentridae, Clupeidae and Pristigasteridae. FAO, 125. Rome, Italy.
Cofnod – North Wales Environmental Information Service, 2018. Miscellaneous records held on the Cofnod database. Occurrence dataset: https://doi.org/10.15468/hcgqsi accessed via GBIF.org on 2018-09-25.
NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.
Norfolk Biodiversity Information Service, 2017. NBIS Records to December 2016. Occurrence dataset: https://doi.org/10.15468/jca5lo accessed via GBIF.org on 2018-10-01.
OBIS (Ocean Biodiversity Information System), 2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-09-22
South East Wales Biodiversity Records Centre, 2018. SEWBReC Fish (South East Wales). Occurrence dataset: https://doi.org/10.15468/htsfiy accessed via GBIF.org on 2018-10-02.
Suffolk Biodiversity Information Service., 2017. Suffolk Biodiversity Information Service (SBIS) Dataset. Occurrence dataset: https://doi.org/10.15468/ab4vwo accessed via GBIF.org on 2018-10-02.
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Last Updated: 27/03/2008