Description: This fish superficially resembles a mackerel with a moderately deep and compressed body, usually 30-40 cm but can reach up to 60 cm. Scutes (bony plates/modified scales) visible along the belly. There is usually 4-8 dark spots behind the gill opening, although some or all of these may be absent.

Habitat: This species is coastal, and found in open water from 10 - 150 m, but returns upstream to spawn in freshwater. Juvenile fish may be found in estuaries.

Distribution: Recorded around most coasts of Britain, with some documented spawning sites. Very few records exist from the island of Ireland.

Similar Species: Could be confused with Alosa alosa but it does not have 7-8 dark blotches along its side.

Key Identification Features:

• Superficially similar to a mackerel.
• 4-8 dark spots behind gill opening.

Distribution Map from NBN: Alosa fallax at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Alosa fallax at iNaturalist World Species Observations database.

GBIF data for Alosa fallax

WoRMS: Alosa fallax at World Register of Marine Species. Accepted name: Alosa fallax (Lacepède, 1803). AphiaID: 126415.

Classification: Biota; Animalia; Chordata; Vertebrata; Gnathostomata; Osteichthyes; Actinopterygii; Actinopteri; Teleostei; Clupeiformes; Alosidae; Alosa