How to Identify European river shad

To identify European river shad (Alosa fallax), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Silvery flanks, darker blue-green to olive-green dorsal surface. The belly is white. Often exhibits a distinct dark spot behind the operculum, followed by a series of smaller, less distinct spots along the lateral line, typically 4-8 in number.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Compressed, fusiform body., Large, deciduous scales., A single, short dorsal fin., Deeply forked caudal fin., Presence of 4-8 distinct dark spots along the flanks, posterior to the operculum (distinguishes from Alosa alosa which typically has only one spot or none).

Dorsal fin

Single, short, located mid-body, with 16-19 soft rays.

Tail fin

Deeply forked, symmetrical, with 19-21 principal rays.

Pectoral fin

Relatively small, low-set, with 13-16 soft rays.

Distinctive fins

Pelvic fins are abdominal, located beneath the dorsal fin origin, with 9 soft rays. Anal fin is long, with 19-23 soft rays.

Identification Tips

1. 1

   Body Shape and Coloration

   Look for a silvery, compressed body with a darker back. The overall appearance is sleek and streamlined.

2. 2

   Lateral Spots

   The most reliable distinguishing feature: 4-8 distinct dark spots in a row along the flanks, posterior to the operculum. The first spot is usually the largest and most prominent.

3. 3

   Mouth and Jaw

   The mouth is terminal, and the lower jaw is slightly projecting when closed. The teeth are small and deciduous.

4. 4

   Gill Rakers

   Count the gill rakers on the lower limb of the first gill arch. Alosa fallax typically has 40-60 gill rakers, which are shorter and more widely spaced than those of Alosa alosa.

5. 5

   Size

   Adults typically range from 30-50 cm (12-20 inches) in length, with a maximum recorded length of about 60 cm (24 inches) and weight up to 1.5 kg (3.3 lbs).

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