Como identificar Allis Shad

Para identificar Allis Shad (Alosa alosa), observe estas características principais.

Características físicas

Formato do corpo

compressed

Coloração

Dorsal side is dark blue-green, fading to silvery flanks and a white belly. Iridescent sheen, especially when freshly caught.

Tipo de escama

cycloid

Posição da boca

terminal

Características distintivas

Large, cycloid scales that are easily shed., A single, prominent dark spot behind the upper operculum, sometimes followed by 1-2 (rarely more) smaller, less distinct spots along the flank., Deep body, laterally compressed., Absence of a lateral line.

Nadadeira dorsal

Single, relatively short dorsal fin located mid-body, with 15-19 soft rays.

Nadadeira caudal

Deeply forked caudal fin, symmetrical lobes.

Nadadeira peitoral

Small, low-set pectoral fins.

Nadadeiras características

Pelvic fins are abdominal, located beneath the dorsal fin origin. No adipose fin.

Dicas de identificação

1. 1

   Body Shape and Size

   Elongated, fusiform body, laterally compressed. Adults typically range from 40-60 cm in length, with a maximum recorded length of 70 cm and weight of 4 kg.

2. 2

   Coloration

   Silvery flanks, dark blue-green back, and white belly. Often exhibits an iridescent sheen.

3. 3

   Spots

   Presence of a single, prominent dark spot behind the operculum. This is a key differentiator from Alosa fallax (Twaite Shad), which typically has a row of 4-10 distinct spots.

4. 4

   Scales

   Large, cycloid scales that are easily detached. The ventral keel is serrated.

5. 5

   Gill Rakers

   Numerous and fine gill rakers (90-120 on the lower limb of the first gill arch), adapted for filter feeding on plankton. This is a crucial internal diagnostic feature distinguishing it from Alosa fallax (Twaite Shad) which has fewer and coarser gill rakers (40-60).

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