Parques de Portugal

<p> <em>Alosa alosa</em> (Linnaeus, 1758)</p>

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  • Allis shad

  • Alosa alosa (Linnaeus, 1758)

  • Clupeidae

  • The allis shad is an anadromous (lives on the sea and goes to rivers to lay the eggs) migrating fish with a dark blue colouration and silver flanks. It exhibits a fusiform body and a cone shaped head. It can grow to be 70 cm long and can weigh 4 kg.

  • Vale do Guadiana Nature Park

    Estuário do Tejo Nature Reserve

  • Lisboa e Vale do Tejo

    Alentejo

  • Endangered

  • The allis shad lives at sea until it reaches the adult age, when it migrates to the river where it was born, to reproduce. It lays its eggs in a place with moderate currents, dying soon after. The larvae remain in the river for five months, descending into the estuary where they remain for a few more months. After the metamorphosis they migrate to sea, where they complete their development.

  • Spring and Summer

  • In the larval zooplankton stage the Allis shad feed on flies and similars (insects with two pairs of wings) and, in the zooplankton stage eats insects and other fish. In adult during the reproductive migration, does not eat.

  • The Portuguese population of this species is estimated to be between 3 thousand and 30 thousand individuals.