Prawns in Britain

There are more than 40 species of prawn to be found around the coast of Britain.  The distinction between the name  shrimp and prawn is not exact and in common parlance the naming tends to be contextual rather than scientific, e.g. Children collecting prawns on the beach will often refer to them as shrimps whereas their parents will call them prawns when purchased at the shop!  From a taxonomic or scientific perspective, prawns can be referred to as "palaemonid prawns" and shrimps as "crangonid shrimps" though this is not exclusive as there are seven families of prawns and shrimps.  In general, if it swims actively it is a prawn and if it scuttles, it is a shrimp though this a very simplistic view.

Classification

Phylum Arthropoda

Class Crustacea

Order Decapoda

Supersection Natantia

Section Caridea

Families

Pasiphaeidae

Palaemonidae

Alpheidae

Hippolytidae

Processidae

Pandalidae

Crangonidae

Life Cycle

Most prawns and shrimps are dioecious⁽¹⁾ though there is evidence of males in some species changing sex  at various times.  Copulation usually occurs when the female has undergone a "copulation ready" molt.  Spawning takes place shortly afterwards.  Planktonic Zoea larvae hatch shortly afterwards undergoing a number of successive molts to develop into a post-larval stage.  These "mini adult" stages then settle out of the plankton to begin final growth to maturity.  Growth occurs through stages of molting.  Prawns and shrimps have a rigid exoskeleton that protects the soft internal structure.  The exoskeleton is periodically shed as the creature grows.

Feeding

Prawns and shrimps will eat zooplankton, small crustaceans,  certain algae and carrion.

Habitat

Prawns and shrimps can occur in any marine habitat from brackish pools to the open sea. Crangonid shrimps, can be found buried in sand around estuaries and shores. The common brown shrimp, Crangon crangon,  can be found by sifting through the top layer of sand with a flat fronted net.  

Palaemon serratus

Have a look at 

Video Clip of prawn!!