These are often referred to as Scampi,Dublin Bay prawns, Langoustines. They are closely related to lobsters and crawfish, but do not change color when cooked. Scampi are widely distributed from Iceland to the Mediterranean, and are popular everywhere.
Scampi (from Italian scampo) is, properly, the term for the tail meat from shellfish de-headed at sea, and is most often fried. However, the whole shellfish can be poached, and then served cold or grilled. The flesh is sweet and tender, but deteriorates quickly, so most supplies are frozen. Like scallops, scampi should be cooked briefly. In dishes using a sauce, the defrosted shellfish should be added at the last moment to prevent overcooking.
This species of shellfish is very popular, mainly because it is more easily digestible than other Crustacea, but also because of its delicate, sweetish taste. They are available in several forms: whole, fresh in the shells; fresh tails; frozen tails in iced glaze; reformed and breaded. In size, scampi range from jumbo, at about 56 to the kilogram, to selected, at double that number per kilo.