Portuguese lamprey rice
As food
Lampreys have long been used as food for humans. They were highly appreciated by ancient Romans. During the Middle Ages, they were widely eaten by the upper classes throughout Europe, especially during fasting periods, since their taste is much meatier than that of most other fish. King Henry I of England is said to have died from eating "a surfeit of lampreys."[36]
On 4 March 1953, Queen Elizabeth II's coronation pie was made by the Royal Air Force using lampreys.[37]
Especially in southwestern Europe (Portugal, Spain, and France), and in the northern half in Finland, larger lampreys are still a highly prized delicacy. Sea lamprey is the most sought species in Portugal and one of only two that can legally bear the commercial name "lamprey" (lampreia): the other one being Lampetra fluviatilis, the European river lamprey, both according to Portaria (Government regulation no. 587/2006, from 22 June). Overfishing has reduced their number in those parts. Lampreys are also consumed in Sweden, Finland, Russia, New Zealand, the Baltic countries, Japan, and South Korea.
The mucus and serum of several lamprey species, including the Caspian lamprey (Caspiomyzon wagneri), river lampreys (Lampetra fluviatilis and L. planeri), and sea lamprey (Petromyzon marinus), are known to be toxic, and require thorough cleaning before cooking and consumption.[38][39]
In Britain, lampreys are commonly used as bait, normally as dead bait. Northern pike, perch, and chub all can be caught on lampreys. Frozen lampreys can be bought from most bait and tackle shops.