John Waters / Pair of Sea lampreys (Petromyzon marinus) spawning, one attempting to move a rock, River Wye, UK, June.

John Waters / Brook lamprey (Lampetra planeri) looking for food, River Kennet, Berkshire, England, UK. January.

Michel Roggo / Brook lamprey (Lampetra planeri) showing sucker, Europe

Michel Roggo / Brook lamprey (Lampetra planeri) Europe

Remi Masson / Brook lamprey (Lampetra planeri) mating in a river. Savoie, Alps, France

Willem Kolvoort / Brook lampreys (Lampetra planeri) mating in a shallow stream, the Netherlands.

Willem Kolvoort / Brook lampreys (Lampetra planeri) mating in a shallow stream, the Netherlands.

Willem Kolvoort / Brook lampreys (Lampetra planeri) nesting in a shallow stream, Holland, the Netherlands, April.

John Waters / Tilt shot looking down on a pair of Sea lampreys (Petromyzon marinus) spawning, River Wye, UK, June.

John Waters / View looking down on a pair of Sea lampreys (Petromyzon marinus) spawning, River Wye, UK, June.

John Waters / Pair of Sea lampreys (Petromyzon marinus) spawning, River Wye, UK, June.

John Waters / Sea lamprey (Petromyzon marinus) spawning, River Wye, UK, June.