Brook Lampreys in River Kenfig

April is the month to look for spawning lampreys. Greg Jones sent me this image that he took of a Brook Lamprey (Lampetra planeri) collected from a spawning redd in the River Kenfig on 18th April 2007. Greg described the mass of spawning fish as looking like a clump of water weed. At 15cm the Brook Lamprey is the smallest of the three UK species and is non-migratory, River Lamprey (L. fluviatilis) 30cm and Sea Lamprey (Petromyzon marinus) 1m+ both have marine phases of the life cycle and also occur in Welsh rivers.