Nautilus ran an article earlier this year about lampreys, fish that look like something out of the X Files. They are probably close relatives of hagfish; like hagfish, lampreys are jawless. They attach their round mouths to other fish and feed on their bodily fluids. They do not have a reputation as civilised dinner conversationalists.
While hagfish are marine animals, lampreys are anadromous: they return to fresh water (usually rivers) to spawn, in the same way that salmon do. When they’ve spawned, they die, fertilising the rivers and surrounding land with the nutrients from their bodies (in the same way as salmon do, but on a smaller scale).
Rehabilitation of North American rivers, along with the removal of dams, opens the way for fish such as salmon and alewives to return. Lampreys have returned too. Until recently they were viewed as invasive pests:
… the conventional American wisdom on sea lampreys was conceived following the late-19th- and early-20th-century collapse of world-renowned trout populations. The lampreys were invasive, having infiltrated the region through shipping canals; Great Lakes fish could not adapt to their ravages. Historical records describe the ease with which nets could be lowered to lake bottoms, then pulled back up with a cargo of sea lamprey-holed carcasses.
More recent research suggests that lampreys are native to at least Lake Ontario and several other lakes in the region, and were only able to colonise the rest of the Great Lakes when their native fish populations were all but destroyed by removing too many fish and modifying the ecosystem through damming, logging and agriculture.
Although they aren’t pretty, lampreys may be less of an invasive parasite and more of an essential participant in a balanced ecosystem than they were once thought to be. Read the Nautilus article here.
