Sea lampreys are a conundrum. In Lake Champlain they’re hated, while in the Connecticut River they’re championed. In fact, this year, Vermont Fish & Wildlife reminds anglers and the general public to avoid disturbing sea lampreys spawning in the Connecticut River and several of its tributaries because they’re native to this drainage system and beneficial to the aquatic ecosystem – while in Lake Champlain, a separate population of supposedly non-native sea lamprey are actively controlled as a nuisance species.
So not all sea lampreys are created equal. But they are all members of the most primitive group of vertebrates that first appeared in the fossil record five hundred and fifty million years ago.
Technically they’re fish that are long and thin, like eels. But calling them fish because they’re distantly related, because they breathe underwater and have a closed circulatory system with a two-chambered heart is rather like saying reptiles are mammals.
Lampreys have no jaws, no scales, no gill covers, and no paired fins. Their bones are soft and pliable, rubbery, and their mouths are suction cups with circling rows of teeth.
They begin life as filter-feeding larvae, burrowing in freshwater mud, and cleaning rivers for up to six years before returning to the Atlantic. Adults, however, are five-feet long, blood-sucking parasites, the prince of darkness for small-scaled fish.
In the ocean, they feed far offshore on large bottom-dwelling fish like haddock, switching prey often enough not to kill their host. Like salmon, sea lampreys are anadromous. To reproduce, they enter coastal rivers, stop feeding, swim upstream, spawn in the shallows, go blind, and die - in effect becoming packages of marine nutrients brought far inland.
Eagles and osprey eat spawning lamprey. In fact, I once watched a bald eagle hopping on the shoreline of the Connecticut with a thrashing lamprey in its talons. After they die, aquatic insects like caddisfly larvae - a prime foodsource for freshwater fish – feed on the remains.
There’s a debate among fish biologists about whether sea lampreys are native to lakes Ontario and Champlain. Early writings about the lakes don’t mention them, but DNA evidence seems to suggest perhaps they’ve been here for thousands of years.
Either way, sea lampreys are fish Stephen King could be proud of.
