Photo © Copyright 2005 Jim Jung and licensors. All rights reserved.

Least Brook Lampreys

The Least Brook Lamprey is an extremely unlikely-looking fish to encounter in the spring-fed creeks of our region. Lacking scales, jaws, calcified bones or gill covers it looks uncannily like something from the paleozooic. Of course this is because its distant ancestors arose in the paleozooic - something like half a billion years ago - and the design has been so successful that lampreys haven't changed significantly since.

Related to the much larger Sea Lamprey which invaded the Great Lakes in the mid-20th century and destroyed the trout fisheries there, our Least Brook Lampreys are nearly identical in looks. But unlike the parasitic Sea Lampreys which attach themselves to the sides of other fish and then rasp their way into their bodies and suck out their blood and other fluids, the Least Brook Lampreys never feed as adults. Instead they spend all their time building nests, finding mates and laying eggs so the next generation will be there to carry on.

Our Least Brook Lampreys begin life in the fast flowing, highly oxygenated waters of riffles where they hatch from eggs laid by their short-lived parents. The larval lampreys then make their way to calm, quiet waters with sandy bottoms where the tiny larvae then burrow into the sand with only their small, floppy-lipped mouths protruding. Here they filter feed by ingesting water and straining out tiny stream plankton for up to seven years.

Once they have enough fat and body mass to make it as adults they metamorphose into their adult form - eight inch miniatures of their parasitic sea-going relatives - and seek out the riffles of their birth. The males build nests in these riffles by grasping pebbles with their mouths and creating small bowls in the streambed. Passing females are then courted and induced to lay their eggs in these nests which the male fertilizes. This frenzied nest building and mating continues for perhaps a week, or maybe two, and then the fasting adults - who never eat - die from starvation (and probably dissipation as well.) Not the happiest ending in the world but at least the poor lamprey adults die satisfied.

Offsite Links:

• Ohio Department of Natural Resources Least Brook Lamprey page
• "Good Lampreys are Hard to Find" Minnesota article with info on Least Brook Lamprey spawning and on problems caused by the more notorious, parasitic Sea Lamprey

Suggest a link! Send suggestions to Webmaster