Scientists Find Sea Lampreys Repelled by Scent of Death

The lamprey is considered a pest in the Great Lakes, where it has been working to decimate fish populations for more than 100 years

Nasty creature, the sea lamprey. With rows of gnashing, gnarled teeth hidden inside of a funnel-like sucking mouth at one end of their long, slimy bodies, lampreys look like eels ... and nobody likes those, either. The sea lamphrey spends its first three to seven years, blind and toothless, living at the bottom of rivers, hidden in the mud. Once they reach a certain size, sometimes reaching three feet long, they emerge from the mud and make their way to the sea, where they clamp onto fish with their teeth. A sharp, jabbing tongue attacks the flesh while a thick secretion from the mouth keeps the blood from clotting. If the lamphrey's prey doesn't bleed to death, it will almost certainly die from an infection.

The sea lamprey has long been considered a pest in the Great Lakes region, where it has been working to decimate fish populations for more than 100 years. It's unclear when the lamprey was first introduced to the area, but some suspect it was with the digging of the Welland Canal in the late 19th century or with improvements to the 27-mile-long Canal that were made in 1919. The Canal allowed large cargo ships -- and also lampreys -- to bypass Niagara Falls.

After making its way from Lake Ontario to Lake Erie, the sea lamprey continued to spread, soon moving into Lake Michigan, Lake Huron and Lake Superior, where it has fed on lake whitefish, lake trout, chub, lake herring and other key predator species and game fish. Because the lake trout, considered an apex predator like the lion in southern Africa or the Gray Wolf in North America, plays a vital role in the health of the Lake Superior ecosystem, researchers have been working to eliminate the invasive sea lampreys.

While tossing samples of sea lampreys used for study back into the water, a few of which had died in the bucket, a scientist at Michigan State University observed that those left living quickly moved away from the dead when given the opportunity. Armed with the knowledge that sea lampreys are terrified of the smell of their own dead, "researchers are now working to identify the specific chemical that acts as the repellant," according to a report in USA Today. If they find it, the lampreys could be forced out of the Great Lakes region once and for all -- but it isn't pretty work. As Mike Siefkes, the sea lamprey program specialist with Ann Arbor's Great Lakes Fishery Commission, told USA Today of the difficulties working closely with the decaying creatures: "[H]opefully it's the smell of success."

Image: Wikimedia Commons.