Scientists try to regain control of lampreys in Great Lakes
Huron Beach, Michigan
In a simple white frame building overlooking the scenic blue waters of Lake Huron, scientists are studying ways to combat the recently growing population of the sea lamprey, an eel-like parasite that nearly destroyed several fish species during the first part of this century in the Great Lakes. Researchers with the Great Lakes Fishery Commission say the sea lamprey is making a comeback despite a successful, 30-year control program. More important, the parasitic eel is flourishing in the deep, high-water volume channels of the Great Lakes' connecting rivers, which will be very difficult and expensive to treat.
``In some areas it's approaching the precontrol era of the early 1960s in Lake Huron,'' says Randy L. Eshenroder, senior scientist for the commission. ``We know we have large populations of lamprey in the St. Marys [River], and we know that is what's causing the problem in Lake Michigan and Lake Huron.''
The sea lampreys threaten the $1 billion Great Lakes fishing industry, says Mr. Eshenroder.
Scientists in the United States and Canada first noticed an increase in the sea lamprey population a couple of years ago. The fishery commission, a joint American and Canadian agency responsible for lamprey control and fishery management on the Great Lakes, established a task force in May to study the problem and recommend a program to combat it.
The sea lamprey first entered the Great Lakes from the Atlantic Ocean in the 1830s when the Welland Ship Canal, connecting Lake Ontario with Lake Erie, was completed. When it reaches adulthood, the lamprey transforms into a parasite and attaches itself to fish with its suction cup-like mouth and sharp teeth. Lampreys suck the body fluids out of fish, killing or severely injuring them. Most of the research in controlling and treating the sea lamprey is done at the commission's Hammond Bay Biological Station, south of Huron Beach, Mich. James Seelye, station chief, says the lamprey population has been controlled for 25 years through the use of TFM, a pesticide that kills larval lamprey, but has virtually no effect on other fish or humans.
Mr. Seelye points out that the commission does not have any scientific data to describe the degree of the problem. The Sea Lamprey Control Task Force is gathering data now, and a program to control the lamprey may not be ready until next year.
``We've been in the lamprey control business since 1956, and we have a program that is successful everywhere else in the Great Lakes but in my back yard,'' says Jim Tibbles, director of the Sea Lamprey Control Center based on the St. Marys River in Sault Ste. Marie, Ont.
The major problem is the volume of water that flows through the St. Marys River. ``It's deep, it's wide and it has a 100,000-cubic feet of water flowing through it per second,'' says Mr. Tibbles.
Eshenroder, who also chairs the lamprey task force, says it would take about $5 million, roughly the entire annual budget for lamprey control, to treat the St. Marys River.